Commit Graph

46621 Commits

Author SHA1 Message Date
Oscar Salvador
7bc131c568 arch/x86: do not explicitly clear Reserved flag in free_pagetable
In free_pagetable() we use the non-atomic version for clearing the
PageReserved bit from the page.  free_pagetable() will either call
free_reserved_page() or put_page_bootmem(), which will eventually end up
calling free_reserved_page(), and in there we already clear the
PageReserved flag.

Link: https://lkml.kernel.org/r/20240527044523.29207-1-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:02 -07:00
Peter Xu
d39b6af218 mm: drop leftover comment references to pxx_huge()
pxx_huge() has been removed in recent commit 9636f055da ("mm/treewide:
remove pXd_huge()"), however there are still three comments referencing
the API that got overlooked.  Remove them.

Link: https://lkml.kernel.org/r/20240527154855.528816-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reported-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:02 -07:00
Eric Chanudet
188f87f264 mm/mm_init: use node's number of cpus in deferred_page_init_max_threads
x86_64 is already using the node's cpu as maximum threads.  Make that the
default for all archs setting DEFERRED_STRUCT_PAGE_INIT.

This returns to the behavior prior making the function arch-specific with
commit ecd0965069 ("mm: make deferred init's max threads
arch-specific").

Setting DEFERRED_STRUCT_PAGE_INIT and testing on a few arm64 platforms
shows faster deferred_init_memmap completions:

|         | x13s        | SA8775p-ride | Ampere R137-P31 | Ampere HR330 |
|         | Metal, 32GB | VM, 36GB     | VM, 58GB        | Metal, 128GB |
|         | 8cpus       | 8cpus        | 8cpus           | 32cpus       |
|---------|-------------|--------------|-----------------|--------------|
| threads |  ms     (%) | ms       (%) |  ms         (%) |  ms      (%) |
|---------|-------------|--------------|-----------------|--------------|
| 1       | 108    (0%) | 72      (0%) | 224        (0%) | 324     (0%) |
| cpus    |  24  (-77%) | 36    (-50%) |  40      (-82%) |  56   (-82%) |

Michael Ellerman reported:

: On a machine here (1TB, 40 cores, 4KB pages) the existing code gives:
: 
:   [    0.500124] node 2 deferred pages initialised in 210ms
:   [    0.515790] node 3 deferred pages initialised in 230ms
:   [    0.516061] node 0 deferred pages initialised in 230ms
:   [    0.516522] node 7 deferred pages initialised in 230ms
:   [    0.516672] node 4 deferred pages initialised in 230ms
:   [    0.516798] node 6 deferred pages initialised in 230ms
:   [    0.517051] node 5 deferred pages initialised in 230ms
:   [    0.523887] node 1 deferred pages initialised in 240ms
: 
: vs with the patch:
: 
:   [    0.379613] node 0 deferred pages initialised in 90ms
:   [    0.380388] node 1 deferred pages initialised in 90ms
:   [    0.380540] node 4 deferred pages initialised in 100ms
:   [    0.390239] node 6 deferred pages initialised in 100ms
:   [    0.390249] node 2 deferred pages initialised in 100ms
:   [    0.390786] node 3 deferred pages initialised in 110ms
:   [    0.396721] node 5 deferred pages initialised in 110ms
:   [    0.397095] node 7 deferred pages initialised in 110ms
: 
: Which is a nice speedup.

[echanude@redhat.com: v3]
  Link: https://lkml.kernel.org/r/20240528185455.643227-4-echanude@redhat.com
Link: https://lkml.kernel.org/r/20240522203758.626932-4-echanude@redhat.com
Signed-off-by: Eric Chanudet <echanude@redhat.com>
Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Reviewed-by: Baoquan He <bhe@redhat.com>
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:58 -07:00
Linus Torvalds
769327258a x86-32: fix cmpxchg8b_emu build error with clang
The kernel test robot reported that clang no longer compiles the 32-bit
x86 kernel in some configurations due to commit 95ece48165
("locking/atomic/x86: Rewrite x86_32 arch_atomic64_{,fetch}_{and,or,xor}()
functions").

The build fails with

  arch/x86/include/asm/cmpxchg_32.h:149:9: error: inline assembly requires more registers than available

and the reason seems to be that not only does the cmpxchg8b instruction
need four fixed registers (EDX:EAX and ECX:EBX), with the emulation
fallback the inline asm also wants a fifth fixed register for the
address (it uses %esi for that, but that's just a software convention
with cmpxchg8b_emu).

Avoiding using another pointer input to the asm (and just forcing it to
use the "0(%esi)" addressing that we end up requiring for the sw
fallback) seems to fix the issue.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202406230912.F6XFIyA6-lkp@intel.com/
Fixes: 95ece48165 ("locking/atomic/x86: Rewrite x86_32 arch_atomic64_{,fetch}_{and,or,xor}() functions")
Link: https://lore.kernel.org/all/202406230912.F6XFIyA6-lkp@intel.com/
Suggested-by: Uros Bizjak <ubizjak@gmail.com>
Reviewed-and-Tested-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-06-30 09:21:29 -07:00
Linus Torvalds
b75f947270 hardening fixes for v6.10-rc6
- Remove invalid tty __counted_by annotation (Nathan Chancellor)
 
 - Add missing MODULE_DESCRIPTION()s for KUnit string tests (Jeff Johnson)
 
 - Remove non-functional per-arch kstack entropy filtering
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Merge tag 'hardening-v6.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull hardening fixes from Kees Cook:

 - Remove invalid tty __counted_by annotation (Nathan Chancellor)

 - Add missing MODULE_DESCRIPTION()s for KUnit string tests (Jeff
   Johnson)

 - Remove non-functional per-arch kstack entropy filtering

* tag 'hardening-v6.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  tty: mxser: Remove __counted_by from mxser_board.ports[]
  randomize_kstack: Remove non-functional per-arch entropy filtering
  string: kunit: add missing MODULE_DESCRIPTION() macros
2024-06-28 16:11:02 -07:00
Linus Torvalds
093d9603b6 x86: stop playing stack games in profile_pc()
The 'profile_pc()' function is used for timer-based profiling, which
isn't really all that relevant any more to begin with, but it also ends
up making assumptions based on the stack layout that aren't necessarily
valid.

