The syzbot-reported stack trace from hell in this discussion thread
actually has three nested page faults:
https://lore.kernel.org/r/000000000000d5f4fc0616e816d4@google.com
... and I think that's actually the important thing here:
- the first page fault is from user space, and triggers the vsyscall
emulation.
- the second page fault is from __do_sys_gettimeofday(), and that should
just have caused the exception that then sets the return value to
-EFAULT
- the third nested page fault is due to _raw_spin_unlock_irqrestore() ->
preempt_schedule() -> trace_sched_switch(), which then causes a BPF
trace program to run, which does that bpf_probe_read_compat(), which
causes that page fault under pagefault_disable().
It's quite the nasty backtrace, and there's a lot going on.
The problem is literally the vsyscall emulation, which sets
current->thread.sig_on_uaccess_err = 1;
and that causes the fixup_exception() code to send the signal *despite* the
exception being caught.
And I think that is in fact completely bogus. It's completely bogus
exactly because it sends that signal even when it *shouldn't* be sent -
like for the BPF user mode trace gathering.
In other words, I think the whole "sig_on_uaccess_err" thing is entirely
broken, because it makes any nested page-faults do all the wrong things.
Now, arguably, I don't think anybody should enable vsyscall emulation any
more, but this test case clearly does.
I think we should just make the "send SIGSEGV" be something that the
vsyscall emulation does on its own, not this broken per-thread state for
something that isn't actually per thread.
The x86 page fault code actually tried to deal with the "incorrect nesting"
by having that:
if (in_interrupt())
return;
which ignores the sig_on_uaccess_err case when it happens in interrupts,
but as shown by this example, these nested page faults do not need to be
about interrupts at all.
IOW, I think the only right thing is to remove that horrendously broken
code.
The attached patch looks like the ObviouslyCorrect(tm) thing to do.
NOTE! This broken code goes back to this commit in 2011:
4fc3490114 ("x86-64: Set siginfo and context on vsyscall emulation faults")
... and back then the reason was to get all the siginfo details right.
Honestly, I do not for a moment believe that it's worth getting the siginfo
details right here, but part of the commit says:
This fixes issues with UML when vsyscall=emulate.
... and so my patch to remove this garbage will probably break UML in this
situation.
I do not believe that anybody should be running with vsyscall=emulate in
2024 in the first place, much less if you are doing things like UML. But
let's see if somebody screams.
Reported-and-tested-by: syzbot+83e7f982ca045ab4405c@syzkaller.appspotmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/CAHk-=wh9D6f7HUkDgZHKmDCHUQmp+Co89GP+b8+z+G56BKeyNg@mail.gmail.com
Handle cases where the RMP table placement in the BIOS is not 2M aligned
and the kexec-ed kernel could try to allocate from within that chunk
which then causes a fatal RMP fault.
The kexec failure is illustrated below:
SEV-SNP: RMP table physical range [0x0000007ffe800000 - 0x000000807f0fffff]
BIOS-provided physical RAM map:
BIOS-e820: [mem 0x0000000000000000-0x000000000008efff] usable
BIOS-e820: [mem 0x000000000008f000-0x000000000008ffff] ACPI NVS
...
BIOS-e820: [mem 0x0000004080000000-0x0000007ffe7fffff] usable
BIOS-e820: [mem 0x0000007ffe800000-0x000000807f0fffff] reserved
BIOS-e820: [mem 0x000000807f100000-0x000000807f1fefff] usable
As seen here in the e820 memory map, the end range of the RMP table is not
aligned to 2MB and not reserved but it is usable as RAM.
Subsequently, kexec -s (KEXEC_FILE_LOAD syscall) loads it's purgatory
code and boot_param, command line and other setup data into this RAM
region as seen in the kexec logs below, which leads to fatal RMP fault
during kexec boot.
Loaded purgatory at 0x807f1fa000
Loaded boot_param, command line and misc at 0x807f1f8000 bufsz=0x1350 memsz=0x2000
Loaded 64bit kernel at 0x7ffae00000 bufsz=0xd06200 memsz=0x3894000
Loaded initrd at 0x7ff6c89000 bufsz=0x4176014 memsz=0x4176014
E820 memmap:
0000000000000000-000000000008efff (1)
000000000008f000-000000000008ffff (4)
0000000000090000-000000000009ffff (1)
...
0000004080000000-0000007ffe7fffff (1)
0000007ffe800000-000000807f0fffff (2)
000000807f100000-000000807f1fefff (1)
000000807f1ff000-000000807fffffff (2)
nr_segments = 4
segment[0]: buf=0x00000000e626d1a2 bufsz=0x4000 mem=0x807f1fa000 memsz=0x5000
segment[1]: buf=0x0000000029c67bd6 bufsz=0x1350 mem=0x807f1f8000 memsz=0x2000
segment[2]: buf=0x0000000045c60183 bufsz=0xd06200 mem=0x7ffae00000 memsz=0x3894000
segment[3]: buf=0x000000006e54f08d bufsz=0x4176014 mem=0x7ff6c89000 memsz=0x4177000
kexec_file_load: type:0, start:0x807f1fa150 head:0x1184d0002 flags:0x0
Check if RMP table start and end physical range in the e820 tables are
not aligned to 2MB and in that case map this range to reserved in all
the three e820 tables.
[ bp: Massage. ]
Fixes: c3b86e61b7 ("x86/cpufeatures: Enable/unmask SEV-SNP CPU feature")
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/df6e995ff88565262c2c7c69964883ff8aa6fc30.1714090302.git.ashish.kalra@amd.com
The TDX guest platform takes one bit from the physical address to
indicate if the page is shared (accessible by VMM). This bit is not part
of the physical_mask and is not preserved during mprotect(). As a
result, the 'shared' bit is lost during mprotect() on shared mappings.
_COMMON_PAGE_CHG_MASK specifies which PTE bits need to be preserved
during modification. AMD includes 'sme_me_mask' in the define to
preserve the 'encrypt' bit.
To cover both Intel and AMD cases, include 'cc_mask' in
_COMMON_PAGE_CHG_MASK instead of 'sme_me_mask'.
Reported-and-tested-by: Chris Oo <cho@microsoft.com>
Fixes: 41394e33f3 ("x86/tdx: Extend the confidential computing API to support TDX guests")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20240424082035.4092071-1-kirill.shutemov%40linux.intel.com
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Merge tag 'sched_urgent_for_v6.9_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fix from Borislav Petkov:
- Add a missing memory barrier in the concurrency ID mm switching
* tag 'sched_urgent_for_v6.9_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched: Add missing memory barrier in switch_mm_cid
without OBJECT_FILES_NON_STANDARD. This fixes a warning
"Unpatched return thunk in use. This should not happen!" when running
KVM selftests.
* Fix a mostly benign bug in the gfn_to_pfn_cache infrastructure where KVM
would allow userspace to refresh the cache with a bogus GPA. The bug has
existed for quite some time, but was exposed by a new sanity check added in
6.9 (to ensure a cache is either GPA-based or HVA-based).
* Drop an unused param from gfn_to_pfn_cache_invalidate_start() that got left
behind during a 6.9 cleanup.
* Fix a math goof in x86's hugepage logic for KVM_SET_MEMORY_ATTRIBUTES that
results in an array overflow (detected by KASAN).
* Fix a bug where KVM incorrectly clears root_role.direct when userspace sets
guest CPUID.
* Fix a dirty logging bug in the where KVM fails to write-protect SPTEs used
by a nested guest, if KVM is using Page-Modification Logging and the nested
hypervisor is NOT using EPT.
x86 PMU:
* Drop support for virtualizing adaptive PEBS, as KVM's implementation is
architecturally broken without an obvious/easy path forward, and because
exposing adaptive PEBS can leak host LBRs to the guest, i.e. can leak
host kernel addresses to the guest.
* Set the enable bits for general purpose counters in PERF_GLOBAL_CTRL at
RESET time, as done by both Intel and AMD processors.
* Disable LBR virtualization on CPUs that don't support LBR callstacks, as
KVM unconditionally uses PERF_SAMPLE_BRANCH_CALL_STACK when creating the
perf event, and would fail on such CPUs.
Tests:
* Fix a flaw in the max_guest_memory selftest that results in it exhausting
the supply of ucall structures when run with more than 256 vCPUs.
* Mark KVM_MEM_READONLY as supported for RISC-V in set_memory_region_test.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm fixes from Paolo Bonzini:
"This is a bit on the large side, mostly due to two changes:
- Changes to disable some broken PMU virtualization (see below for
details under "x86 PMU")
- Clean up SVM's enter/exit assembly code so that it can be compiled
without OBJECT_FILES_NON_STANDARD. This fixes a warning "Unpatched
return thunk in use. This should not happen!" when running KVM
selftests.
Everything else is small bugfixes and selftest changes:
- Fix a mostly benign bug in the gfn_to_pfn_cache infrastructure
where KVM would allow userspace to refresh the cache with a bogus
GPA. The bug has existed for quite some time, but was exposed by a
new sanity check added in 6.9 (to ensure a cache is either
GPA-based or HVA-based).
- Drop an unused param from gfn_to_pfn_cache_invalidate_start() that
got left behind during a 6.9 cleanup.
- Fix a math goof in x86's hugepage logic for
KVM_SET_MEMORY_ATTRIBUTES that results in an array overflow
(detected by KASAN).
- Fix a bug where KVM incorrectly clears root_role.direct when
userspace sets guest CPUID.
- Fix a dirty logging bug in the where KVM fails to write-protect
SPTEs used by a nested guest, if KVM is using Page-Modification
Logging and the nested hypervisor is NOT using EPT.
x86 PMU:
- Drop support for virtualizing adaptive PEBS, as KVM's
implementation is architecturally broken without an obvious/easy
path forward, and because exposing adaptive PEBS can leak host LBRs
to the guest, i.e. can leak host kernel addresses to the guest.
- Set the enable bits for general purpose counters in
PERF_GLOBAL_CTRL at RESET time, as done by both Intel and AMD
processors.
- Disable LBR virtualization on CPUs that don't support LBR
callstacks, as KVM unconditionally uses
PERF_SAMPLE_BRANCH_CALL_STACK when creating the perf event, and
would fail on such CPUs.
Tests:
- Fix a flaw in the max_guest_memory selftest that results in it
exhausting the supply of ucall structures when run with more than
256 vCPUs.
- Mark KVM_MEM_READONLY as supported for RISC-V in
set_memory_region_test"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (30 commits)
KVM: Drop unused @may_block param from gfn_to_pfn_cache_invalidate_start()
KVM: selftests: Add coverage of EPT-disabled to vmx_dirty_log_test
KVM: x86/mmu: Fix and clarify comments about clearing D-bit vs. write-protecting
KVM: x86/mmu: Remove function comments above clear_dirty_{gfn_range,pt_masked}()
KVM: x86/mmu: Write-protect L2 SPTEs in TDP MMU when clearing dirty status
KVM: x86/mmu: Precisely invalidate MMU root_role during CPUID update
KVM: VMX: Disable LBR virtualization if the CPU doesn't support LBR callstacks
perf/x86/intel: Expose existence of callback support to KVM
KVM: VMX: Snapshot LBR capabilities during module initialization
KVM: x86/pmu: Do not mask LVTPC when handling a PMI on AMD platforms
KVM: x86: Snapshot if a vCPU's vendor model is AMD vs. Intel compatible
KVM: x86: Stop compiling vmenter.S with OBJECT_FILES_NON_STANDARD
KVM: SVM: Create a stack frame in __svm_sev_es_vcpu_run()
KVM: SVM: Save/restore args across SEV-ES VMRUN via host save area
KVM: SVM: Save/restore non-volatile GPRs in SEV-ES VMRUN via host save area
KVM: SVM: Clobber RAX instead of RBX when discarding spec_ctrl_intercepted
KVM: SVM: Drop 32-bit "support" from __svm_sev_es_vcpu_run()
KVM: SVM: Wrap __svm_sev_es_vcpu_run() with #ifdef CONFIG_KVM_AMD_SEV
KVM: SVM: Create a stack frame in __svm_vcpu_run() for unwinding
KVM: SVM: Remove a useless zeroing of allocated memory
...
- Fix a mostly benign bug in the gfn_to_pfn_cache infrastructure where KVM
would allow userspace to refresh the cache with a bogus GPA. The bug has
existed for quite some time, but was exposed by a new sanity check added in
6.9 (to ensure a cache is either GPA-based or HVA-based).
- Drop an unused param from gfn_to_pfn_cache_invalidate_start() that got left
behind during a 6.9 cleanup.
- Disable support for virtualizing adaptive PEBS, as KVM's implementation is
architecturally broken and can leak host LBRs to the guest.
