linux.git/arch/x86/include, branch master

Merge tag 'x86-urgent-2026-05-31' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2026-05-31T15:52:16+00:00

Pull x86 fixes from Ingo Molnar:

 - Make the clearcpuid= boot parameter less prominent
   and warn about its dangers & caveats (Borislav Petkov)

 - Do not access the (new) PLATFORM_ID MSR when running
   as a guest (Borislav Petkov)

 - x86 ftrace: Relocate %rip-relative percpu refs in dynamic
   trampolines, to fix crash when using such trampolines
   (Alexis Lothoré)

 - Fix x86-64 CFI build error (Peter Zijlstra)

 - Revert FPU signal return magic number check optimization,
   because it broke CRIU and gVisor in certain FPU configurations
   (Andrei Vagin)

* tag 'x86-urgent-2026-05-31' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Revert "x86/fpu: Refine and simplify the magic number check during signal return"
  x86/kvm/vmx: Fix x86_64 CFI build
  x86/ftrace: Relocate %rip-relative percpu refs in dynamic trampolines
  x86/microcode: Do not access MSR_IA32_PLATFORM_ID when running as a guest
  Documentation/arch/x86: Hide clearcpuid=

Merge tag 'kvm-x86-fixes-7.1-rc6' of https://github.com/kvm-x86/linux into HEAD

2026-05-29T17:28:16+00:00

KVM x86 fixes for 7.1-rcN

 - Include the kernel's linux/mman.h in KVM selftests to ensure MADV_COLLAPSE
   is defined, as older libc versions may not provide it.

 - Include execinfo.h if and only if KVM selftests are building against glibc,
   and provide a test_dump_stack() for non-glibc builds.

 - Fudge around an RCU splat in the emegerncy reboot code that is technically
   a legitimate flaw, but in practice is a non-issue and fixing the flaw, e.g.
   by adding locking, would incur meaningful risk, i.e. do more harm than good.

 - Rate-limit global clock updates once again (but without delayed work), as
   KVM was subtly relying on the old rate-limiting for NPT correction to guard
   against "update storms" when running without a master clock on systems with
   overcommitted CPUs.

 - Fix a brown paper bag goof where KVM checked if ERAPS is "dirty" instead of
   marking it dirty when emulating INVPCID.

 - Flush the TLB when transitioning from xAVIC => x2AVIC to ensure the CPU TLB
   doesn't contain AVIC-tagged entries for the APIC base GPA.

x86/microcode: Do not access MSR_IA32_PLATFORM_ID when running as a guest

2026-05-26T20:36:23+00:00

Patch in Fixes: causes the usual:

  unchecked MSR access error: RDMSR from 0x17 at ... (intel_get_platform_id)
  Call Trace:
   early_init_intel
   early_cpu_init
   setup_arch
   _printk
   start_kernel
   x86_64_start_reservations
   x86_64_start_kernel
   common_startup_64

because the kernel is booted in a guest.

In order to avoid it, this MSR access needs to be prevented when running
virtualized. That is usually done by checking X86_FEATURE_HYPERVISOR but
for this particular case it is too early yet.

The platform ID needs to be read as early as when microcode is loaded on
the BSP:

  load_ucode_bsp ... -> get_microcode_blob ... -> intel_find_matching_signature

and by that time, CPUID leafs haven't been parsed yet.

The microcode loader already has logic to check early whether the kernel
is running virtualized so make that globally available to arch/x86/. The
query whether running virtualized is getting more and more prominent in
recent times so might as well make it an arch-global var which the rest
of the code can use.

Fixes: d8630b67ca1ed ("x86/cpu: Add platform ID to CPU info structure")
Reported-by: Vishal Verma 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Binbin Wu 
Reviewed-by: Xiaoyao Li 
Tested-by: Binbin Wu 
Link: https://lore.kernel.org/all/20260430020953.1405535-1-binbin.wu@linux.intel.com

Merge tag 'x86-urgent-2026-05-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2026-05-24T18:00:45+00:00

Pull x86 fixes from Ingo Molnar:

 - On SEV guests, handle set_memory_{encrypted,decrypted}() failures
   more conservatively by assuming that all affected pages are
   unencrypted (Carlos López)

 - Disable broadcast TLB flush when PCID is disabled (Tom Lendacky)