Basically, the code tries to account the time spent in spinlocks to the
caller rather than the spinlock, and while I support that as a concept,
it's not worth the code complexity or the KASAN warnings when no serious
profiling is done using timers anyway these days.

And the code really does depend on stack layout that is only true in the
simplest of cases.  We've lost the comment at some point (I think when
the 32-bit and 64-bit code was unified), but it used to say:

	Assume the lock function has either no stack frame or a copy
	of eflags from PUSHF.

which explains why it just blindly loads a word or two straight off the
stack pointer and then takes a minimal look at the values to just check
if they might be eflags or the return pc:

	Eflags always has bits 22 and up cleared unlike kernel addresses

but that basic stack layout assumption assumes that there isn't any lock
debugging etc going on that would complicate the code and cause a stack
frame.

It causes KASAN unhappiness reported for years by syzkaller [1] and
others [2].

With no real practical reason for this any more, just remove the code.

Just for historical interest, here's some background commits relating to
this code from 2006:

  0cb91a2293 ("i386: Account spinlocks to the caller during profiling for !FP kernels")
  31679f38d8 ("Simplify profile_pc on x86-64")

and a code unification from 2009:

  ef4512882d ("x86: time_32/64.c unify profile_pc")

but the basics of this thing actually goes back to before the git tree.

Link: https://syzkaller.appspot.com/bug?extid=84fe685c02cd112a2ac3 [1]
Link: https://lore.kernel.org/all/CAK55_s7Xyq=nh97=K=G1sxueOFrJDAvPOJAL4TPTCAYvmxO9_A@mail.gmail.com/ [2]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-06-28 14:27:22 -07:00
Kees Cook
6db1208bf9 randomize_kstack: Remove non-functional per-arch entropy filtering
An unintended consequence of commit 9c573cd313 ("randomize_kstack:
Improve entropy diffusion") was that the per-architecture entropy size
filtering reduced how many bits were being added to the mix, rather than
how many bits were being used during the offsetting. All architectures
fell back to the existing default of 0x3FF (10 bits), which will consume
at most 1KiB of stack space. It seems that this is working just fine,
so let's avoid the confusion and update everything to use the default.

The prior intent of the per-architecture limits were:

  arm64: capped at 0x1FF (9 bits), 5 bits effective
  powerpc: uncapped (10 bits), 6 or 7 bits effective
  riscv: uncapped (10 bits), 6 bits effective
  x86: capped at 0xFF (8 bits), 5 (x86_64) or 6 (ia32) bits effective
  s390: capped at 0xFF (8 bits), undocumented effective entropy

Current discussion has led to just dropping the original per-architecture
filters. The additional entropy appears to be safe for arm64, x86,
and s390. Quoting Arnd, "There is no point pretending that 15.75KB is
somehow safe to use while 15.00KB is not."

Co-developed-by: Yuntao Liu <liuyuntao12@huawei.com>
Signed-off-by: Yuntao Liu <liuyuntao12@huawei.com>
Fixes: 9c573cd313 ("randomize_kstack: Improve entropy diffusion")
Link: https://lore.kernel.org/r/20240617133721.377540-1-liuyuntao12@huawei.com
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # s390
Link: https://lore.kernel.org/r/20240619214711.work.953-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
2024-06-28 08:54:56 -07:00
Arnd Bergmann
d3882564a7 syscalls: fix compat_sys_io_pgetevents_time64 usage
Using sys_io_pgetevents() as the entry point for compat mode tasks
works almost correctly, but misses the sign extension for the min_nr
and nr arguments.

This was addressed on parisc by switching to
compat_sys_io_pgetevents_time64() in commit 6431e92fc8 ("parisc:
io_pgetevents_time64() needs compat syscall in 32-bit compat mode"),
as well as by using more sophisticated system call wrappers on x86 and
s390. However, arm64, mips, powerpc, sparc and riscv still have the
same bug.

Change all of them over to use compat_sys_io_pgetevents_time64()
like parisc already does. This was clearly the intention when the
function was originally added, but it got hooked up incorrectly in
the tables.

Cc: stable@vger.kernel.org
Fixes: 48166e6ea4 ("y2038: add 64-bit time_t syscalls to all 32-bit architectures")
Acked-by: Heiko Carstens <hca@linux.ibm.com> # s390
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2024-06-25 15:57:20 +02:00
Linus Torvalds
b9e6612d61 - An ARM-relevant fix to not free default RMIDs of a resource control group
- A randconfig build fix for the VMware virtual GPU driver
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Merge tag 'x86_urgent_for_v6.10_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Borislav Petkov:

 - An ARM-relevant fix to not free default RMIDs of a resource control
   group

 - A randconfig build fix for the VMware virtual GPU driver

* tag 'x86_urgent_for_v6.10_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/resctrl: Don't try to free nonexistent RMIDs
  drm/vmwgfx: Fix missing HYPERVISOR_GUEST dependency
2024-06-23 07:16:13 -07:00
Linus Torvalds
fe37fe2a5e ARM:
* Fix dangling references to a redistributor region if the vgic was
   prematurely destroyed.
 
 * Properly mark FFA buffers as released, ensuring that both parties
   can make forward progress.
 
 x86:
 
 * Allow getting/setting MSRs for SEV-ES guests, if they're using the pre-6.9
   KVM_SEV_ES_INIT API.
 
 * Always sync pending posted interrupts to the IRR prior to IOAPIC
   route updates, so that EOIs are intercepted properly if the old routing
   table requested that.
 
 Generic:
 
 * Avoid __fls(0)
 
 * Fix reference leak on hwpoisoned page
 
 * Fix a race in kvm_vcpu_on_spin() by ensuring loads and stores are atomic.
 
 * Fix bug in __kvm_handle_hva_range() where KVM calls a function pointer
   that was intended to be a marker only (nothing bad happens but kind of
   a mine and also technically undefined behavior)
 
 * Do not bother accounting allocations that are small and freed before
   getting back to userspace.
 
 Selftests:
 
 * Fix compilation for RISC-V.
 
 * Fix a "shift too big" goof in the KVM_SEV_INIT2 selftest.
 
 * Compute the max mappable gfn for KVM selftests on x86 using GuestMaxPhyAddr
   from KVM's supported CPUID (if it's available).
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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:

   - Fix dangling references to a redistributor region if the vgic was
     prematurely destroyed.