- Fix a bug where KVM neglects to set the enable bits for general purpose
counters in PERF_GLOBAL_CTRL when initializing the virtual PMU. Both Intel
and AMD architectures require the bits to be set at RESET in order for v2
PMUs to be backwards compatible with software that was written for v1 PMUs,
i.e. for software that will never manually set the global enables.
- Disable LBR virtualization on CPUs that don't support LBR callstacks, as
KVM unconditionally uses PERF_SAMPLE_BRANCH_CALL_STACK when creating the
virtual LBR perf event, i.e. KVM will always fail to create LBR events on
such CPUs.
- Fix a math goof in x86's hugepage logic for KVM_SET_MEMORY_ATTRIBUTES that
results in an array overflow (detected by KASAN).
- Fix a flaw in the max_guest_memory selftest that results in it exhausting
the supply of ucall structures when run with more than 256 vCPUs.
- Mark KVM_MEM_READONLY as supported for RISC-V in set_memory_region_test.
- Fix a bug where KVM incorrectly thinks a TDP MMU root is an indirect shadow
root due KVM unnecessarily clobbering root_role.direct when userspace sets
guest CPUID.
- Fix a dirty logging bug in the where KVM fails to write-protect TDP MMU
SPTEs used for L2 if Page-Modification Logging is enabled for L1 and the L1
hypervisor is NOT using EPT (if nEPT is enabled, KVM doesn't use the TDP MMU
to run L2). For simplicity, KVM always disables PML when running L2, but
the TDP MMU wasn't accounting for root-specific conditions that force write-
protect based dirty logging.
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Merge tag 'kvm-x86-fixes-6.9-rcN' of https://github.com/kvm-x86/linux into HEAD
- Fix a mostly benign bug in the gfn_to_pfn_cache infrastructure where KVM
would allow userspace to refresh the cache with a bogus GPA. The bug has
existed for quite some time, but was exposed by a new sanity check added in
6.9 (to ensure a cache is either GPA-based or HVA-based).
- Drop an unused param from gfn_to_pfn_cache_invalidate_start() that got left
behind during a 6.9 cleanup.
- Disable support for virtualizing adaptive PEBS, as KVM's implementation is
architecturally broken and can leak host LBRs to the guest.
- Fix a bug where KVM neglects to set the enable bits for general purpose
counters in PERF_GLOBAL_CTRL when initializing the virtual PMU. Both Intel
and AMD architectures require the bits to be set at RESET in order for v2
PMUs to be backwards compatible with software that was written for v1 PMUs,
i.e. for software that will never manually set the global enables.
- Disable LBR virtualization on CPUs that don't support LBR callstacks, as
KVM unconditionally uses PERF_SAMPLE_BRANCH_CALL_STACK when creating the
virtual LBR perf event, i.e. KVM will always fail to create LBR events on
such CPUs.
- Fix a math goof in x86's hugepage logic for KVM_SET_MEMORY_ATTRIBUTES that
results in an array overflow (detected by KASAN).
- Fix a flaw in the max_guest_memory selftest that results in it exhausting
the supply of ucall structures when run with more than 256 vCPUs.
- Mark KVM_MEM_READONLY as supported for RISC-V in set_memory_region_test.
- Fix a bug where KVM incorrectly thinks a TDP MMU root is an indirect shadow
root due KVM unnecessarily clobbering root_role.direct when userspace sets
guest CPUID.
- Fix a dirty logging bug in the where KVM fails to write-protect TDP MMU
SPTEs used for L2 if Page-Modification Logging is enabled for L1 and the L1
hypervisor is NOT using EPT (if nEPT is enabled, KVM doesn't use the TDP MMU
to run L2). For simplicity, KVM always disables PML when running L2, but
the TDP MMU wasn't accounting for root-specific conditions that force write-
protect based dirty logging.
Many architectures' switch_mm() (e.g. arm64) do not have an smp_mb()
which the core scheduler code has depended upon since commit:
commit 223baf9d17 ("sched: Fix performance regression introduced by mm_cid")
If switch_mm() doesn't call smp_mb(), sched_mm_cid_remote_clear() can
unset the actively used cid when it fails to observe active task after it
sets lazy_put.
There *is* a memory barrier between storing to rq->curr and _return to
userspace_ (as required by membarrier), but the rseq mm_cid has stricter
requirements: the barrier needs to be issued between store to rq->curr
and switch_mm_cid(), which happens earlier than:
- spin_unlock(),
- switch_to().
So it's fine when the architecture switch_mm() happens to have that
barrier already, but less so when the architecture only provides the
full barrier in switch_to() or spin_unlock().
It is a bug in the rseq switch_mm_cid() implementation. All architectures
that don't have memory barriers in switch_mm(), but rather have the full
barrier either in finish_lock_switch() or switch_to() have them too late
for the needs of switch_mm_cid().
Introduce a new smp_mb__after_switch_mm(), defined as smp_mb() in the
generic barrier.h header, and use it in switch_mm_cid() for scheduler
transitions where switch_mm() is expected to provide a memory barrier.
Architectures can override smp_mb__after_switch_mm() if their
switch_mm() implementation provides an implicit memory barrier.
Override it with a no-op on x86 which implicitly provide this memory
barrier by writing to CR3.
Fixes: 223baf9d17 ("sched: Fix performance regression introduced by mm_cid")
Reported-by: levi.yun <yeoreum.yun@arm.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> # for arm64
Acked-by: Dave Hansen <dave.hansen@linux.intel.com> # for x86
Cc: <stable@vger.kernel.org> # 6.4.x
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20240415152114.59122-2-mathieu.desnoyers@efficios.com
Add a "has_callstack" field to the x86_pmu_lbr structure used to pass
information to KVM, and set it accordingly in x86_perf_get_lbr(). KVM
will use has_callstack to avoid trying to create perf LBR events with
PERF_SAMPLE_BRANCH_CALL_STACK on CPUs that don't support callstacks.
Reviewed-by: Mingwei Zhang <mizhang@google.com>
Link: https://lore.kernel.org/r/20240307011344.835640-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Add kvm_vcpu_arch.is_amd_compatible to cache if a vCPU's vendor model is
compatible with AMD, i.e. if the vCPU vendor is AMD or Hygon, along with
helpers to check if a vCPU is compatible AMD vs. Intel. To handle Intel
vs. AMD behavior related to masking the LVTPC entry, KVM will need to
check for vendor compatibility on every PMI injection, i.e. querying for
AMD will soon be a moderately hot path.
Note! This subtly (or maybe not-so-subtly) makes "Intel compatible" KVM's
default behavior, both if userspace omits (or never sets) CPUID 0x0 and if
userspace sets a completely unknown vendor. One could argue that KVM
should treat such vCPUs as not being compatible with Intel *or* AMD, but
that would add useless complexity to KVM.
KVM needs to do *something* in the face of vendor specific behavior, and
so unless KVM conjured up a magic third option, choosing to treat unknown
vendors as neither Intel nor AMD means that checks on AMD compatibility
would yield Intel behavior, and checks for Intel compatibility would yield
AMD behavior. And that's far worse as it would effectively yield random
behavior depending on whether KVM checked for AMD vs. Intel vs. !AMD vs.
!Intel. And practically speaking, all x86 CPUs follow either Intel or AMD
architecture, i.e. "supporting" an unknown third architecture adds no
value.
Deliberately don't convert any of the existing guest_cpuid_is_intel()
checks, as the Intel side of things is messier due to some flows explicitly
checking for exactly vendor==Intel, versus some flows assuming anything
that isn't "AMD compatible" gets Intel behavior. The Intel code will be
cleaned up in the future.
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20240405235603.1173076-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Branch History Injection (BHI) attacks may allow a malicious application to
influence indirect branch prediction in kernel by poisoning the branch
history. eIBRS isolates indirect branch targets in ring0. The BHB can
still influence the choice of indirect branch predictor entry, and although
branch predictor entries are isolated between modes when eIBRS is enabled,
the BHB itself is not isolated between modes.
Add mitigations against it either with the help of microcode or with
software sequences for the affected CPUs.
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Merge tag 'nativebhi' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 mitigations from Thomas Gleixner:
"Mitigations for the native BHI hardware vulnerabilty:
Branch History Injection (BHI) attacks may allow a malicious
application to influence indirect branch prediction in kernel by
poisoning the branch history. eIBRS isolates indirect branch targets
in ring0. The BHB can still influence the choice of indirect branch
predictor entry, and although branch predictor entries are isolated
between modes when eIBRS is enabled, the BHB itself is not isolated
between modes.
Add mitigations against it either with the help of microcode or with
software sequences for the affected CPUs"
[ This also ends up enabling the full mitigation by default despite the
system call hardening, because apparently there are other indirect
calls that are still sufficiently reachable, and the 'auto' case just
isn't hardened enough.
We'll have some more inevitable tweaking in the future - Linus ]
* tag 'nativebhi' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
KVM: x86: Add BHI_NO
x86/bhi: Mitigate KVM by default
x86/bhi: Add BHI mitigation knob
x86/bhi: Enumerate Branch History Injection (BHI) bug
x86/bhi: Define SPEC_CTRL_BHI_DIS_S
x86/bhi: Add support for clearing branch history at syscall entry
x86/syscall: Don't force use of indirect calls for system calls
x86/bugs: Change commas to semicolons in 'spectre_v2' sysfs file
BHI mitigation mode spectre_bhi=auto does not deploy the software
mitigation by default. In a cloud environment, it is a likely scenario
where userspace is trusted but the guests are not trusted. Deploying
system wide mitigation in such cases is not desirable.
Update the auto mode to unconditionally mitigate against malicious
guests. Deploy the software sequence at VMexit in auto mode also, when
hardware mitigation is not available. Unlike the force =on mode,
software sequence is not deployed at syscalls in auto mode.
Suggested-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Branch history clearing software sequences and hardware control
BHI_DIS_S were defined to mitigate Branch History Injection (BHI).
Add cmdline spectre_bhi={on|off|auto} to control BHI mitigation:
auto - Deploy the hardware mitigation BHI_DIS_S, if available.
on - Deploy the hardware mitigation BHI_DIS_S, if available,
otherwise deploy the software sequence at syscall entry and
VMexit.
off - Turn off BHI mitigation.
The default is auto mode which does not deploy the software sequence
mitigation. This is because of the hardening done in the syscall
dispatch path, which is the likely target of BHI.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Mitigation for BHI is selected based on the bug enumeration. Add bits
needed to enumerate BHI bug.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Newer processors supports a hardware control BHI_DIS_S to mitigate
Branch History Injection (BHI). Setting BHI_DIS_S protects the kernel
from userspace BHI attacks without having to manually overwrite the
branch history.
Define MSR_SPEC_CTRL bit BHI_DIS_S and its enumeration CPUID.BHI_CTRL.
Mitigation is enabled later.
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Branch History Injection (BHI) attacks may allow a malicious application to
influence indirect branch prediction in kernel by poisoning the branch
history. eIBRS isolates indirect branch targets in ring0. The BHB can
still influence the choice of indirect branch predictor entry, and although
branch predictor entries are isolated between modes when eIBRS is enabled,
the BHB itself is not isolated between modes.
Alder Lake and new processors supports a hardware control BHI_DIS_S to
mitigate BHI. For older processors Intel has released a software sequence
to clear the branch history on parts that don't support BHI_DIS_S. Add
support to execute the software sequence at syscall entry and VMexit to
overwrite the branch history.
For now, branch history is not cleared at interrupt entry, as malicious
applications are not believed to have sufficient control over the
registers, since previous register state is cleared at interrupt
entry. Researchers continue to poke at this area and it may become
necessary to clear at interrupt entry as well in the future.
This mitigation is only defined here. It is enabled later.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Co-developed-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Make <asm/syscall.h> build a switch statement instead, and the compiler can
either decide to generate an indirect jump, or - more likely these days due
to mitigations - just a series of conditional branches.
Yes, the conditional branches also have branch prediction, but the branch
prediction is much more controlled, in that it just causes speculatively
running the wrong system call (harmless), rather than speculatively running
possibly wrong random less controlled code gadgets.
This doesn't mitigate other indirect calls, but the system call indirection
is the first and most easily triggered case.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
When done from a virtual machine, instructions that touch APIC memory
must be emulated. By convention, MMIO accesses are typically performed
via io.h helpers such as readl() or writeq() to simplify instruction
emulation/decoding (ex: in KVM hosts and SEV guests) [0].