 - Fix VMX vs. hrtimer_rearm_deferred() regression (Peter Zijlstra)

 - Move IRQ/NMI dispatch code from KVM into x86 core, to prepare for a
   KVM x2apic fix (Peter Zijlstra)

 - Fix incorrect munmap() size on map_vdso() failure (Guilherme Giacomo
   Simoes)

* tag 'x86-urgent-2026-05-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  virt: sev-guest: Explicitly leak pages in unknown state
  x86/mm: Disable broadcast TLB flush when PCID is disabled
  x86/kvm/vmx: Fix VMX vs hrtimer_rearm_deferred()
  x86/kvm/vmx: Move IRQ/NMI dispatch from KVM into x86 core
  x86/vdso: Fix incorrect size in munmap() on map_vdso() failure

ring-buffer: Flush and stop persistent ring buffer on panic

2026-05-21T12:20:58+00:00

On real hardware, panic and machine reboot may not flush hardware cache
to memory. This means the persistent ring buffer, which relies on a
coherent state of memory, may not have its events written to the buffer
and they may be lost. Moreover, there may be inconsistency with the
counters which are used for validation of the integrity of the
persistent ring buffer which may cause all data to be discarded.

To avoid this issue, stop recording of the ring buffer on panic and
flush the cache of the ring buffer's memory.

Fixes: e645535a954a ("tracing: Add option to use memmapped memory for trace boot instance")
Cc: stable@vger.kernel.org
Cc: Will Deacon 
Cc: Mathieu Desnoyers 
Cc: Ian Rogers 
Link: https://patch.msgid.link/177751969602.2136606.12031934362587643488.stgit@mhiramat.tok.corp.google.com
Signed-off-by: Masami Hiramatsu (Google) 
Acked-by: Catalin Marinas 
Acked-by: Geert Uytterhoeven 
Signed-off-by: Steven Rostedt

x86/kvm/vmx: Move IRQ/NMI dispatch from KVM into x86 core

2026-05-19T18:25:51+00:00

Move the VMX interrupt dispatch magic into the x86 core code. This
isolates KVM from the FRED/IDT decisions and reduces the amount of
EXPORT_SYMBOL_FOR_KVM().

Suggested-by: Sean Christopherson 
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Thomas Gleixner 
Tested-by: "Verma, Vishal L" 
Tested-by: Zhao Liu 
Tested-by: Zhao Liu 
Tested-by: Sean Christopherson 
Reviewed-by: Binbin Wu 
Acked-by: Sean Christopherson 
Link: https://patch.msgid.link/20260508091829.GO3126523@noisy.programming.kicks-ass.net

KVM: x86: Rate-limit global clock updates on vCPU load

2026-05-13T16:57:44+00:00

commit 446fcce2a52b ("Revert "x86: kvm: rate-limit global clock updates"")
dropped the rate limiting for KVM_REQ_GLOBAL_CLOCK_UPDATE.

As a result, kvm_arch_vcpu_load() can queue global clock update requests
every time a vCPU is scheduled when the master clock is disabled or when
the vCPU is loaded for the first time.

Restore the throttling with a per-VM ratelimit state and gate
KVM_REQ_GLOBAL_CLOCK_UPDATE through __ratelimit(), so frequent vCPU
scheduling does not generate a steady stream of redundant clock update
requests.

Fixes: 446fcce2a52b ("Revert "x86: kvm: rate-limit global clock updates"")
Signed-off-by: Lei Chen 
Reported-by: Jaroslav Pulchart 
Closes: https://lore.kernel.org/all/CAK8fFZ5gY8_Mw2A=iZVFNVKQNrXQzVsn-HTd+Me9K6ZfmdgA+Q@mail.gmail.com/
Link: https://patch.msgid.link/20260409142226.2581-1-lei.chen@smartx.com
Signed-off-by: Sean Christopherson

x86/CPU/AMD: Prevent improper isolation of shared resources in Zen2's op cache

2026-05-12T03:06:36+00:00

Make sure resources are not improperly shared in the op cache and
cause instruction corruption this way.

Signed-off-by: Prathyushi Nangia 
Co-developed-by: Borislav Petkov (AMD) 
Signed-off-by: Borislav Petkov (AMD) 
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds

x86/efi: Restore IRQ state in EFI page fault handler

2026-05-05T07:31:28+00:00

The kernel's softirq API does not permit re-enabling softirqs while IRQs
are disabled. The reason for this is that local_bh_enable() will not
only re-enable delivery of softirqs over the back of IRQs, it will also
handle any pending softirqs immediately, regardless of whether IRQs are
enabled at that point.