   - Properly mark FFA buffers as released, ensuring that both parties
     can make forward progress.

  x86:

   - Allow getting/setting MSRs for SEV-ES guests, if they're using the
     pre-6.9 KVM_SEV_ES_INIT API.

   - Always sync pending posted interrupts to the IRR prior to IOAPIC
     route updates, so that EOIs are intercepted properly if the old
     routing table requested that.

  Generic:

   - Avoid __fls(0)

   - Fix reference leak on hwpoisoned page

   - Fix a race in kvm_vcpu_on_spin() by ensuring loads and stores are
     atomic.

   - Fix bug in __kvm_handle_hva_range() where KVM calls a function
     pointer that was intended to be a marker only (nothing bad happens
     but kind of a mine and also technically undefined behavior)

   - Do not bother accounting allocations that are small and freed
     before getting back to userspace.

  Selftests:

   - Fix compilation for RISC-V.

   - Fix a "shift too big" goof in the KVM_SEV_INIT2 selftest.

   - Compute the max mappable gfn for KVM selftests on x86 using
     GuestMaxPhyAddr from KVM's supported CPUID (if it's available)"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: SEV-ES: Fix svm_get_msr()/svm_set_msr() for KVM_SEV_ES_INIT guests
  KVM: Discard zero mask with function kvm_dirty_ring_reset
  virt: guest_memfd: fix reference leak on hwpoisoned page
  kvm: do not account temporary allocations to kmem
  MAINTAINERS: Drop Wanpeng Li as a Reviewer for KVM Paravirt support
  KVM: x86: Always sync PIR to IRR prior to scanning I/O APIC routes
  KVM: Stop processing *all* memslots when "null" mmu_notifier handler is found
  KVM: arm64: FFA: Release hyp rx buffer
  KVM: selftests: Fix RISC-V compilation
  KVM: arm64: Disassociate vcpus from redistributor region on teardown
  KVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin()
  KVM: selftests: x86: Prioritize getting max_gfn from GuestPhysBits
  KVM: selftests: Fix shift of 32 bit unsigned int more than 32 bits
2024-06-22 07:41:57 -07:00
Michael Roth
cf6d9d2d24 KVM: SEV-ES: Fix svm_get_msr()/svm_set_msr() for KVM_SEV_ES_INIT guests
With commit 27bd5fdc24 ("KVM: SEV-ES: Prevent MSR access post VMSA
encryption"), older VMMs like QEMU 9.0 and older will fail when booting
SEV-ES guests with something like the following error:

  qemu-system-x86_64: error: failed to get MSR 0x174
  qemu-system-x86_64: ../qemu.git/target/i386/kvm/kvm.c:3950: kvm_get_msrs: Assertion `ret == cpu->kvm_msr_buf->nmsrs' failed.

This is because older VMMs that might still call
svm_get_msr()/svm_set_msr() for SEV-ES guests after guest boot even if
those interfaces were essentially just noops because of the vCPU state
being encrypted and stored separately in the VMSA. Now those VMMs will
get an -EINVAL and generally crash.

Newer VMMs that are aware of KVM_SEV_INIT2 however are already aware of
the stricter limitations of what vCPU state can be sync'd during
guest run-time, so newer QEMU for instance will work both for legacy
KVM_SEV_ES_INIT interface as well as KVM_SEV_INIT2.

So when using KVM_SEV_INIT2 it's okay to assume userspace can deal with
-EINVAL, whereas for legacy KVM_SEV_ES_INIT the kernel might be dealing
with either an older VMM and so it needs to assume that returning
-EINVAL might break the VMM.

Address this by only returning -EINVAL if the guest was started with
KVM_SEV_INIT2. Otherwise, just silently return.

Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Nikunj A Dadhania <nikunj@amd.com>
Reported-by: Srikanth Aithal <sraithal@amd.com>
Closes: https://lore.kernel.org/lkml/37usuu4yu4ok7be2hqexhmcyopluuiqj3k266z4gajc2rcj4yo@eujb23qc3zcm/
Fixes: 27bd5fdc24 ("KVM: SEV-ES: Prevent MSR access post VMSA encryption")
Signed-off-by: Michael Roth <michael.roth@amd.com>
Message-ID: <20240604233510.764949-1-michael.roth@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-21 07:11:29 -04:00
Sean Christopherson
f3ced000a2 KVM: x86: Always sync PIR to IRR prior to scanning I/O APIC routes
Sync pending posted interrupts to the IRR prior to re-scanning I/O APIC
routes, irrespective of whether the I/O APIC is emulated by userspace or
by KVM.  If a level-triggered interrupt routed through the I/O APIC is
pending or in-service for a vCPU, KVM needs to intercept EOIs on said
vCPU even if the vCPU isn't the destination for the new routing, e.g. if
servicing an interrupt using the old routing races with I/O APIC
reconfiguration.

Commit fceb3a36c2 ("KVM: x86: ioapic: Fix level-triggered EOI and
userspace I/OAPIC reconfigure race") fixed the common cases, but
kvm_apic_pending_eoi() only checks if an interrupt is in the local
APIC's IRR or ISR, i.e. misses the uncommon case where an interrupt is
pending in the PIR.

Failure to intercept EOI can manifest as guest hangs with Windows 11 if
the guest uses the RTC as its timekeeping source, e.g. if the VMM doesn't
expose a more modern form of time to the guest.

Cc: stable@vger.kernel.org
Cc: Adamos Ttofari <attofari@amazon.de>
Cc: Raghavendra Rao Ananta <rananta@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20240611014845.82795-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-20 14:18:02 -04:00
Dave Martin
739c976579 x86/resctrl: Don't try to free nonexistent RMIDs
Commit

  6791e0ea30 ("x86/resctrl: Access per-rmid structures by index")

adds logic to map individual monitoring groups into a global index space used
for tracking allocated RMIDs.

Attempts to free the default RMID are ignored in free_rmid(), and this works
fine on x86.

With arm64 MPAM, there is a latent bug here however: on platforms with no
monitors exposed through resctrl, each control group still gets a different
monitoring group ID as seen by the hardware, since the CLOSID always forms part
of the monitoring group ID.