Currently, native_apic_mem_read() does not follow this convention,
allowing the compiler to emit instructions other than the MOV
instruction generated by readl(). In particular, when the kernel is
compiled with clang and run as a SEV-ES or SEV-SNP guest, the compiler
would emit a TESTL instruction which is not supported by the SEV-ES
emulator, causing a boot failure in that environment. It is likely the
same problem would happen in a TDX guest as that uses the same
instruction emulator as SEV-ES.
To make sure all emulators can emulate APIC memory reads via MOV, use
the readl() function in native_apic_mem_read(). It is expected that any
emulator would support MOV in any addressing mode as it is the most
generic and is what is usually emitted currently.
The TESTL instruction is emitted when native_apic_mem_read() is inlined
into apic_mem_wait_icr_idle(). The emulator comes from
insn_decode_mmio() in arch/x86/lib/insn-eval.c. It's not worth it to
extend insn_decode_mmio() to support more instructions since, in theory,
the compiler could choose to output nearly any instruction for such
reads which would bloat the emulator beyond reason.
[0] https://lore.kernel.org/all/20220405232939.73860-12-kirill.shutemov@linux.intel.com/
[ bp: Massage commit message, fix typos. ]
Signed-off-by: Adam Dunlap <acdunlap@google.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Kevin Loughlin <kevinloughlin@google.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20240318230927.2191933-1-acdunlap@google.com
We want to fix:
0e11073247 ("x86/retpoline: Do the necessary fixup to the Zen3/4 srso return thunk for !SRSO")
So merge in Linus's latest into x86/urgent to have it available.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add CPUID_LNX_5 to track cpufeatures' word 21, and add the appropriate
compile-time assert in KVM to prevent direct lookups on the features in
CPUID_LNX_5. KVM uses X86_FEATURE_* flags to manage guest CPUID, and so
must translate features that are scattered by Linux from the Linux-defined
bit to the hardware-defined bit, i.e. should never try to directly access
scattered features in guest CPUID.
Opportunistically add NR_CPUID_WORDS to enum cpuid_leafs, along with a
compile-time assert in KVM's CPUID infrastructure to ensure that future
additions update cpuid_leafs along with NCAPINTS.
No functional change intended.
Fixes: 7f274e609f ("x86/cpufeatures: Add new word for scattered features")
Cc: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fairly usual collection of driver and core fixes. The large selftest
accompanying one of the fixes is also becoming a common occurrence.
Current release - regressions:
- ipv6: fix infinite recursion in fib6_dump_done()
- net/rds: fix possible null-deref in newly added error path
Current release - new code bugs:
- net: do not consume a full cacheline for system_page_pool
- bpf: fix bpf_arena-related file descriptor leaks in the verifier
- drv: ice: fix freeing uninitialized pointers, fixing misuse of
the newfangled __free() auto-cleanup
Previous releases - regressions:
- x86/bpf: fixes the BPF JIT with retbleed=stuff
- xen-netfront: add missing skb_mark_for_recycle, fix page pool
accounting leaks, revealed by recently added explicit warning
- tcp: fix bind() regression for v6-only wildcard and v4-mapped-v6
non-wildcard addresses
- Bluetooth:
- replace "hci_qca: Set BDA quirk bit if fwnode exists in DT"
with better workarounds to un-break some buggy Qualcomm devices
- set conn encrypted before conn establishes, fix re-connecting
to some headsets which use slightly unusual sequence of msgs
- mptcp:
- prevent BPF accessing lowat from a subflow socket
- don't account accept() of non-MPC client as fallback to TCP
- drv: mana: fix Rx DMA datasize and skb_over_panic
- drv: i40e: fix VF MAC filter removal
Previous releases - always broken:
- gro: various fixes related to UDP tunnels - netns crossing problems,
incorrect checksum conversions, and incorrect packet transformations
which may lead to panics
- bpf: support deferring bpf_link dealloc to after RCU grace period
- nf_tables:
- release batch on table validation from abort path
- release mutex after nft_gc_seq_end from abort path
- flush pending destroy work before exit_net release
- drv: r8169: skip DASH fw status checks when DASH is disabled
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-6.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Jakub Kicinski:
"Including fixes from netfilter, bluetooth and bpf.
Fairly usual collection of driver and core fixes. The large selftest
accompanying one of the fixes is also becoming a common occurrence.
Current release - regressions:
- ipv6: fix infinite recursion in fib6_dump_done()
- net/rds: fix possible null-deref in newly added error path
Current release - new code bugs:
- net: do not consume a full cacheline for system_page_pool
- bpf: fix bpf_arena-related file descriptor leaks in the verifier
- drv: ice: fix freeing uninitialized pointers, fixing misuse of the
newfangled __free() auto-cleanup
Previous releases - regressions:
- x86/bpf: fixes the BPF JIT with retbleed=stuff
- xen-netfront: add missing skb_mark_for_recycle, fix page pool
accounting leaks, revealed by recently added explicit warning
- tcp: fix bind() regression for v6-only wildcard and v4-mapped-v6
non-wildcard addresses
- Bluetooth:
- replace "hci_qca: Set BDA quirk bit if fwnode exists in DT" with
better workarounds to un-break some buggy Qualcomm devices
- set conn encrypted before conn establishes, fix re-connecting to
some headsets which use slightly unusual sequence of msgs
- mptcp:
- prevent BPF accessing lowat from a subflow socket
- don't account accept() of non-MPC client as fallback to TCP
- drv: mana: fix Rx DMA datasize and skb_over_panic
- drv: i40e: fix VF MAC filter removal
Previous releases - always broken:
- gro: various fixes related to UDP tunnels - netns crossing
problems, incorrect checksum conversions, and incorrect packet
transformations which may lead to panics
- bpf: support deferring bpf_link dealloc to after RCU grace period
- nf_tables:
- release batch on table validation from abort path
- release mutex after nft_gc_seq_end from abort path
- flush pending destroy work before exit_net release
- drv: r8169: skip DASH fw status checks when DASH is disabled"
* tag 'net-6.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (81 commits)
netfilter: validate user input for expected length
net/sched: act_skbmod: prevent kernel-infoleak
net: usb: ax88179_178a: avoid the interface always configured as random address
net: dsa: sja1105: Fix parameters order in sja1110_pcs_mdio_write_c45()
net: ravb: Always update error counters
net: ravb: Always process TX descriptor ring
netfilter: nf_tables: discard table flag update with pending basechain deletion
netfilter: nf_tables: Fix potential data-race in __nft_flowtable_type_get()
netfilter: nf_tables: reject new basechain after table flag update
netfilter: nf_tables: flush pending destroy work before exit_net release
netfilter: nf_tables: release mutex after nft_gc_seq_end from abort path
netfilter: nf_tables: release batch on table validation from abort path
Revert "tg3: Remove residual error handling in tg3_suspend"
tg3: Remove residual error handling in tg3_suspend
net: mana: Fix Rx DMA datasize and skb_over_panic
net/sched: fix lockdep splat in qdisc_tree_reduce_backlog()
net: phy: micrel: lan8814: Fix when enabling/disabling 1-step timestamping
net: stmmac: fix rx queue priority assignment
net: txgbe: fix i2c dev name cannot match clkdev
net: fec: Set mac_managed_pm during probe
...
The host SNP worthiness can determined later, after alternatives have
been patched, in snp_rmptable_init() depending on cmdline options like
iommu=pt which is incompatible with SNP, for example.
Which means that one cannot use X86_FEATURE_SEV_SNP and will need to
have a special flag for that control.
Use that newly added CC_ATTR_HOST_SEV_SNP in the appropriate places.
Move kdump_sev_callback() to its rightful place, while at it.
Fixes: 216d106c7f ("x86/sev: Add SEV-SNP host initialization support")
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Tested-by: Srikanth Aithal <sraithal@amd.com>
Link: https://lore.kernel.org/r/20240327154317.29909-6-bp@alien8.de
There are few uses of CoCo that don't rely on working cryptography and
hence a working RNG. Unfortunately, the CoCo threat model means that the
VM host cannot be trusted and may actively work against guests to
extract secrets or manipulate computation. Since a malicious host can
modify or observe nearly all inputs to guests, the only remaining source
of entropy for CoCo guests is RDRAND.
If RDRAND is broken -- due to CPU hardware fault -- the RNG as a whole
is meant to gracefully continue on gathering entropy from other sources,
but since there aren't other sources on CoCo, this is catastrophic.
This is mostly a concern at boot time when initially seeding the RNG, as
after that the consequences of a broken RDRAND are much more
theoretical.
So, try at boot to seed the RNG using 256 bits of RDRAND output. If this
fails, panic(). This will also trigger if the system is booted without
RDRAND, as RDRAND is essential for a safe CoCo boot.
Add this deliberately to be "just a CoCo x86 driver feature" and not
part of the RNG itself. Many device drivers and platforms have some
desire to contribute something to the RNG, and add_device_randomness()
is specifically meant for this purpose.
Any driver can call it with seed data of any quality, or even garbage
quality, and it can only possibly make the quality of the RNG better or
have no effect, but can never make it worse.
Rather than trying to build something into the core of the RNG, consider
the particular CoCo issue just a CoCo issue, and therefore separate it
all out into driver (well, arch/platform) code.
[ bp: Massage commit message. ]
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Elena Reshetova <elena.reshetova@intel.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240326160735.73531-1-Jason@zx2c4.com
- Ensure perf events programmed to count during guest execution
are actually enabled before entering the guest in the nVHE
configuration.
- Restore out-of-range handler for stage-2 translation faults.
- Several fixes to stage-2 TLB invalidations to avoid stale
translations, possibly including partial walk caches.
- Fix early handling of architectural VHE-only systems to ensure E2H is
appropriately set.
- Correct a format specifier warning in the arch_timer selftest.
- Make the KVM banner message correctly handle all of the possible
configurations.
RISC-V:
- Remove redundant semicolon in num_isa_ext_regs().
- Fix APLIC setipnum_le/be write emulation.
- Fix APLIC in_clrip[x] read emulation.
x86:
- Fix a bug in KVM_SET_CPUID{2,} where KVM looks at the wrong CPUID entries (old
vs. new) and ultimately neglects to clear PV_UNHALT from vCPUs with HLT-exiting
disabled.
- Documentation fixes for SEV.
- Fix compat ABI for KVM_MEMORY_ENCRYPT_OP.
- Fix a 14-year-old goof in a declaration shared by host and guest; the enabled
field used by Linux when running as a guest pushes the size of "struct
kvm_vcpu_pv_apf_data" from 64 to 68 bytes. This is really unconsequential
because KVM never consumes anything beyond the first 64 bytes, but the
resulting struct does not match the documentation.
Selftests:
- Fix spelling mistake in arch_timer selftest.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM fixes from Paolo Bonzini:
"ARM:
- Ensure perf events programmed to count during guest execution are
actually enabled before entering the guest in the nVHE
configuration
- Restore out-of-range handler for stage-2 translation faults
- Several fixes to stage-2 TLB invalidations to avoid stale
translations, possibly including partial walk caches
- Fix early handling of architectural VHE-only systems to ensure E2H
is appropriately set
- Correct a format specifier warning in the arch_timer selftest
- Make the KVM banner message correctly handle all of the possible
configurations
RISC-V:
- Remove redundant semicolon in num_isa_ext_regs()
- Fix APLIC setipnum_le/be write emulation
- Fix APLIC in_clrip[x] read emulation
x86:
- Fix a bug in KVM_SET_CPUID{2,} where KVM looks at the wrong CPUID
entries (old vs. new) and ultimately neglects to clear PV_UNHALT
from vCPUs with HLT-exiting disabled
- Documentation fixes for SEV
- Fix compat ABI for KVM_MEMORY_ENCRYPT_OP
- Fix a 14-year-old goof in a declaration shared by host and guest;
the enabled field used by Linux when running as a guest pushes the
size of "struct kvm_vcpu_pv_apf_data" from 64 to 68 bytes. This is
really unconsequential because KVM never consumes anything beyond
the first 64 bytes, but the resulting struct does not match the
documentation
Selftests:
- Fix spelling mistake in arch_timer selftest"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (25 commits)
KVM: arm64: Rationalise KVM banner output
arm64: Fix early handling of FEAT_E2H0 not being implemented
KVM: arm64: Ensure target address is granule-aligned for range TLBI
KVM: arm64: Use TLBI_TTL_UNKNOWN in __kvm_tlb_flush_vmid_range()
KVM: arm64: Don't pass a TLBI level hint when zapping table entries
KVM: arm64: Don't defer TLB invalidation when zapping table entries
KVM: selftests: Fix __GUEST_ASSERT() format warnings in ARM's arch timer test
KVM: arm64: Fix out-of-IPA space translation fault handling
KVM: arm64: Fix host-programmed guest events in nVHE
RISC-V: KVM: Fix APLIC in_clrip[x] read emulation
RISC-V: KVM: Fix APLIC setipnum_le/be write emulation
RISC-V: KVM: Remove second semicolon
KVM: selftests: Fix spelling mistake "trigged" -> "triggered"
Documentation: kvm/sev: clarify usage of KVM_MEMORY_ENCRYPT_OP
Documentation: kvm/sev: separate description of firmware
KVM: SEV: fix compat ABI for KVM_MEMORY_ENCRYPT_OP
KVM: selftests: Check that PV_UNHALT is cleared when HLT exiting is disabled
KVM: x86: Use actual kvm_cpuid.base for clearing KVM_FEATURE_PV_UNHALT
KVM: x86: Introduce __kvm_get_hypervisor_cpuid() helper
KVM: SVM: Return -EINVAL instead of -EBUSY on attempt to re-init SEV/SEV-ES
...