For this reason, commit

  d02198550423 ("x86/fpu: Improve crypto performance by making kernel-mode FPU reliably usable in softirqs")

disables softirqs only when IRQs are enabled, as it is not permitted
otherwise, but also unnecessary, given that asynchronous softirq
delivery never happens to begin with while IRQs are disabled.

However, this does mean that entering a kernel mode FPU section with
IRQs enabled and leaving it with IRQs disabled leads to problems, as
identified by Sashiko [0]: the EFI page fault handler is called from
page_fault_oops() with IRQs disabled, and thus ends the kernel mode FPU
section with IRQs disabled as well, regardless of whether IRQs were
enabled when it was started. This may result in schedule() being called
with a non-zero preempt_count, causing a BUG().

So take care to re-enable IRQs when handling any EFI page faults if they
were taken with IRQs enabled.

[0] https://sashiko.dev/#/patchset/20260430074107.27051-1-ivan.hu%40canonical.com

Cc: Eric Biggers 
Cc: Ivan Hu 
Cc: x86@kernel.org
Cc: 
Fixes: d02198550423 ("x86/fpu: Improve crypto performance by making kernel-mode FPU reliably usable in softirqs")
Reviewed-by: Eric Biggers 
Signed-off-by: Ard Biesheuvel

Merge tag 's390-7.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2026-04-22T18:13:45+00:00

Pull s390 updates from Vasily Gorbik:

 - Add support for CONFIG_PAGE_TABLE_CHECK and enable it in
   debug_defconfig. s390 can only tell user from kernel PTEs via the mm,
   so mm_struct is now passed into pxx_user_accessible_page() callbacks

 - Expose the PCI function UID as an arch-specific slot attribute in
   sysfs so a function can be identified by its user-defined id while
   still in standby. Introduces a generic ARCH_PCI_SLOT_GROUPS hook in
   drivers/pci/slot.c

 - Refresh s390 PCI documentation to reflect current behavior and cover
   previously undocumented sysfs attributes

 - zcrypt device driver cleanup series: consistent field types, clearer
   variable naming, a kernel-doc warning fix, and a comment explaining
   the intentional synchronize_rcu() in pkey_handler_register()

 - Provide an s390 arch_raw_cpu_ptr() that avoids the detour via
   get_lowcore() using alternatives, shrinking defconfig by ~27 kB

 - Guard identity-base randomization with kaslr_enabled() so nokaslr
   keeps the identity mapping at 0 even with RANDOMIZE_IDENTITY_BASE=y

 - Build S390_MODULES_SANITY_TEST as a module only by requiring KUNIT &&
   m, since built-in would not exercise module loading

 - Remove the permanently commented-out HMCDRV_DEV_CLASS create_class()
   code in the hmcdrv driver

 - Drop stale ident_map_size extern conflicting with asm/page.h

* tag 's390-7.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/zcrypt: Fix warning about wrong kernel doc comment
  PCI: s390: Expose the UID as an arch specific PCI slot attribute
  docs: s390/pci: Improve and update PCI documentation
  s390/pkey: Add comment about synchronize_rcu() to pkey base
  s390/hmcdrv: Remove commented out code
  s390/zcrypt: Slight rework on the agent_id field
  s390/zcrypt: Explicitly use a card variable in _zcrypt_send_cprb
  s390/zcrypt: Rework MKVP fields and handling
  s390/zcrypt: Make apfs a real unsigned int field
  s390/zcrypt: Rework domain processing within zcrypt device driver
  s390/zcrypt: Move inline function rng_type6cprb_msgx from header to code
  s390/percpu: Provide arch_raw_cpu_ptr()
  s390: Enable page table check for debug_defconfig
  s390/pgtable: Add s390 support for page table check
  s390/pgtable: Use set_pmd_bit() to invalidate PMD entry
  mm/page_table_check: Pass mm_struct to pxx_user_accessible_page()
  s390/boot: Respect kaslr_enabled() for identity randomization
  s390/Kconfig: Make modules sanity test a module-only option
  s390/setup: Drop stale ident_map_size declaration