This means that when removing a control group, the code may try to free this
group's default monitoring group RMID for real.  If there are no monitors
however, the RMID tracking table rmid_ptrs[] would be a waste of memory and is
never allocated, leading to a splat when free_rmid() tries to dereference the
table.

One option would be to treat RMID 0 as special for every CLOSID, but this would
be ugly since bookkeeping still needs to be done for these monitoring group IDs
when there are monitors present in the hardware.

Instead, add a gating check of resctrl_arch_mon_capable() in free_rmid(), and
just do nothing if the hardware doesn't have monitors.

This fix mirrors the gating checks already present in
mkdir_rdt_prepare_rmid_alloc() and elsewhere.

No functional change on x86.

  [ bp: Massage commit message. ]

Fixes: 6791e0ea30 ("x86/resctrl: Access per-rmid structures by index")
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/r/20240618140152.83154-1-Dave.Martin@arm.com
2024-06-19 11:39:09 +02:00
Linus Torvalds
46d1907d1c EFI fixes for v6.10 #3
- Ensure that EFI runtime services are not unmapped by PAN on ARM
 - Avoid freeing the memory holding the EFI memory map inadvertently on
   x86
 - Avoid a false positive kmemleak warning on arm64
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Merge tag 'efi-fixes-for-v6.10-3' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi

Pull EFI fixes from Ard Biesheuvel:
 "Another small set of EFI fixes. Only the x86 one is likely to affect
  any actual users (and has a cc:stable), but the issue it fixes was
  only observed in an unusual context (kexec in a confidential VM).

   - Ensure that EFI runtime services are not unmapped by PAN on ARM

   - Avoid freeing the memory holding the EFI memory map inadvertently
     on x86

   - Avoid a false positive kmemleak warning on arm64"

* tag 'efi-fixes-for-v6.10-3' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
  efi/arm64: Fix kmemleak false positive in arm64_efi_rt_init()
  efi/x86: Free EFI memory map only when installing a new one.
  efi/arm: Disable LPAE PAN when calling EFI runtime services
2024-06-18 07:48:56 -07:00
Linus Torvalds
08a6b55aa0 Misc fixes:
- Fix the 8 bytes get_user() logic on x86-32
 
  - Fix build bug that creates weird & mistaken target directory under arch/x86/
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-urgent-2024-06-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Ingo Molnar:

 - Fix the 8 bytes get_user() logic on x86-32

 - Fix build bug that creates weird & mistaken target directory under
   arch/x86/

* tag 'x86-urgent-2024-06-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/boot: Don't add the EFI stub to targets, again
  x86/uaccess: Fix missed zeroing of ia32 u64 get_user() range checking
2024-06-15 11:03:05 -07:00
Ard Biesheuvel
75dde792d6 efi/x86: Free EFI memory map only when installing a new one.
The logic in __efi_memmap_init() is shared between two different
execution flows:
- mapping the EFI memory map early or late into the kernel VA space, so
  that its entries can be accessed;
- the x86 specific cloning of the EFI memory map in order to insert new
  entries that are created as a result of making a memory reservation
  via a call to efi_mem_reserve().

In the former case, the underlying memory containing the kernel's view
of the EFI memory map (which may be heavily modified by the kernel
itself on x86) is not modified at all, and the only thing that changes
is the virtual mapping of this memory, which is different between early
and late boot.

In the latter case, an entirely new allocation is created that carries a
new, updated version of the kernel's view of the EFI memory map. When
installing this new version, the old version will no longer be
referenced, and if the memory was allocated by the kernel, it will leak
unless it gets freed.

The logic that implements this freeing currently lives on the code path
that is shared between these two use cases, but it should only apply to
the latter. So move it to the correct spot.

While at it, drop the dummy definition for non-x86 architectures, as
that is no longer needed.

Cc: <stable@vger.kernel.org>
Fixes: f0ef652347 ("efi: Fix efi_memmap_alloc() leaks")
Tested-by: Ashish Kalra <Ashish.Kalra@amd.com>
Link: https://lore.kernel.org/all/36ad5079-4326-45ed-85f6-928ff76483d3@amd.com
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2024-06-15 10:25:02 +02:00
Linus Torvalds
3572597ca8 memblock: fix validation of NUMA coverage
To check for unset node ID for a range memblock_validate_numa_coverage()
 was checking for NUMA_NO_NODE, but x86 used MAX_NUMNODES when no node ID
 was specified by buggy firmware.
 
 Update memblock to substitute MAX_NUMNODES with NUMA_NO_NODE in
 memblock_set_node() and use NUMA_NO_NODE in x86::numa_init().
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Merge tag 'fixes-2024-06-13' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock

Pull memblock fixes from Mike Rapoport:
 "Fix validation of NUMA coverage.

  memblock_validate_numa_coverage() was checking for a unset node ID
  using NUMA_NO_NODE, but x86 used MAX_NUMNODES when no node ID was
  specified by buggy firmware.

  Update memblock to substitute MAX_NUMNODES with NUMA_NO_NODE in
  memblock_set_node() and use NUMA_NO_NODE in x86::numa_init()"

* tag 'fixes-2024-06-13' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
  x86/mm/numa: Use NUMA_NO_NODE when calling memblock_set_node()
  memblock: make memblock_set_node() also warn about use of MAX_NUMNODES
2024-06-13 10:09:29 -07:00
Benjamin Segall
b2747f108b x86/boot: Don't add the EFI stub to targets, again
This is a re-commit of

  da05b143a3 ("x86/boot: Don't add the EFI stub to targets")

after the tagged patch incorrectly reverted it.

vmlinux-objs-y is added to targets, with an assumption that they are all
relative to $(obj); adding a $(objtree)/drivers/...  path causes the
build to incorrectly create a useless
arch/x86/boot/compressed/drivers/...  directory tree.

Fix this just by using a different make variable for the EFI stub.

Fixes: cb8bda8ad4 ("x86/boot/compressed: Rename efi_thunk_64.S to efi-mixed.S")
Signed-off-by: Ben Segall <bsegall@google.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: stable@vger.kernel.org # v6.1+
Link: https://lore.kernel.org/r/xm267ceukksz.fsf@bsegall.svl.corp.google.com
2024-06-13 10:32:36 +02:00
Kees Cook
8c860ed825 x86/uaccess: Fix missed zeroing of ia32 u64 get_user() range checking
When reworking the range checking for get_user(), the get_user_8() case
on 32-bit wasn't zeroing the high register. (The jump to bad_get_user_8
was accidentally dropped.) Restore the correct error handling
destination (and rename the jump to using the expected ".L" prefix).