- Ensure perf events programmed to count during guest execution
are actually enabled before entering the guest in the nVHE
configuration.
- Restore out-of-range handler for stage-2 translation faults.
- Several fixes to stage-2 TLB invalidations to avoid stale
translations, possibly including partial walk caches.
- Fix early handling of architectural VHE-only systems to ensure E2H is
appropriately set.
- Correct a format specifier warning in the arch_timer selftest.
- Make the KVM banner message correctly handle all of the possible
configurations.
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Merge tag 'kvmarm-fixes-6.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm64 fixes for 6.9, part #1
- Ensure perf events programmed to count during guest execution
are actually enabled before entering the guest in the nVHE
configuration.
- Restore out-of-range handler for stage-2 translation faults.
- Several fixes to stage-2 TLB invalidations to avoid stale
translations, possibly including partial walk caches.
- Fix early handling of architectural VHE-only systems to ensure E2H is
appropriately set.
- Correct a format specifier warning in the arch_timer selftest.
- Make the KVM banner message correctly handle all of the possible
configurations.
The commit:
59bec00ace ("x86/percpu: Introduce %rip-relative addressing to PER_CPU_VAR()")
made PER_CPU_VAR() to use rip-relative addressing, hence
INCREMENT_CALL_DEPTH macro and skl_call_thunk_template got rip-relative
asm code inside of it. A follow up commit:
17bce3b2ae ("x86/callthunks: Handle %rip-relative relocations in call thunk template")
changed x86_call_depth_emit_accounting() to use apply_relocation(),
but mistakenly assumed that the code is being patched in-place (where
the destination of the relocation matches the address of the code),
using *pprog as the destination ip. This is not true for the call depth
accounting, emitted by the BPF JIT, so the calculated address was wrong,
JIT-ed BPF progs on kernels with call depth tracking got broken and
usually caused a page fault.
Pass the destination IP when the BPF JIT emits call depth accounting.
Fixes: 17bce3b2ae ("x86/callthunks: Handle %rip-relative relocations in call thunk template")
Signed-off-by: Joan Bruguera Micó <joanbrugueram@gmail.com>
Reviewed-by: Uros Bizjak <ubizjak@gmail.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20240401185821.224068-3-ubizjak@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
- Use the correct stalled cycles PMCs on AMD Zen2 and newer
- Fix detection of the LBR freeze feature on AMD
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Merge tag 'perf_urgent_for_v6.9_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 perf fixes from Borislav Petkov:
- Define the correct set of default hw events on AMD Zen4
- Use the correct stalled cycles PMCs on AMD Zen2 and newer
- Fix detection of the LBR freeze feature on AMD
* tag 'perf_urgent_for_v6.9_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/amd/core: Define a proper ref-cycles event for Zen 4 and later
perf/x86/amd/core: Update and fix stalled-cycles-* events for Zen 2 and later
perf/x86/amd/lbr: Use freeze based on availability
x86/cpufeatures: Add new word for scattered features
make ... arch/x86/virt/vmx/tdx/seamcall.o
work again
- Do not do ROM range scans and memory validation when the kernel is
running as a SEV-SNP guest as those can get problematic and, before
that, are not really needed in such a guest
- Exclude the build-time generated vdso-image-x32.o object from objtool
validation and in particular the return sites in there due to
a warning which fires when an unpatched return thunk is being used
- Improve the NMI CPUs stall message to show additional information
about the state of each CPU wrt the NMI handler
- Enable gcc named address spaces support only on !KCSAN configs due to
compiler options incompatibility
- Revert a change which was trying to use GB pages for mapping regions
only when the regions would be large enough but that change lead to
kexec failing
- A documentation fixlet
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Merge tag 'x86_urgent_for_v6.9_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Borislav Petkov:
- Make sure single object builds in arch/x86/virt/ ala
make ... arch/x86/virt/vmx/tdx/seamcall.o
work again
- Do not do ROM range scans and memory validation when the kernel is
running as a SEV-SNP guest as those can get problematic and, before
that, are not really needed in such a guest
- Exclude the build-time generated vdso-image-x32.o object from objtool
validation and in particular the return sites in there due to a
warning which fires when an unpatched return thunk is being used
- Improve the NMI CPUs stall message to show additional information
about the state of each CPU wrt the NMI handler
- Enable gcc named address spaces support only on !KCSAN configs due to
compiler options incompatibility
- Revert a change which was trying to use GB pages for mapping regions
only when the regions would be large enough but that change lead to
kexec failing
- A documentation fixlet
* tag 'x86_urgent_for_v6.9_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/build: Use obj-y to descend into arch/x86/virt/
x86/sev: Skip ROM range scans and validation for SEV-SNP guests
x86/vdso: Fix rethunk patching for vdso-image-x32.o too
x86/nmi: Upgrade NMI backtrace stall checks & messages
x86/percpu: Disable named address spaces for KCSAN
Revert "x86/mm/ident_map: Use gbpages only where full GB page should be mapped."
Documentation/x86: Fix title underline length
The original version of the mitigation would patch in the calls to the
untraining routines directly. That is, the alternative() in UNTRAIN_RET
will patch in the CALL to srso_alias_untrain_ret() directly.
However, even if commit e7c25c441e ("x86/cpu: Cleanup the untrain
mess") meant well in trying to clean up the situation, due to micro-
architectural reasons, the untraining routine srso_alias_untrain_ret()
must be the target of a CALL instruction and not of a JMP instruction as
it is done now.
Reshuffle the alternative macros to accomplish that.
Fixes: e7c25c441e ("x86/cpu: Cleanup the untrain mess")
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are regression reports[1][2] that crashkernel region on x86_64 can't
be added into iomem tree sometime. This causes the later failure of kdump
loading.
This happened after commit 4a693ce65b ("kdump: defer the insertion of
crashkernel resources") was merged.
Even though, these reported issues are proved to be related to other
component, they are just exposed after above commmit applied, I still
would like to keep crashk_res and crashk_low_res being added into iomem
early as before because the early adding has been always there on x86_64
and working very well. For safety of kdump, Let's change it back.
Here, add a macro HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY to limit that
only ARCH defining the macro can have the early adding
crashk_res/_low_res into iomem. Then define
HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY on x86 to enable it.
Note: In reserve_crashkernel_low(), there's a remnant of crashk_low_res
handling which was mistakenly added back in commit 85fcde402d ("kexec:
split crashkernel reservation code out from crash_core.c").
[1]
[PATCH V2] x86/kexec: do not update E820 kexec table for setup_data
https://lore.kernel.org/all/Zfv8iCL6CT2JqLIC@darkstar.users.ipa.redhat.com/T/#u
[2]
Question about Address Range Validation in Crash Kernel Allocation
https://lore.kernel.org/all/4eeac1f733584855965a2ea62fa4da58@huawei.com/T/#u
Link: https://lkml.kernel.org/r/ZgDYemRQ2jxjLkq+@MiWiFi-R3L-srv
Fixes: 4a693ce65b ("kdump: defer the insertion of crashkernel resources")
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Huacai Chen <chenhuacai@loongson.cn>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Bohac <jbohac@suse.cz>
Cc: Li Huafei <lihuafei1@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SEV-SNP requires encrypted memory to be validated before access.
Because the ROM memory range is not part of the e820 table, it is not
pre-validated by the BIOS. Therefore, if a SEV-SNP guest kernel wishes
to access this range, the guest must first validate the range.
The current SEV-SNP code does indeed scan the ROM range during early
boot and thus attempts to validate the ROM range in probe_roms().
However, this behavior is neither sufficient nor necessary for the
following reasons:
* With regards to sufficiency, if EFI_CONFIG_TABLES are not enabled and
CONFIG_DMI_SCAN_MACHINE_NON_EFI_FALLBACK is set, the kernel will
attempt to access the memory at SMBIOS_ENTRY_POINT_SCAN_START (which
falls in the ROM range) prior to validation.
For example, Project Oak Stage 0 provides a minimal guest firmware
that currently meets these configuration conditions, meaning guests
booting atop Oak Stage 0 firmware encounter a problematic call chain
during dmi_setup() -> dmi_scan_machine() that results in a crash
during boot if SEV-SNP is enabled.
* With regards to necessity, SEV-SNP guests generally read garbage
(which changes across boots) from the ROM range, meaning these scans
are unnecessary. The guest reads garbage because the legacy ROM range
is unencrypted data but is accessed via an encrypted PMD during early
boot (where the PMD is marked as encrypted due to potentially mapping
actually-encrypted data in other PMD-contained ranges).
In one exceptional case, EISA probing treats the ROM range as
unencrypted data, which is inconsistent with other probing.
Continuing to allow SEV-SNP guests to use garbage and to inconsistently
classify ROM range encryption status can trigger undesirable behavior.
For instance, if garbage bytes appear to be a valid signature, memory
may be unnecessarily reserved for the ROM range. Future code or other
use cases may result in more problematic (arbitrary) behavior that
should be avoided.
While one solution would be to overhaul the early PMD mapping to always
treat the ROM region of the PMD as unencrypted, SEV-SNP guests do not
currently rely on data from the ROM region during early boot (and even
if they did, they would be mostly relying on garbage data anyways).
As a simpler solution, skip the ROM range scans (and the otherwise-
necessary range validation) during SEV-SNP guest early boot. The
potential SEV-SNP guest crash due to lack of ROM range validation is
thus avoided by simply not accessing the ROM range.
In most cases, skip the scans by overriding problematic x86_init
functions during sme_early_init() to SNP-safe variants, which can be
likened to x86_init overrides done for other platforms (ex: Xen); such
overrides also avoid the spread of cc_platform_has() checks throughout
the tree.
In the exceptional EISA case, still use cc_platform_has() for the
simplest change, given (1) checks for guest type (ex: Xen domain status)
are already performed here, and (2) these checks occur in a subsys
initcall instead of an x86_init function.
[ bp: Massage commit message, remove "we"s. ]
Fixes: 9704c07bf9 ("x86/kernel: Validate ROM memory before accessing when SEV-SNP is active")
Signed-off-by: Kevin Loughlin <kevinloughlin@google.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/20240313121546.2964854-1-kevinloughlin@google.com
Currently, the LBR code assumes that LBR Freeze is supported on all processors
when X86_FEATURE_AMD_LBR_V2 is available i.e. CPUID leaf 0x80000022[EAX]
bit 1 is set. This is incorrect as the availability of the feature is
additionally dependent on CPUID leaf 0x80000022[EAX] bit 2 being set,
which may not be set for all Zen 4 processors.
Define a new feature bit for LBR and PMC freeze and set the freeze enable bit
(FLBRI) in DebugCtl (MSR 0x1d9) conditionally.
It should still be possible to use LBR without freeze for profile-guided
optimization of user programs by using an user-only branch filter during
profiling. When the user-only filter is enabled, branches are no longer
recorded after the transition to CPL 0 upon PMI arrival. When branch
entries are read in the PMI handler, the branch stack does not change.
E.g.
$ perf record -j any,u -e ex_ret_brn_tkn ./workload
Since the feature bit is visible under flags in /proc/cpuinfo, it can be
used to determine the feasibility of use-cases which require LBR Freeze
to be supported by the hardware such as profile-guided optimization of
kernels.
Fixes: ca5b7c0d96 ("perf/x86/amd/lbr: Add LbrExtV2 branch record support")
Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/69a453c97cfd11c6f2584b19f937fe6df741510f.1711091584.git.sandipan.das@amd.com
- Ensure that the encryption mask at boot is properly propagated on
5-level page tables, otherwise the PGD entry is incorrectly set to
non-encrypted, which causes system crashes during boot.
- Undo the deferred 5-level page table setup as it cannot work with
memory encryption enabled.
- Prevent inconsistent XFD state on CPU hotplug, where the MSR is reset
to the default value but the cached variable is not, so subsequent
comparisons might yield the wrong result and as a consequence the
result prevents updating the MSR.
- Register the local APIC address only once in the MPPARSE enumeration to
prevent triggering the related WARN_ONs() in the APIC and topology code.
- Handle the case where no APIC is found gracefully by registering a fake
APIC in the topology code. That makes all related topology functions
work correctly and does not affect the actual APIC driver code at all.
- Don't evaluate logical IDs during early boot as the local APIC IDs are
not yet enumerated and the invoked function returns an error
code. Nothing requires the logical IDs before the final CPUID
enumeration takes place, which happens after the enumeration.
- Cure the fallout of the per CPU rework on UP which misplaced the
copying of boot_cpu_data to per CPU data so that the final update to
boot_cpu_data got lost which caused inconsistent state and boot
crashes.
- Use copy_from_kernel_nofault() in the kprobes setup as there is no
guarantee that the address can be safely accessed.
- Reorder struct members in struct saved_context to work around another
kmemleak false positive
- Remove the buggy code which tries to update the E820 kexec table for
setup_data as that is never passed to the kexec kernel.
- Update the resource control documentation to use the proper units.
- Fix a Kconfig warning observed with tinyconfig
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Merge tag 'x86-urgent-2024-03-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Thomas Gleixner:
- Ensure that the encryption mask at boot is properly propagated on
5-level page tables, otherwise the PGD entry is incorrectly set to
non-encrypted, which causes system crashes during boot.
- Undo the deferred 5-level page table setup as it cannot work with
memory encryption enabled.
- Prevent inconsistent XFD state on CPU hotplug, where the MSR is reset
to the default value but the cached variable is not, so subsequent
comparisons might yield the wrong result and as a consequence the
result prevents updating the MSR.
- Register the local APIC address only once in the MPPARSE enumeration
to prevent triggering the related WARN_ONs() in the APIC and topology
code.
- Handle the case where no APIC is found gracefully by registering a
fake APIC in the topology code. That makes all related topology
functions work correctly and does not affect the actual APIC driver
code at all.
- Don't evaluate logical IDs during early boot as the local APIC IDs
are not yet enumerated and the invoked function returns an error
code. Nothing requires the logical IDs before the final CPUID
enumeration takes place, which happens after the enumeration.
- Cure the fallout of the per CPU rework on UP which misplaced the
copying of boot_cpu_data to per CPU data so that the final update to
boot_cpu_data got lost which caused inconsistent state and boot
crashes.
- Use copy_from_kernel_nofault() in the kprobes setup as there is no
guarantee that the address can be safely accessed.
- Reorder struct members in struct saved_context to work around another
kmemleak false positive
- Remove the buggy code which tries to update the E820 kexec table for
setup_data as that is never passed to the kexec kernel.
- Update the resource control documentation to use the proper units.
- Fix a Kconfig warning observed with tinyconfig
* tag 'x86-urgent-2024-03-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/boot/64: Move 5-level paging global variable assignments back
x86/boot/64: Apply encryption mask to 5-level pagetable update
x86/cpu: Add model number for another Intel Arrow Lake mobile processor
x86/fpu: Keep xfd_state in sync with MSR_IA32_XFD
Documentation/x86: Document that resctrl bandwidth control units are MiB
x86/mpparse: Register APIC address only once
x86/topology: Handle the !APIC case gracefully
x86/topology: Don't evaluate logical IDs during early boot
x86/cpu: Ensure that CPU info updates are propagated on UP
kprobes/x86: Use copy_from_kernel_nofault() to read from unsafe address
x86/pm: Work around false positive kmemleak report in msr_build_context()
x86/kexec: Do not update E820 kexec table for setup_data
x86/config: Fix warning for 'make ARCH=x86_64 tinyconfig'
Since:
7ee18d6779 ("x86/power: Make restore_processor_context() sane")
kmemleak reports this issue:
unreferenced object 0xf68241e0 (size 32):
comm "swapper/0", pid 1, jiffies 4294668610 (age 68.432s)
hex dump (first 32 bytes):
00 cc cc cc 29 10 01 c0 00 00 00 00 00 00 00 00 ....)...........
00 42 82 f6 cc cc cc cc cc cc cc cc cc cc cc cc .B..............
backtrace:
[<461c1d50>] __kmem_cache_alloc_node+0x106/0x260
[<ea65e13b>] __kmalloc+0x54/0x160
[<c3858cd2>] msr_build_context.constprop.0+0x35/0x100
[<46635aff>] pm_check_save_msr+0x63/0x80
[<6b6bb938>] do_one_initcall+0x41/0x1f0
[<3f3add60>] kernel_init_freeable+0x199/0x1e8
[<3b538fde>] kernel_init+0x1a/0x110
[<938ae2b2>] ret_from_fork+0x1c/0x28
Which is a false positive.
Reproducer:
- Run rsync of whole kernel tree (multiple times if needed).
- start a kmemleak scan
- Note this is just an example: a lot of our internal tests hit these.
The root cause is similar to the fix in:
b0b592cf08 x86/pm: Fix false positive kmemleak report in msr_build_context()
ie. the alignment within the packed struct saved_context
which has everything unaligned as there is only "u16 gs;" at start of
struct where in the past there were four u16 there thus aligning
everything afterwards. The issue is with the fact that Kmemleak only
searches for pointers that are aligned (see how pointers are scanned in
kmemleak.c) so when the struct members are not aligned it doesn't see
them.
Testing:
We run a lot of tests with our CI, and after applying this fix we do not
see any kmemleak issues any more whilst without it we see hundreds of
the above report. From a single, simple test run consisting of 416 individual test
cases on kernel 5.10 x86 with kmemleak enabled we got 20 failures due to this,
which is quite a lot. With this fix applied we get zero kmemleak related failures.
Fixes: 7ee18d6779 ("x86/power: Make restore_processor_context() sane")
Signed-off-by: Anton Altaparmakov <anton@tuxera.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: stable@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20240314142656.17699-1-anton@tuxera.com
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Merge tag 'hyperv-next-signed-20240320' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux
Pull hyperv updates from Wei Liu:
- Use Hyper-V entropy to seed guest random number generator (Michael
Kelley)
- Convert to platform remove callback returning void for vmbus (Uwe
Kleine-König)
- Introduce hv_get_hypervisor_version function (Nuno Das Neves)
- Rename some HV_REGISTER_* defines for consistency (Nuno Das Neves)
- Change prefix of generic HV_REGISTER_* MSRs to HV_MSR_* (Nuno Das
Neves)
- Cosmetic changes for hv_spinlock.c (Purna Pavan Chandra Aekkaladevi)
- Use per cpu initial stack for vtl context (Saurabh Sengar)
* tag 'hyperv-next-signed-20240320' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
x86/hyperv: Use Hyper-V entropy to seed guest random number generator
x86/hyperv: Cosmetic changes for hv_spinlock.c
hyperv-tlfs: Rename some HV_REGISTER_* defines for consistency
hv: vmbus: Convert to platform remove callback returning void
mshyperv: Introduce hv_get_hypervisor_version function
x86/hyperv: Use per cpu initial stack for vtl context
hyperv-tlfs: Change prefix of generic HV_REGISTER_* MSRs to HV_MSR_*
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Merge tag 'for-linus-6.9-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from Juergen Gross:
- Xen event channel handling fix for a regression with a rare kernel
config and some added hardening
- better support of running Xen dom0 in PVH mode
- a cleanup for the xen grant-dma-iommu driver
* tag 'for-linus-6.9-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen/events: increment refcnt only if event channel is refcounted
xen/evtchn: avoid WARN() when unbinding an event channel
x86/xen: attempt to inflate the memory balloon on PVH
xen/grant-dma-iommu: Convert to platform remove callback returning void
The data structs for KVM_MEMORY_ENCRYPT_OP have different sizes for 32- and 64-bit
userspace, but they do not make any attempt to convert from one ABI to the other
when 32-bit userspace is running on 64-bit kernels. This configuration never
worked, and SEV is only for 64-bit kernels so we're not breaking ABI on 32-bit
kernels.
Fix this by adding the appropriate padding; no functional change intended
for 64-bit userspace.
Reviewed-by: Michael Roth <michael.roth@amd.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Delete kvm_vcpu_pv_apf_data.enabled to fix a goof in KVM's async #PF ABI where
the enabled field pushes the size of "struct kvm_vcpu_pv_apf_data" from 64 to
68 bytes, i.e. beyond a single cache line.
The enabled field is purely a guest-side flag that Linux-as-a-guest uses to
track whether or not the guest has enabled async #PF support. The actual flag
that is passed to the host, i.e. to KVM proper, is a single bit in a synthetic
MSR, MSR_KVM_ASYNC_PF_EN, i.e. is in a location completely unrelated to the
shared kvm_vcpu_pv_apf_data structure.
Simply drop the the field and use a dedicated guest-side per-CPU variable to
fix the ABI, as opposed to fixing the documentation to match reality. KVM has
never consumed kvm_vcpu_pv_apf_data.enabled, so the odds of the ABI change
breaking anything are extremely low.
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Merge tag 'kvm-x86-asyncpf_abi-6.9' of https://github.com/kvm-x86/linux into HEAD
Guest-side KVM async #PF ABI cleanup for 6.9
Delete kvm_vcpu_pv_apf_data.enabled to fix a goof in KVM's async #PF ABI where
the enabled field pushes the size of "struct kvm_vcpu_pv_apf_data" from 64 to
68 bytes, i.e. beyond a single cache line.
The enabled field is purely a guest-side flag that Linux-as-a-guest uses to
track whether or not the guest has enabled async #PF support. The actual flag
that is passed to the host, i.e. to KVM proper, is a single bit in a synthetic
MSR, MSR_KVM_ASYNC_PF_EN, i.e. is in a location completely unrelated to the
shared kvm_vcpu_pv_apf_data structure.
Simply drop the the field and use a dedicated guest-side per-CPU variable to
fix the ABI, as opposed to fixing the documentation to match reality. KVM has
never consumed kvm_vcpu_pv_apf_data.enabled, so the odds of the ABI change
breaking anything are extremely low.
* Changes to FPU handling came in via the main s390 pull request
* Only deliver to the guest the SCLP events that userspace has
requested.
* More virtual vs physical address fixes (only a cleanup since
virtual and physical address spaces are currently the same).
* Fix selftests undefined behavior.
x86:
* Fix a restriction that the guest can't program a PMU event whose
encoding matches an architectural event that isn't included in the
guest CPUID. The enumeration of an architectural event only says
that if a CPU supports an architectural event, then the event can be
programmed *using the architectural encoding*. The enumeration does
NOT say anything about the encoding when the CPU doesn't report support
the event *in general*. It might support it, and it might support it
using the same encoding that made it into the architectural PMU spec.
* Fix a variety of bugs in KVM's emulation of RDPMC (more details on
individual commits) and add a selftest to verify KVM correctly emulates
RDMPC, counter availability, and a variety of other PMC-related
behaviors that depend on guest CPUID and therefore are easier to
validate with selftests than with custom guests (aka kvm-unit-tests).
* Zero out PMU state on AMD if the virtual PMU is disabled, it does not
cause any bug but it wastes time in various cases where KVM would check
if a PMC event needs to be synthesized.
* Optimize triggering of emulated events, with a nice ~10% performance
improvement in VM-Exit microbenchmarks when a vPMU is exposed to the
guest.
* Tighten the check for "PMI in guest" to reduce false positives if an NMI
arrives in the host while KVM is handling an IRQ VM-Exit.
* Fix a bug where KVM would report stale/bogus exit qualification information
when exiting to userspace with an internal error exit code.
* Add a VMX flag in /proc/cpuinfo to report 5-level EPT support.
* Rework TDP MMU root unload, free, and alloc to run with mmu_lock held for
read, e.g. to avoid serializing vCPUs when userspace deletes a memslot.
* Tear down TDP MMU page tables at 4KiB granularity (used to be 1GiB). KVM
doesn't support yielding in the middle of processing a zap, and 1GiB
granularity resulted in multi-millisecond lags that are quite impolite
for CONFIG_PREEMPT kernels.
* Allocate write-tracking metadata on-demand to avoid the memory overhead when
a kernel is built with i915 virtualization support but the workloads use
neither shadow paging nor i915 virtualization.
* Explicitly initialize a variety of on-stack variables in the emulator that
triggered KMSAN false positives.
* Fix the debugregs ABI for 32-bit KVM.
* Rework the "force immediate exit" code so that vendor code ultimately decides
how and when to force the exit, which allowed some optimization for both
Intel and AMD.