While here, switch to using a named argument ("size") for the call
template ("%c4" to "%c[size]") as already used in the other call
templates in this file.

Found after moving the usercopy selftests to KUnit:

      # usercopy_test_invalid: EXPECTATION FAILED at
      lib/usercopy_kunit.c:278
      Expected val_u64 == 0, but
          val_u64 == -60129542144 (0xfffffff200000000)

Closes: https://lore.kernel.org/all/CABVgOSn=tb=Lj9SxHuT4_9MTjjKVxsq-ikdXC4kGHO4CfKVmGQ@mail.gmail.com
Fixes: b19b74bc99 ("x86/mm: Rework address range check in get_user() and put_user()")
Reported-by: David Gow <davidgow@google.com>
Signed-off-by: Kees Cook <kees@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Tested-by: David Gow <davidgow@google.com>
Link: https://lore.kernel.org/all/20240610210213.work.143-kees%40kernel.org
2024-06-11 16:08:43 -07:00
Linus Torvalds
7cedb020d5 Miscellaneous fixes:
- Fix kexec() crash if call depth tracking is enabled
 
  - Fix SMN reads on inaccessible registers on certain AMD systems
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-urgent-2024-06-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Ingo Molnar:
 "Miscellaneous fixes:

   - Fix kexec() crash if call depth tracking is enabled

   - Fix SMN reads on inaccessible registers on certain AMD systems"

* tag 'x86-urgent-2024-06-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/amd_nb: Check for invalid SMN reads
  x86/kexec: Fix bug with call depth tracking
2024-06-08 09:36:08 -07:00
Jan Beulich
3ac36aa730 x86/mm/numa: Use NUMA_NO_NODE when calling memblock_set_node()
memblock_set_node() warns about using MAX_NUMNODES, see

  e0eec24e2e ("memblock: make memblock_set_node() also warn about use of MAX_NUMNODES")

for details.

Reported-by: Narasimhan V <Narasimhan.V@amd.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: stable@vger.kernel.org
[bp: commit message]
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20240603141005.23261-1-bp@kernel.org
Link: https://lore.kernel.org/r/abadb736-a239-49e4-ab42-ace7acdd4278@suse.com
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
2024-06-06 22:20:39 +03:00
Yazen Ghannam
c625dabbf1 x86/amd_nb: Check for invalid SMN reads
AMD Zen-based systems use a System Management Network (SMN) that
provides access to implementation-specific registers.

SMN accesses are done indirectly through an index/data pair in PCI
config space. The PCI config access may fail and return an error code.
This would prevent the "read" value from being updated.

However, the PCI config access may succeed, but the return value may be
invalid. This is in similar fashion to PCI bad reads, i.e. return all
bits set.

Most systems will return 0 for SMN addresses that are not accessible.
This is in line with AMD convention that unavailable registers are
Read-as-Zero/Writes-Ignored.

However, some systems will return a "PCI Error Response" instead. This
value, along with an error code of 0 from the PCI config access, will
confuse callers of the amd_smn_read() function.

Check for this condition, clear the return value, and set a proper error
code.

Fixes: ddfe43cdc0 ("x86/amd_nb: Add SMN and Indirect Data Fabric access for AMD Fam17h")
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230403164244.471141-1-yazen.ghannam@amd.com
2024-06-05 21:23:34 +02:00
Tao Su
db574f2f96 KVM: x86/mmu: Don't save mmu_invalidate_seq after checking private attr
Drop the second snapshot of mmu_invalidate_seq in kvm_faultin_pfn().
Before checking the mismatch of private vs. shared, mmu_invalidate_seq is
saved to fault->mmu_seq, which can be used to detect an invalidation
related to the gfn occurred, i.e. KVM will not install a mapping in page
table if fault->mmu_seq != mmu_invalidate_seq.

Currently there is a second snapshot of mmu_invalidate_seq, which may not
be same as the first snapshot in kvm_faultin_pfn(), i.e. the gfn attribute
may be changed between the two snapshots, but the gfn may be mapped in
page table without hindrance. Therefore, drop the second snapshot as it
has no obvious benefits.

Fixes: f6adeae81f ("KVM: x86/mmu: Handle no-slot faults at the beginning of kvm_faultin_pfn()")
Signed-off-by: Tao Su <tao1.su@linux.intel.com>
Message-ID: <20240528102234.2162763-1-tao1.su@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-05 06:45:06 -04:00
Paolo Bonzini
b3233c737e Merge branch 'kvm-fixes-6.10-1' into HEAD
* Fixes and debugging help for the #VE sanity check.  Also disable
  it by default, even for CONFIG_DEBUG_KERNEL, because it was found
  to trigger spuriously (most likely a processor erratum as the
  exact symptoms vary by generation).

* Avoid WARN() when two NMIs arrive simultaneously during an NMI-disabled
  situation (GIF=0 or interrupt shadow) when the processor supports
  virtual NMI.  While generally KVM will not request an NMI window
  when virtual NMIs are supported, in this case it *does* have to
  single-step over the interrupt shadow or enable the STGI intercept,
  in order to deliver the latched second NMI.

* Drop support for hand tuning APIC timer advancement from userspace.
  Since we have adaptive tuning, and it has proved to work well,
  drop the module parameter for manual configuration and with it a
  few stupid bugs that it had.
2024-06-03 13:18:08 -04:00
Sean Christopherson
89a58812c4 KVM: x86: Drop support for hand tuning APIC timer advancement from userspace
Remove support for specifying a static local APIC timer advancement value,
and instead present a read-only boolean parameter to let userspace enable
or disable KVM's dynamic APIC timer advancement.  Realistically, it's all
but impossible for userspace to specify an advancement that is more
precise than what KVM's adaptive tuning can provide.  E.g. a static value
needs to be tuned for the exact hardware and kernel, and if KVM is using
hrtimers, likely requires additional tuning for the exact configuration of
the entire system.