* Fix a long-standing bug where kvm_has_noapic_vcpu could be left elevated if
vCPU creation ultimately failed, causing extra unnecessary work.
* Cleanup the logic for checking if the currently loaded vCPU is in-kernel.
* Harden against underflowing the active mmu_notifier invalidation
count, so that "bad" invalidations (usually due to bugs elsehwere in the
kernel) are detected earlier and are less likely to hang the kernel.
x86 Xen emulation:
* Overlay pages can now be cached based on host virtual address,
instead of guest physical addresses. This removes the need to
reconfigure and invalidate the cache if the guest changes the
gpa but the underlying host virtual address remains the same.
* When possible, use a single host TSC value when computing the deadline for
Xen timers in order to improve the accuracy of the timer emulation.
* Inject pending upcall events when the vCPU software-enables its APIC to fix
a bug where an upcall can be lost (and to follow Xen's behavior).
* Fall back to the slow path instead of warning if "fast" IRQ delivery of Xen
events fails, e.g. if the guest has aliased xAPIC IDs.
RISC-V:
* Support exception and interrupt handling in selftests
* New self test for RISC-V architectural timer (Sstc extension)
* New extension support (Ztso, Zacas)
* Support userspace emulation of random number seed CSRs.
ARM:
* Infrastructure for building KVM's trap configuration based on the
architectural features (or lack thereof) advertised in the VM's ID
registers
* Support for mapping vfio-pci BARs as Normal-NC (vaguely similar to
x86's WC) at stage-2, improving the performance of interacting with
assigned devices that can tolerate it
* Conversion of KVM's representation of LPIs to an xarray, utilized to
address serialization some of the serialization on the LPI injection
path
* Support for _architectural_ VHE-only systems, advertised through the
absence of FEAT_E2H0 in the CPU's ID register
* Miscellaneous cleanups, fixes, and spelling corrections to KVM and
selftests
LoongArch:
* Set reserved bits as zero in CPUCFG.
* Start SW timer only when vcpu is blocking.
* Do not restart SW timer when it is expired.
* Remove unnecessary CSR register saving during enter guest.
* Misc cleanups and fixes as usual.
Generic:
* cleanup Kconfig by removing CONFIG_HAVE_KVM, which was basically always
true on all architectures except MIPS (where Kconfig determines the
available depending on CPU capabilities). It is replaced either by
an architecture-dependent symbol for MIPS, and IS_ENABLED(CONFIG_KVM)
everywhere else.
* Factor common "select" statements in common code instead of requiring
each architecture to specify it
* Remove thoroughly obsolete APIs from the uapi headers.
* Move architecture-dependent stuff to uapi/asm/kvm.h
* Always flush the async page fault workqueue when a work item is being
removed, especially during vCPU destruction, to ensure that there are no
workers running in KVM code when all references to KVM-the-module are gone,
i.e. to prevent a very unlikely use-after-free if kvm.ko is unloaded.
* Grab a reference to the VM's mm_struct in the async #PF worker itself instead
of gifting the worker a reference, so that there's no need to remember
to *conditionally* clean up after the worker.
Selftests:
* Reduce boilerplate especially when utilize selftest TAP infrastructure.
* Add basic smoke tests for SEV and SEV-ES, along with a pile of library
support for handling private/encrypted/protected memory.
* Fix benign bugs where tests neglect to close() guest_memfd files.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm updates from Paolo Bonzini:
"S390:
- Changes to FPU handling came in via the main s390 pull request
- Only deliver to the guest the SCLP events that userspace has
requested
- More virtual vs physical address fixes (only a cleanup since
virtual and physical address spaces are currently the same)
- Fix selftests undefined behavior
x86:
- Fix a restriction that the guest can't program a PMU event whose
encoding matches an architectural event that isn't included in the
guest CPUID. The enumeration of an architectural event only says
that if a CPU supports an architectural event, then the event can
be programmed *using the architectural encoding*. The enumeration
does NOT say anything about the encoding when the CPU doesn't
report support the event *in general*. It might support it, and it
might support it using the same encoding that made it into the
architectural PMU spec
- Fix a variety of bugs in KVM's emulation of RDPMC (more details on
individual commits) and add a selftest to verify KVM correctly
emulates RDMPC, counter availability, and a variety of other
PMC-related behaviors that depend on guest CPUID and therefore are
easier to validate with selftests than with custom guests (aka
kvm-unit-tests)
- Zero out PMU state on AMD if the virtual PMU is disabled, it does
not cause any bug but it wastes time in various cases where KVM
would check if a PMC event needs to be synthesized
- Optimize triggering of emulated events, with a nice ~10%
performance improvement in VM-Exit microbenchmarks when a vPMU is
exposed to the guest
- Tighten the check for "PMI in guest" to reduce false positives if
an NMI arrives in the host while KVM is handling an IRQ VM-Exit
- Fix a bug where KVM would report stale/bogus exit qualification
information when exiting to userspace with an internal error exit
code
- Add a VMX flag in /proc/cpuinfo to report 5-level EPT support
- Rework TDP MMU root unload, free, and alloc to run with mmu_lock
held for read, e.g. to avoid serializing vCPUs when userspace
deletes a memslot
- Tear down TDP MMU page tables at 4KiB granularity (used to be
1GiB). KVM doesn't support yielding in the middle of processing a
zap, and 1GiB granularity resulted in multi-millisecond lags that
are quite impolite for CONFIG_PREEMPT kernels
- Allocate write-tracking metadata on-demand to avoid the memory
overhead when a kernel is built with i915 virtualization support
but the workloads use neither shadow paging nor i915 virtualization
- Explicitly initialize a variety of on-stack variables in the
emulator that triggered KMSAN false positives
- Fix the debugregs ABI for 32-bit KVM
- Rework the "force immediate exit" code so that vendor code
ultimately decides how and when to force the exit, which allowed
some optimization for both Intel and AMD
- Fix a long-standing bug where kvm_has_noapic_vcpu could be left
elevated if vCPU creation ultimately failed, causing extra
unnecessary work
- Cleanup the logic for checking if the currently loaded vCPU is
in-kernel
- Harden against underflowing the active mmu_notifier invalidation
count, so that "bad" invalidations (usually due to bugs elsehwere
in the kernel) are detected earlier and are less likely to hang the
kernel
x86 Xen emulation:
- Overlay pages can now be cached based on host virtual address,
instead of guest physical addresses. This removes the need to
reconfigure and invalidate the cache if the guest changes the gpa
but the underlying host virtual address remains the same
- When possible, use a single host TSC value when computing the
deadline for Xen timers in order to improve the accuracy of the
timer emulation
- Inject pending upcall events when the vCPU software-enables its
APIC to fix a bug where an upcall can be lost (and to follow Xen's
behavior)
- Fall back to the slow path instead of warning if "fast" IRQ
delivery of Xen events fails, e.g. if the guest has aliased xAPIC
IDs
RISC-V:
- Support exception and interrupt handling in selftests
- New self test for RISC-V architectural timer (Sstc extension)
- New extension support (Ztso, Zacas)
- Support userspace emulation of random number seed CSRs
ARM:
- Infrastructure for building KVM's trap configuration based on the
architectural features (or lack thereof) advertised in the VM's ID
registers
- Support for mapping vfio-pci BARs as Normal-NC (vaguely similar to
x86's WC) at stage-2, improving the performance of interacting with
assigned devices that can tolerate it
- Conversion of KVM's representation of LPIs to an xarray, utilized
to address serialization some of the serialization on the LPI
injection path
- Support for _architectural_ VHE-only systems, advertised through
the absence of FEAT_E2H0 in the CPU's ID register
- Miscellaneous cleanups, fixes, and spelling corrections to KVM and
selftests
LoongArch:
- Set reserved bits as zero in CPUCFG
- Start SW timer only when vcpu is blocking
- Do not restart SW timer when it is expired
- Remove unnecessary CSR register saving during enter guest
- Misc cleanups and fixes as usual
Generic:
- Clean up Kconfig by removing CONFIG_HAVE_KVM, which was basically
always true on all architectures except MIPS (where Kconfig
determines the available depending on CPU capabilities). It is
replaced either by an architecture-dependent symbol for MIPS, and
IS_ENABLED(CONFIG_KVM) everywhere else
- Factor common "select" statements in common code instead of
requiring each architecture to specify it
- Remove thoroughly obsolete APIs from the uapi headers
- Move architecture-dependent stuff to uapi/asm/kvm.h
- Always flush the async page fault workqueue when a work item is
being removed, especially during vCPU destruction, to ensure that
there are no workers running in KVM code when all references to
KVM-the-module are gone, i.e. to prevent a very unlikely
use-after-free if kvm.ko is unloaded
- Grab a reference to the VM's mm_struct in the async #PF worker
itself instead of gifting the worker a reference, so that there's
no need to remember to *conditionally* clean up after the worker
Selftests:
- Reduce boilerplate especially when utilize selftest TAP
infrastructure
- Add basic smoke tests for SEV and SEV-ES, along with a pile of
library support for handling private/encrypted/protected memory
- Fix benign bugs where tests neglect to close() guest_memfd files"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (246 commits)
selftests: kvm: remove meaningless assignments in Makefiles
KVM: riscv: selftests: Add Zacas extension to get-reg-list test
RISC-V: KVM: Allow Zacas extension for Guest/VM
KVM: riscv: selftests: Add Ztso extension to get-reg-list test
RISC-V: KVM: Allow Ztso extension for Guest/VM
RISC-V: KVM: Forward SEED CSR access to user space
KVM: riscv: selftests: Add sstc timer test
KVM: riscv: selftests: Change vcpu_has_ext to a common function
KVM: riscv: selftests: Add guest helper to get vcpu id
KVM: riscv: selftests: Add exception handling support
LoongArch: KVM: Remove unnecessary CSR register saving during enter guest
LoongArch: KVM: Do not restart SW timer when it is expired
LoongArch: KVM: Start SW timer only when vcpu is blocking
LoongArch: KVM: Set reserved bits as zero in CPUCFG
KVM: selftests: Explicitly close guest_memfd files in some gmem tests
KVM: x86/xen: fix recursive deadlock in timer injection
KVM: pfncache: simplify locking and make more self-contained
KVM: x86/xen: remove WARN_ON_ONCE() with false positives in evtchn delivery
KVM: x86/xen: inject vCPU upcall vector when local APIC is enabled
KVM: x86/xen: improve accuracy of Xen timers
...
from hotplugged memory rather than only from main memory. Series
"implement "memmap on memory" feature on s390".
- More folio conversions from Matthew Wilcox in the series
"Convert memcontrol charge moving to use folios"
"mm: convert mm counter to take a folio"
- Chengming Zhou has optimized zswap's rbtree locking, providing
significant reductions in system time and modest but measurable
reductions in overall runtimes. The series is "mm/zswap: optimize the
scalability of zswap rb-tree".
- Chengming Zhou has also provided the series "mm/zswap: optimize zswap
lru list" which provides measurable runtime benefits in some
swap-intensive situations.
- And Chengming Zhou further optimizes zswap in the series "mm/zswap:
optimize for dynamic zswap_pools". Measured improvements are modest.
- zswap cleanups and simplifications from Yosry Ahmed in the series "mm:
zswap: simplify zswap_swapoff()".
- In the series "Add DAX ABI for memmap_on_memory", Vishal Verma has
contributed several DAX cleanups as well as adding a sysfs tunable to
control the memmap_on_memory setting when the dax device is hotplugged
as system memory.
- Johannes Weiner has added the large series "mm: zswap: cleanups",
which does that.
- More DAMON work from SeongJae Park in the series
"mm/damon: make DAMON debugfs interface deprecation unignorable"
"selftests/damon: add more tests for core functionalities and corner cases"
"Docs/mm/damon: misc readability improvements"
"mm/damon: let DAMOS feeds and tame/auto-tune itself"
- In the series "mm/mempolicy: weighted interleave mempolicy and sysfs
extension" Rakie Kim has developed a new mempolicy interleaving policy
wherein we allocate memory across nodes in a weighted fashion rather
than uniformly. This is beneficial in heterogeneous memory environments
appearing with CXL.
- Christophe Leroy has contributed some cleanup and consolidation work
against the ARM pagetable dumping code in the series "mm: ptdump:
Refactor CONFIG_DEBUG_WX and check_wx_pages debugfs attribute".
- Luis Chamberlain has added some additional xarray selftesting in the
series "test_xarray: advanced API multi-index tests".
- Muhammad Usama Anjum has reworked the selftest code to make its
human-readable output conform to the TAP ("Test Anything Protocol")
format. Amongst other things, this opens up the use of third-party
tools to parse and process out selftesting results.
- Ryan Roberts has added fork()-time PTE batching of THP ptes in the
series "mm/memory: optimize fork() with PTE-mapped THP". Mainly
targeted at arm64, this significantly speeds up fork() when the process
has a large number of pte-mapped folios.
- David Hildenbrand also gets in on the THP pte batching game in his
series "mm/memory: optimize unmap/zap with PTE-mapped THP". It
implements batching during munmap() and other pte teardown situations.
The microbenchmark improvements are nice.
- And in the series "Transparent Contiguous PTEs for User Mappings" Ryan
Roberts further utilizes arm's pte's contiguous bit ("contpte
mappings"). Kernel build times on arm64 improved nicely. Ryan's series
"Address some contpte nits" provides some followup work.
- In the series "mm/hugetlb: Restore the reservation" Breno Leitao has
fixed an obscure hugetlb race which was causing unnecessary page faults.
He has also added a reproducer under the selftest code.
- In the series "selftests/mm: Output cleanups for the compaction test",
Mark Brown did what the title claims.
- Kinsey Ho has added the series "mm/mglru: code cleanup and refactoring".
- Even more zswap material from Nhat Pham. The series "fix and extend
zswap kselftests" does as claimed.
- In the series "Introduce cpu_dcache_is_aliasing() to fix DAX
regression" Mathieu Desnoyers has cleaned up and fixed rather a mess in
our handling of DAX on archiecctures which have virtually aliasing data
caches. The arm architecture is the main beneficiary.
- Lokesh Gidra's series "per-vma locks in userfaultfd" provides dramatic
improvements in worst-case mmap_lock hold times during certain
userfaultfd operations.
- Some page_owner enhancements and maintenance work from Oscar Salvador
in his series
"page_owner: print stacks and their outstanding allocations"
"page_owner: Fixup and cleanup"
- Uladzislau Rezki has contributed some vmalloc scalability improvements
in his series "Mitigate a vmap lock contention". It realizes a 12x
improvement for a certain microbenchmark.
- Some kexec/crash cleanup work from Baoquan He in the series "Split
crash out from kexec and clean up related config items".
- Some zsmalloc maintenance work from Chengming Zhou in the series
"mm/zsmalloc: fix and optimize objects/page migration"
"mm/zsmalloc: some cleanup for get/set_zspage_mapping()"
- Zi Yan has taught the MM to perform compaction on folios larger than
order=0. This a step along the path to implementaton of the merging of
large anonymous folios. The series is named "Enable >0 order folio
memory compaction".
- Christoph Hellwig has done quite a lot of cleanup work in the
pagecache writeback code in his series "convert write_cache_pages() to
an iterator".
- Some modest hugetlb cleanups and speedups in Vishal Moola's series
"Handle hugetlb faults under the VMA lock".
- Zi Yan has changed the page splitting code so we can split huge pages
into sizes other than order-0 to better utilize large folios. The
series is named "Split a folio to any lower order folios".
- David Hildenbrand has contributed the series "mm: remove
total_mapcount()", a cleanup.
- Matthew Wilcox has sought to improve the performance of bulk memory
freeing in his series "Rearrange batched folio freeing".
- Gang Li's series "hugetlb: parallelize hugetlb page init on boot"
provides large improvements in bootup times on large machines which are
configured to use large numbers of hugetlb pages.
- Matthew Wilcox's series "PageFlags cleanups" does that.
- Qi Zheng's series "minor fixes and supplement for ptdesc" does that
also. S390 is affected.
- Cleanups to our pagemap utility functions from Peter Xu in his series
"mm/treewide: Replace pXd_large() with pXd_leaf()".
- Nico Pache has fixed a few things with our hugepage selftests in his
series "selftests/mm: Improve Hugepage Test Handling in MM Selftests".
- Also, of course, many singleton patches to many things. Please see
the individual changelogs for details.
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Merge tag 'mm-stable-2024-03-13-20-04' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Sumanth Korikkar has taught s390 to allocate hotplug-time page frames
from hotplugged memory rather than only from main memory. Series
"implement "memmap on memory" feature on s390".
- More folio conversions from Matthew Wilcox in the series
"Convert memcontrol charge moving to use folios"
"mm: convert mm counter to take a folio"
- Chengming Zhou has optimized zswap's rbtree locking, providing
significant reductions in system time and modest but measurable
reductions in overall runtimes. The series is "mm/zswap: optimize the
scalability of zswap rb-tree".
- Chengming Zhou has also provided the series "mm/zswap: optimize zswap
lru list" which provides measurable runtime benefits in some
swap-intensive situations.
- And Chengming Zhou further optimizes zswap in the series "mm/zswap:
optimize for dynamic zswap_pools". Measured improvements are modest.
- zswap cleanups and simplifications from Yosry Ahmed in the series
"mm: zswap: simplify zswap_swapoff()".
- In the series "Add DAX ABI for memmap_on_memory", Vishal Verma has
contributed several DAX cleanups as well as adding a sysfs tunable to
control the memmap_on_memory setting when the dax device is
hotplugged as system memory.
- Johannes Weiner has added the large series "mm: zswap: cleanups",
which does that.
- More DAMON work from SeongJae Park in the series
"mm/damon: make DAMON debugfs interface deprecation unignorable"
"selftests/damon: add more tests for core functionalities and corner cases"
"Docs/mm/damon: misc readability improvements"
"mm/damon: let DAMOS feeds and tame/auto-tune itself"
- In the series "mm/mempolicy: weighted interleave mempolicy and sysfs
extension" Rakie Kim has developed a new mempolicy interleaving
policy wherein we allocate memory across nodes in a weighted fashion
rather than uniformly. This is beneficial in heterogeneous memory
environments appearing with CXL.
- Christophe Leroy has contributed some cleanup and consolidation work
against the ARM pagetable dumping code in the series "mm: ptdump:
Refactor CONFIG_DEBUG_WX and check_wx_pages debugfs attribute".
- Luis Chamberlain has added some additional xarray selftesting in the
series "test_xarray: advanced API multi-index tests".
- Muhammad Usama Anjum has reworked the selftest code to make its
human-readable output conform to the TAP ("Test Anything Protocol")
format. Amongst other things, this opens up the use of third-party
tools to parse and process out selftesting results.
- Ryan Roberts has added fork()-time PTE batching of THP ptes in the
series "mm/memory: optimize fork() with PTE-mapped THP". Mainly
targeted at arm64, this significantly speeds up fork() when the
process has a large number of pte-mapped folios.
- David Hildenbrand also gets in on the THP pte batching game in his
series "mm/memory: optimize unmap/zap with PTE-mapped THP". It
implements batching during munmap() and other pte teardown
situations. The microbenchmark improvements are nice.
- And in the series "Transparent Contiguous PTEs for User Mappings"
Ryan Roberts further utilizes arm's pte's contiguous bit ("contpte
mappings"). Kernel build times on arm64 improved nicely. Ryan's
series "Address some contpte nits" provides some followup work.
- In the series "mm/hugetlb: Restore the reservation" Breno Leitao has
fixed an obscure hugetlb race which was causing unnecessary page
faults. He has also added a reproducer under the selftest code.
- In the series "selftests/mm: Output cleanups for the compaction
test", Mark Brown did what the title claims.
- Kinsey Ho has added the series "mm/mglru: code cleanup and
refactoring".
- Even more zswap material from Nhat Pham. The series "fix and extend
zswap kselftests" does as claimed.
- In the series "Introduce cpu_dcache_is_aliasing() to fix DAX
regression" Mathieu Desnoyers has cleaned up and fixed rather a mess
in our handling of DAX on archiecctures which have virtually aliasing
data caches. The arm architecture is the main beneficiary.
- Lokesh Gidra's series "per-vma locks in userfaultfd" provides
dramatic improvements in worst-case mmap_lock hold times during
certain userfaultfd operations.
- Some page_owner enhancements and maintenance work from Oscar Salvador
in his series
"page_owner: print stacks and their outstanding allocations"
"page_owner: Fixup and cleanup"
- Uladzislau Rezki has contributed some vmalloc scalability
improvements in his series "Mitigate a vmap lock contention". It
realizes a 12x improvement for a certain microbenchmark.
- Some kexec/crash cleanup work from Baoquan He in the series "Split
crash out from kexec and clean up related config items".
- Some zsmalloc maintenance work from Chengming Zhou in the series
"mm/zsmalloc: fix and optimize objects/page migration"
"mm/zsmalloc: some cleanup for get/set_zspage_mapping()"
- Zi Yan has taught the MM to perform compaction on folios larger than
order=0. This a step along the path to implementaton of the merging
of large anonymous folios. The series is named "Enable >0 order folio
memory compaction".
- Christoph Hellwig has done quite a lot of cleanup work in the
pagecache writeback code in his series "convert write_cache_pages()
to an iterator".
- Some modest hugetlb cleanups and speedups in Vishal Moola's series
"Handle hugetlb faults under the VMA lock".
- Zi Yan has changed the page splitting code so we can split huge pages
into sizes other than order-0 to better utilize large folios. The
series is named "Split a folio to any lower order folios".
- David Hildenbrand has contributed the series "mm: remove
total_mapcount()", a cleanup.
- Matthew Wilcox has sought to improve the performance of bulk memory
freeing in his series "Rearrange batched folio freeing".
- Gang Li's series "hugetlb: parallelize hugetlb page init on boot"
provides large improvements in bootup times on large machines which
are configured to use large numbers of hugetlb pages.
- Matthew Wilcox's series "PageFlags cleanups" does that.
- Qi Zheng's series "minor fixes and supplement for ptdesc" does that
also. S390 is affected.
- Cleanups to our pagemap utility functions from Peter Xu in his series
"mm/treewide: Replace pXd_large() with pXd_leaf()".
- Nico Pache has fixed a few things with our hugepage selftests in his
series "selftests/mm: Improve Hugepage Test Handling in MM
Selftests".
- Also, of course, many singleton patches to many things. Please see
the individual changelogs for details.
* tag 'mm-stable-2024-03-13-20-04' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (435 commits)
mm/zswap: remove the memcpy if acomp is not sleepable
crypto: introduce: acomp_is_async to expose if comp drivers might sleep
memtest: use {READ,WRITE}_ONCE in memory scanning
mm: prohibit the last subpage from reusing the entire large folio
mm: recover pud_leaf() definitions in nopmd case
selftests/mm: skip the hugetlb-madvise tests on unmet hugepage requirements
selftests/mm: skip uffd hugetlb tests with insufficient hugepages
selftests/mm: dont fail testsuite due to a lack of hugepages
mm/huge_memory: skip invalid debugfs new_order input for folio split
mm/huge_memory: check new folio order when split a folio
mm, vmscan: retry kswapd's priority loop with cache_trim_mode off on failure
mm: add an explicit smp_wmb() to UFFDIO_CONTINUE
mm: fix list corruption in put_pages_list
mm: remove folio from deferred split list before uncharging it
filemap: avoid unnecessary major faults in filemap_fault()
mm,page_owner: drop unnecessary check
mm,page_owner: check for null stack_record before bumping its refcount
mm: swap: fix race between free_swap_and_cache() and swapoff()
mm/treewide: align up pXd_leaf() retval across archs
mm/treewide: drop pXd_large()
...
- Measure initrd and command line using the CC protocol if the ordinary
TCG2 protocol is not implemented, typically on TDX confidential VMs
- Avoid creating mappings that are both writable and executable while
running in the EFI boot services. This is a prerequisite for getting
the x86 shim loader signed by MicroSoft again, which allows the
distros to install on x86 PCs that ship with EFI secure boot enabled.
- API update for struct platform_driver::remove()
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Merge tag 'efi-next-for-v6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi
Pull EFI updates from Ard Biesheuvel:
- Measure initrd and command line using the CC protocol if the ordinary
TCG2 protocol is not implemented, typically on TDX confidential VMs
- Avoid creating mappings that are both writable and executable while
running in the EFI boot services. This is a prerequisite for getting
the x86 shim loader signed by MicroSoft again, which allows the
distros to install on x86 PCs that ship with EFI secure boot enabled.
- API update for struct platform_driver::remove()
* tag 'efi-next-for-v6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
virt: efi_secret: Convert to platform remove callback returning void
x86/efistub: Remap kernel text read-only before dropping NX attribute
efi/libstub: Add get_event_log() support for CC platforms
efi/libstub: Measure into CC protocol if TCG2 protocol is absent
efi/libstub: Add Confidential Computing (CC) measurement typedefs
efi/tpm: Use symbolic GUID name from spec for final events table
efi/libstub: Use TPM event typedefs from the TCG PC Client spec
When running as PVH or HVM Linux will use holes in the memory map as scratch
space to map grants, foreign domain pages and possibly miscellaneous other
stuff. However the usage of such memory map holes for Xen purposes can be
problematic. The request of holesby Xen happen quite early in the kernel boot
process (grant table setup already uses scratch map space), and it's possible
that by then not all devices have reclaimed their MMIO space. It's not
unlikely for chunks of Xen scratch map space to end up using PCI bridge MMIO
window memory, which (as expected) causes quite a lot of issues in the system.