Dropping support for a userspace provided value also fixes several flaws
in the interface.  E.g. KVM interprets a negative value other than -1 as a
large advancement, toggling between a negative and positive value yields
unpredictable behavior as vCPUs will switch from dynamic to static
advancement, changing the advancement in the middle of VM creation can
result in different values for vCPUs within a VM, etc.  Those flaws are
mostly fixable, but there's almost no justification for taking on yet more
complexity (it's minimal complexity, but still non-zero).

The only arguments against using KVM's adaptive tuning is if a setup needs
a higher maximum, or if the adjustments are too reactive, but those are
arguments for letting userspace control the absolute max advancement and
the granularity of each adjustment, e.g. similar to how KVM provides knobs
for halt polling.

Link: https://lore.kernel.org/all/20240520115334.852510-1-zhoushuling@huawei.com
Cc: Shuling Zhou <zhoushuling@huawei.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20240522010304.1650603-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-03 13:08:05 -04:00
Ravi Bangoria
b7e4be0a22 KVM: SEV-ES: Delegate LBR virtualization to the processor
As documented in APM[1], LBR Virtualization must be enabled for SEV-ES
guests. Although KVM currently enforces LBRV for SEV-ES guests, there
are multiple issues with it:

o MSR_IA32_DEBUGCTLMSR is still intercepted. Since MSR_IA32_DEBUGCTLMSR
  interception is used to dynamically toggle LBRV for performance reasons,
  this can be fatal for SEV-ES guests. For ex SEV-ES guest on Zen3:

  [guest ~]# wrmsr 0x1d9 0x4
  KVM: entry failed, hardware error 0xffffffff
  EAX=00000004 EBX=00000000 ECX=000001d9 EDX=00000000

  Fix this by never intercepting MSR_IA32_DEBUGCTLMSR for SEV-ES guests.
  No additional save/restore logic is required since MSR_IA32_DEBUGCTLMSR
  is of swap type A.

o KVM will disable LBRV if userspace sets MSR_IA32_DEBUGCTLMSR before the
  VMSA is encrypted. Fix this by moving LBRV enablement code post VMSA
  encryption.

[1]: AMD64 Architecture Programmer's Manual Pub. 40332, Rev. 4.07 - June
     2023, Vol 2, 15.35.2 Enabling SEV-ES.
     https://bugzilla.kernel.org/attachment.cgi?id=304653

Fixes: 376c6d2850 ("KVM: SVM: Provide support for SEV-ES vCPU creation/loading")
Co-developed-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com>
Message-ID: <20240531044644.768-4-ravi.bangoria@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-03 13:07:18 -04:00
Ravi Bangoria
d922056215 KVM: SEV-ES: Disallow SEV-ES guests when X86_FEATURE_LBRV is absent
As documented in APM[1], LBR Virtualization must be enabled for SEV-ES
guests. So, prevent SEV-ES guests when LBRV support is missing.

[1]: AMD64 Architecture Programmer's Manual Pub. 40332, Rev. 4.07 - June
     2023, Vol 2, 15.35.2 Enabling SEV-ES.
     https://bugzilla.kernel.org/attachment.cgi?id=304653

Fixes: 376c6d2850 ("KVM: SVM: Provide support for SEV-ES vCPU creation/loading")
Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com>
Message-ID: <20240531044644.768-3-ravi.bangoria@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-03 13:06:48 -04:00
Nikunj A Dadhania
27bd5fdc24 KVM: SEV-ES: Prevent MSR access post VMSA encryption
KVM currently allows userspace to read/write MSRs even after the VMSA is
encrypted. This can cause unintentional issues if MSR access has side-
effects. For ex, while migrating a guest, userspace could attempt to
migrate MSR_IA32_DEBUGCTLMSR and end up unintentionally disabling LBRV on
the target. Fix this by preventing access to those MSRs which are context
switched via the VMSA, once the VMSA is encrypted.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com>
Message-ID: <20240531044644.768-2-ravi.bangoria@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-03 13:06:48 -04:00
David Kaplan
93c1800b37 x86/kexec: Fix bug with call depth tracking
The call to cc_platform_has() triggers a fault and system crash if call depth
tracking is active because the GS segment has been reset by load_segments() and
GS_BASE is now 0 but call depth tracking uses per-CPU variables to operate.

Call cc_platform_has() earlier in the function when GS is still valid.

  [ bp: Massage. ]

Fixes: 5d8213864a ("x86/retbleed: Add SKL return thunk")
Signed-off-by: David Kaplan <david.kaplan@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/20240603083036.637-1-bp@kernel.org
2024-06-03 17:19:03 +02:00
Linus Torvalds
a693b9c95a Miscellaneous topology parsing fixes:
- Fix topology parsing regression on older CPUs in the
    new AMD/Hygon parser
 
  - Fix boot crash on odd Intel Quark and similar CPUs that
    do not fill out cpuinfo_x86::x86_clflush_size and zero out
    cpuinfo_x86::x86_cache_alignment as a result. Provide
    32 bytes as a general fallback value.
 
  - Fix topology enumeration on certain rare CPUs where the
    BIOS locks certain CPUID leaves and the kernel unlocked
    them late, which broke with the new topology parsing code.
    Factor out this unlocking logic and move it earlier
    in the parsing sequence.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-urgent-2024-06-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Ingo Molnar:
 "Miscellaneous topology parsing fixes:

   - Fix topology parsing regression on older CPUs in the new AMD/Hygon
     parser

   - Fix boot crash on odd Intel Quark and similar CPUs that do not fill
     out cpuinfo_x86::x86_clflush_size and zero out
     cpuinfo_x86::x86_cache_alignment as a result.

     Provide 32 bytes as a general fallback value.

   - Fix topology enumeration on certain rare CPUs where the BIOS locks
     certain CPUID leaves and the kernel unlocked them late, which broke
     with the new topology parsing code. Factor out this unlocking logic
     and move it earlier in the parsing sequence"

* tag 'x86-urgent-2024-06-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/topology/intel: Unlock CPUID before evaluating anything
  x86/cpu: Provide default cache line size if not enumerated
  x86/topology/amd: Evaluate SMT in CPUID leaf 0x8000001e only on family 0x17 and greater
2024-06-02 09:32:34 -07:00
Linus Torvalds
3fca58ffad Export a symbol to make life easier for instrumentation/debugging.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-urgent-2024-06-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fix from Ingo Molnar:
 "Export a symbol to make life easier for instrumentation/debugging"

* tag 'sched-urgent-2024-06-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/x86: Export 'percpu arch_freq_scale'
2024-06-02 09:23:35 -07:00
Thomas Gleixner
0c2f6d0461 x86/topology/intel: Unlock CPUID before evaluating anything
Intel CPUs have a MSR bit to limit CPUID enumeration to leaf two. If
this bit is set by the BIOS then CPUID evaluation including topology
enumeration does not work correctly as the evaluation code does not try
to analyze any leaf greater than two.

This went unnoticed before because the original topology code just
repeated evaluation several times and managed to overwrite the initial
limited information with the correct one later. The new evaluation code
does it once and therefore ends up with the limited and wrong
information.

Cure this by unlocking CPUID right before evaluating anything which
depends on the maximum CPUID leaf being greater than two instead of
rereading stuff after unlock.

Fixes: 22d63660c3 ("x86/cpu: Use common topology code for Intel")
Reported-by: Peter Schneider <pschneider1968@googlemail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Peter Schneider <pschneider1968@googlemail.com>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/fd3f73dc-a86f-4bcf-9c60-43556a21eb42@googlemail.com
2024-05-31 20:25:56 +02:00
Phil Auld
d40605a682 sched/x86: Export 'percpu arch_freq_scale'
Commit:

  7bc263840b ("sched/topology: Consolidate and clean up access to a CPU's max compute capacity")

removed rq->cpu_capacity_orig in favor of using arch_scale_freq_capacity()
calls. Export the underlying percpu symbol on x86 so that external trace
point helper modules can be made to work again.

Signed-off-by: Phil Auld <pauld@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240530181548.2039216-1-pauld@redhat.com
2024-05-31 11:48:42 +02:00
Jeff Johnson
dc8e5dfb52 perf/x86/intel: Add missing MODULE_DESCRIPTION() lines
Fix the 'make W=1 C=1' warnings:

  WARNING: modpost: missing MODULE_DESCRIPTION() in arch/x86/events/intel/intel-uncore.o
  WARNING: modpost: missing MODULE_DESCRIPTION() in arch/x86/events/intel/intel-cstate.o

Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Link: https://lore.kernel.org/r/20240530-md-arch-x86-events-intel-v1-1-8252194ed20a@quicinc.com
2024-05-31 11:41:15 +02:00
Jeff Johnson
0a44078f2b perf/x86/rapl: Add missing MODULE_DESCRIPTION() line
Fix the warning from 'make C=1 W=1':

  WARNING: modpost: missing MODULE_DESCRIPTION() in arch/x86/events/rapl.o

Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Link: https://lore.kernel.org/r/20240530-md-arch-x86-events-v1-1-e45ffa8af99f@quicinc.com
2024-05-31 11:41:04 +02:00
Dave Hansen
2a38e4ca30 x86/cpu: Provide default cache line size if not enumerated
tl;dr: CPUs with CPUID.80000008H but without CPUID.01H:EDX[CLFSH]
will end up reporting cache_line_size()==0 and bad things happen.
Fill in a default on those to avoid the problem.

Long Story:

The kernel dies a horrible death if c->x86_cache_alignment (aka.
cache_line_size() is 0.  Normally, this value is populated from
c->x86_clflush_size.

Right now the code is set up to get c->x86_clflush_size from two
places.  First, modern CPUs get it from CPUID.  Old CPUs that don't
have leaf 0x80000008 (or CPUID at all) just get some sane defaults
from the kernel in get_cpu_address_sizes().

The vast majority of CPUs that have leaf 0x80000008 also get
->x86_clflush_size from CPUID.  But there are oddballs.

Intel Quark CPUs[1] and others[2] have leaf 0x80000008 but don't set
CPUID.01H:EDX[CLFSH], so they skip over filling in ->x86_clflush_size:

	cpuid(0x00000001, &tfms, &misc, &junk, &cap0);
	if (cap0 & (1<<19))
		c->x86_clflush_size = ((misc >> 8) & 0xff) * 8;

So they: land in get_cpu_address_sizes() and see that CPUID has level
0x80000008 and jump into the side of the if() that does not fill in
c->x86_clflush_size.  That assigns a 0 to c->x86_cache_alignment, and
hilarity ensues in code like:

        buffer = kzalloc(ALIGN(sizeof(*buffer), cache_line_size()),
                         GFP_KERNEL);

To fix this, always provide a sane value for ->x86_clflush_size.

Big thanks to Andy Shevchenko for finding and reporting this and also
providing a first pass at a fix. But his fix was only partial and only
worked on the Quark CPUs.  It would not, for instance, have worked on
the QEMU config.

1. https://raw.githubusercontent.com/InstLatx64/InstLatx64/master/GenuineIntel/GenuineIntel0000590_Clanton_03_CPUID.txt
2. You can also get this behavior if you use "-cpu 486,+clzero"
   in QEMU.

[ dhansen: remove 'vp_bits_from_cpuid' reference in changelog
	   because bpetkov brutally murdered it recently. ]

Fixes: fbf6449f84 ("x86/sev-es: Set x86_virt_bits to the correct value straight away, instead of a two-phase approach")
Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Jörn Heusipp <osmanx@heusipp.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20240516173928.3960193-1-andriy.shevchenko@linux.intel.com/
Link: https://lore.kernel.org/lkml/5e31cad3-ad4d-493e-ab07-724cfbfaba44@heusipp.de/
Link: https://lore.kernel.org/all/20240517200534.8EC5F33E%40davehans-spike.ostc.intel.com
2024-05-30 08:29:45 -07:00
Thomas Gleixner
34bf6bae32 x86/topology/amd: Evaluate SMT in CPUID leaf 0x8000001e only on family 0x17 and greater
The new AMD/HYGON topology parser evaluates the SMT information in CPUID leaf
0x8000001e unconditionally while the original code restricted it to CPUs with
family 0x17 and greater.

This breaks family 0x15 CPUs which advertise that leaf and have a non-zero
value in the SMT section. The machine boots, but the scheduler complains loudly
about the mismatch of the core IDs:

  WARNING: CPU: 1 PID: 0 at kernel/sched/core.c:6482 sched_cpu_starting+0x183/0x250
  WARNING: CPU: 0 PID: 1 at kernel/sched/topology.c:2408 build_sched_domains+0x76b/0x12b0

Add the condition back to cure it.