At least for PVH dom0 we have the possibility of using regions marked as
UNUSABLE in the e820 memory map. Either if the region is UNUSABLE in the
native memory map, or it has been converted into UNUSABLE in order to hide RAM
regions from dom0, the second stage translation page-tables can populate those
areas without issues.
PV already has this kind of logic, where the balloon driver is inflated at
boot. Re-use the current logic in order to also inflate it when running as
PVH. onvert UNUSABLE regions up to the ratio specified in EXTRA_MEM_RATIO to
RAM, while reserving them using xen_add_extra_mem() (which is also moved so
it's no longer tied to CONFIG_PV).
[jgross: fixed build for CONFIG_PVH without CONFIG_XEN_PVH]
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20240220174341.56131-1-roger.pau@citrix.com
Signed-off-by: Juergen Gross <jgross@suse.com>
- string.h and related header cleanups (Tanzir Hasan, Andy Shevchenko)
- VMCI memcpy() usage and struct_size() cleanups (Vasiliy Kovalev, Harshit
Mogalapalli)
- selftests/powerpc: Fix load_unaligned_zeropad build failure (Michael
Ellerman)
- hardened Kconfig fragment updates (Marco Elver, Lukas Bulwahn)
- Handle tail call optimization better in LKDTM (Douglas Anderson)
- Use long form types in overflow.h (Andy Shevchenko)
- Add flags param to string_get_size() (Andy Shevchenko)
- Add Coccinelle script for potential struct_size() use (Jacob Keller)
- Fix objtool corner case under KCFI (Josh Poimboeuf)
- Drop 13 year old backward compat CAP_SYS_ADMIN check (Jingzi Meng)
- Add str_plural() helper (Michal Wajdeczko, Kees Cook)
- Ignore relocations in .notes section
- Add comments to explain how __is_constexpr() works
- Fix m68k stack alignment expectations in stackinit Kunit test
- Convert string selftests to KUnit
- Add KUnit tests for fortified string functions
- Improve reporting during fortified string warnings
- Allow non-type arg to type_max() and type_min()
- Allow strscpy() to be called with only 2 arguments
- Add binary mode to leaking_addresses scanner
- Various small cleanups to leaking_addresses scanner
- Adding wrapping_*() arithmetic helper
- Annotate initial signed integer wrap-around in refcount_t
- Add explicit UBSAN section to MAINTAINERS
- Fix UBSAN self-test warnings
- Simplify UBSAN build via removal of CONFIG_UBSAN_SANITIZE_ALL
- Reintroduce UBSAN's signed overflow sanitizer
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Merge tag 'hardening-v6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull hardening updates from Kees Cook:
"As is pretty normal for this tree, there are changes all over the
place, especially for small fixes, selftest improvements, and improved
macro usability.
Some header changes ended up landing via this tree as they depended on
the string header cleanups. Also, a notable set of changes is the work
for the reintroduction of the UBSAN signed integer overflow sanitizer
so that we can continue to make improvements on the compiler side to
make this sanitizer a more viable future security hardening option.
Summary:
- string.h and related header cleanups (Tanzir Hasan, Andy
Shevchenko)
- VMCI memcpy() usage and struct_size() cleanups (Vasiliy Kovalev,
Harshit Mogalapalli)
- selftests/powerpc: Fix load_unaligned_zeropad build failure
(Michael Ellerman)
- hardened Kconfig fragment updates (Marco Elver, Lukas Bulwahn)
- Handle tail call optimization better in LKDTM (Douglas Anderson)
- Use long form types in overflow.h (Andy Shevchenko)
- Add flags param to string_get_size() (Andy Shevchenko)
- Add Coccinelle script for potential struct_size() use (Jacob
Keller)
- Fix objtool corner case under KCFI (Josh Poimboeuf)
- Drop 13 year old backward compat CAP_SYS_ADMIN check (Jingzi Meng)
- Add str_plural() helper (Michal Wajdeczko, Kees Cook)
- Ignore relocations in .notes section
- Add comments to explain how __is_constexpr() works
- Fix m68k stack alignment expectations in stackinit Kunit test
- Convert string selftests to KUnit
- Add KUnit tests for fortified string functions
- Improve reporting during fortified string warnings
- Allow non-type arg to type_max() and type_min()
- Allow strscpy() to be called with only 2 arguments
- Add binary mode to leaking_addresses scanner
- Various small cleanups to leaking_addresses scanner
- Adding wrapping_*() arithmetic helper
- Annotate initial signed integer wrap-around in refcount_t
- Add explicit UBSAN section to MAINTAINERS
- Fix UBSAN self-test warnings
- Simplify UBSAN build via removal of CONFIG_UBSAN_SANITIZE_ALL
- Reintroduce UBSAN's signed overflow sanitizer"
* tag 'hardening-v6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (51 commits)
selftests/powerpc: Fix load_unaligned_zeropad build failure
string: Convert helpers selftest to KUnit
string: Convert selftest to KUnit
sh: Fix build with CONFIG_UBSAN=y
compiler.h: Explain how __is_constexpr() works
overflow: Allow non-type arg to type_max() and type_min()
VMCI: Fix possible memcpy() run-time warning in vmci_datagram_invoke_guest_handler()
lib/string_helpers: Add flags param to string_get_size()
x86, relocs: Ignore relocations in .notes section
objtool: Fix UNWIND_HINT_{SAVE,RESTORE} across basic blocks
overflow: Use POD in check_shl_overflow()
lib: stackinit: Adjust target string to 8 bytes for m68k
sparc: vdso: Disable UBSAN instrumentation
kernel.h: Move lib/cmdline.c prototypes to string.h
leaking_addresses: Provide mechanism to scan binary files
leaking_addresses: Ignore input device status lines
leaking_addresses: Use File::Temp for /tmp files
MAINTAINERS: Update LEAKING_ADDRESSES details
fortify: Improve buffer overflow reporting
fortify: Add KUnit tests for runtime overflows
...
Just two small updates this time:
- A series I did to unify the definition of PAGE_SIZE through Kconfig,
intended to help with a vdso rework that needs the constant but
cannot include the normal kernel headers when building the compat
VDSO on arm64 and potentially others.
- a patch from Yan Zhao to remove the pfn_to_virt() definitions from
a couple of architectures after finding they were both incorrect
and entirely unused.
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Merge tag 'asm-generic-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic
Pull asm-generic updates from Arnd Bergmann:
"Just two small updates this time:
- A series I did to unify the definition of PAGE_SIZE through
Kconfig, intended to help with a vdso rework that needs the
constant but cannot include the normal kernel headers when building
the compat VDSO on arm64 and potentially others
- a patch from Yan Zhao to remove the pfn_to_virt() definitions from
a couple of architectures after finding they were both incorrect
and entirely unused"
* tag 'asm-generic-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
arch: define CONFIG_PAGE_SIZE_*KB on all architectures
arch: simplify architecture specific page size configuration
arch: consolidate existing CONFIG_PAGE_SIZE_*KB definitions
mm: Remove broken pfn_to_virt() on arch csky/hexagon/openrisc
- Continuing work by Ard Biesheuvel to improve the x86 early startup code,
with the long-term goal to make it position independent:
- Get rid of early accesses to global objects, either by moving them
to the stack, deferring the access until later, or dropping the
globals entirely.
- Move all code that runs early via the 1:1 mapping into .head.text,
and move code that does not out of it, so that build time checks can
be added later to ensure that no inadvertent absolute references were
emitted into code that does not tolerate them.
- Remove fixup_pointer() and occurrences of __pa_symbol(), which rely
on the compiler emitting absolute references, which is not guaranteed.
- Improve the early console code.
- Add early console message about ignored NMIs, so that users are at least
warned about their existence - even if we cannot do anything about them.
- Improve the kexec code's kernel load address handling.
- Enable more X86S (simplified x86) bits.
- Simplify early boot GDT handling
- Micro-optimize the boot code a bit
- Misc cleanups.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-boot-2024-03-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 boot updates from Ingo Molnar:
- Continuing work by Ard Biesheuvel to improve the x86 early startup
code, with the long-term goal to make it position independent:
- Get rid of early accesses to global objects, either by moving
them to the stack, deferring the access until later, or dropping
the globals entirely
- Move all code that runs early via the 1:1 mapping into
.head.text, and move code that does not out of it, so that build
time checks can be added later to ensure that no inadvertent
absolute references were emitted into code that does not
tolerate them
- Remove fixup_pointer() and occurrences of __pa_symbol(), which
rely on the compiler emitting absolute references, which is not
guaranteed
- Improve the early console code
- Add early console message about ignored NMIs, so that users are at
least warned about their existence - even if we cannot do anything
about them
- Improve the kexec code's kernel load address handling
- Enable more X86S (simplified x86) bits
- Simplify early boot GDT handling
- Micro-optimize the boot code a bit
- Misc cleanups
* tag 'x86-boot-2024-03-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits)
x86/sev: Move early startup code into .head.text section
x86/sme: Move early SME kernel encryption handling into .head.text
x86/boot: Move mem_encrypt= parsing to the decompressor
efi/libstub: Add generic support for parsing mem_encrypt=
x86/startup_64: Simplify virtual switch on primary boot
x86/startup_64: Simplify calculation of initial page table address
x86/startup_64: Defer assignment of 5-level paging global variables
x86/startup_64: Simplify CR4 handling in startup code
x86/boot: Use 32-bit XOR to clear registers
efi/x86: Set the PE/COFF header's NX compat flag unconditionally
x86/boot/64: Load the final kernel GDT during early boot directly, remove startup_gdt[]
x86/boot/64: Use RIP_REL_REF() to access early_top_pgt[]
x86/boot/64: Use RIP_REL_REF() to access early page tables
x86/boot/64: Use RIP_REL_REF() to access '__supported_pte_mask'
x86/boot/64: Use RIP_REL_REF() to access early_dynamic_pgts[]
x86/boot/64: Use RIP_REL_REF() to assign 'phys_base'
x86/boot/64: Simplify global variable accesses in GDT/IDT programming
x86/trampoline: Bypass compat mode in trampoline_start64() if not needed
kexec: Allocate kernel above bzImage's pref_address
x86/boot: Add a message about ignored early NMIs
...
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Merge tag 'x86-apic-2024-03-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 APIC fixup from Dave Hansen:
"Revert VERW fixed addressing patch.
The reverted commit is not x86/apic material and was cruft left over
from a merge.
I believe the sequence of events went something like this:
- The commit in question was added to x86/urgent
- x86/urgent was merged into x86/apic to resolve a conflict
- The commit was zapped from x86/urgent, but *not* from x86/apic
- x86/apic got pullled (yesterday)
I think we need to be a bit more vigilant when zapping things to make
sure none of the other branches are depending on the zapped material"
* tag 'x86-apic-2024-03-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Revert "x86/bugs: Use fixed addressing for VERW operand"
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Merge tag 'rfds-for-linus-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 RFDS mitigation from Dave Hansen:
"RFDS is a CPU vulnerability that may allow a malicious userspace to
infer stale register values from kernel space. Kernel registers can
have all kinds of secrets in them so the mitigation is basically to
wait until the kernel is about to return to userspace and has user
values in the registers. At that point there is little chance of
kernel secrets ending up in the registers and the microarchitectural
state can be cleared.
This leverages some recent robustness fixes for the existing MDS
vulnerability. Both MDS and RFDS use the VERW instruction for
mitigation"
* tag 'rfds-for-linus-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
KVM/x86: Export RFDS_NO and RFDS_CLEAR to guests
x86/rfds: Mitigate Register File Data Sampling (RFDS)
Documentation/hw-vuln: Add documentation for RFDS
x86/mmio: Disable KVM mitigation when X86_FEATURE_CLEAR_CPU_BUF is set
Linus Torvalds
Ashish Kalra
Kirill A. Shutemov
Paolo Bonzini
Mathieu Desnoyers
Sean Christopherson
Ingo Molnar
Pawan Gupta
Daniel Sneddon
Adam Dunlap
Borislav Petkov (AMD)
Jason A. Donenfeld
Joan Bruguera Micó
Baoquan He
Kevin Loughlin
Sandipan Das
Tony Luck
Anton Altaparmakov
Roger Pau Monne