  [ bp: Make it actually build because grandpa is not concerned with
    trivial stuff. :-P ]

Fixes: f7fb3b2dd9 ("x86/cpu: Provide an AMD/HYGON specific topology parser")
Closes: https://gitlab.archlinux.org/archlinux/packaging/packages/linux/-/issues/56
Reported-by: Tim Teichmann <teichmanntim@outlook.de>
Reported-by: Christian Heusel <christian@heusel.eu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Tim Teichmann <teichmanntim@outlook.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/7skhx6mwe4hxiul64v6azhlxnokheorksqsdbp7qw6g2jduf6c@7b5pvomauugk
2024-05-30 15:58:55 +02:00
Linus Torvalds
a0db36ed57 Misc fixes:
- Fix x86 IRQ vector leak caused by a CPU offlining race
 
  - Fix build failure in the riscv-imsic irqchip driver
    caused by an API-change semantic conflict
 
  - Fix use-after-free in irq_find_at_or_after()
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'irq-urgent-2024-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull irq fixes from Ingo Molnar:

 - Fix x86 IRQ vector leak caused by a CPU offlining race

 - Fix build failure in the riscv-imsic irqchip driver
   caused by an API-change semantic conflict

 - Fix use-after-free in irq_find_at_or_after()

* tag 'irq-urgent-2024-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq/irqdesc: Prevent use-after-free in irq_find_at_or_after()
  genirq/cpuhotplug, x86/vector: Prevent vector leak during CPU offline
  irqchip/riscv-imsic: Fixup riscv_ipi_set_virq_range() conflict
2024-05-25 14:48:40 -07:00
Linus Torvalds
3a390f24b7 Miscellaneous fixes:
- Fix regressions of the new x86 CPU VFM (vendor/family/model)
    enumeration/matching code
 
  - Fix crash kernel detection on buggy firmware with
    non-compliant ACPI MADT tables
 
  - Address Kconfig warning
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-urgent-2024-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Ingo Molnar:

 - Fix regressions of the new x86 CPU VFM (vendor/family/model)
   enumeration/matching code

 - Fix crash kernel detection on buggy firmware with
   non-compliant ACPI MADT tables

 - Address Kconfig warning

* tag 'x86-urgent-2024-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/cpu: Fix x86_match_cpu() to match just X86_VENDOR_INTEL
  crypto: x86/aes-xts - switch to new Intel CPU model defines
  x86/topology: Handle bogus ACPI tables correctly
  x86/kconfig: Select ARCH_WANT_FRAME_POINTERS again when UNWINDER_FRAME_POINTER=y
2024-05-25 14:40:09 -07:00
Linus Torvalds
2313022ec5 This pull request contains the following changes for UML:
- Fixes for -Wmissing-prototypes warnings and further cleanup
 - Remove callback returning void from rtc and virtio drivers
 - Fix bash location
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Merge tag 'uml-for-linus-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux

Pull UML updates from Richard Weinberger:

 - Fixes for -Wmissing-prototypes warnings and further cleanup

 - Remove callback returning void from rtc and virtio drivers

 - Fix bash location

* tag 'uml-for-linus-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux: (26 commits)
  um: virtio_uml: Convert to platform remove callback returning void
  um: rtc: Convert to platform remove callback returning void
  um: Remove unused do_get_thread_area function
  um: Fix -Wmissing-prototypes warnings for __vdso_*
  um: Add an internal header shared among the user code
  um: Fix the declaration of kasan_map_memory
  um: Fix the -Wmissing-prototypes warning for get_thread_reg
  um: Fix the -Wmissing-prototypes warning for __switch_mm
  um: Fix -Wmissing-prototypes warnings for (rt_)sigreturn
  um: Stop tracking host PID in cpu_tasks
  um: process: remove unused 'n' variable
  um: vector: remove unused len variable/calculation
  um: vector: fix bpfflash parameter evaluation
  um: slirp: remove set but unused variable 'pid'
  um: signal: move pid variable where needed
  um: Makefile: use bash from the environment
  um: Add winch to winch_handlers before registering winch IRQ
  um: Fix -Wmissing-prototypes warnings for __warp_* and foo
  um: Fix -Wmissing-prototypes warnings for text_poke*
  um: Move declarations to proper headers
  ...
2024-05-25 13:17:48 -07:00
Linus Torvalds
0b32d436c0 Jeff Xu's implementation of the mseal() syscall.
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Merge tag 'mm-stable-2024-05-24-11-49' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull more mm updates from Andrew Morton:
 "Jeff Xu's implementation of the mseal() syscall"

* tag 'mm-stable-2024-05-24-11-49' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  selftest mm/mseal read-only elf memory segment
  mseal: add documentation
  selftest mm/mseal memory sealing
  mseal: add mseal syscall
  mseal: wire up mseal syscall
2024-05-24 12:47:28 -07:00
Linus Torvalds
9351f138d1 xen: branch for v6.10-rc1
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Merge tag 'for-linus-6.10a-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen updates from Juergen Gross:

 - a small cleanup in the drivers/xen/xenbus Makefile

 - a fix of the Xen xenstore driver to improve connecting to a late
   started Xenstore

 - an enhancement for better support of ballooning in PVH guests

 - a cleanup using try_cmpxchg() instead of open coding it

* tag 'for-linus-6.10a-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  drivers/xen: Improve the late XenStore init protocol
  xen/xenbus: Use *-y instead of *-objs in Makefile
  xen/x86: add extra pages to unpopulated-alloc if available
  locking/x86/xen: Use try_cmpxchg() in xen_alloc_p2m_entry()
2024-05-24 10:24:49 -07:00
Jeff Xu
ff388fe5c4 mseal: wire up mseal syscall
Patch series "Introduce mseal", v10.

This patchset proposes a new mseal() syscall for the Linux kernel.

In a nutshell, mseal() protects the VMAs of a given virtual memory range
against modifications, such as changes to their permission bits.

Modern CPUs support memory permissions, such as the read/write (RW) and
no-execute (NX) bits.  Linux has supported NX since the release of kernel
version 2.6.8 in August 2004 [1].  The memory permission feature improves
the security stance on memory corruption bugs, as an attacker cannot
simply write to arbitrary memory and point the code to it.  The memory
must be marked with the X bit, or else an exception will occur. 
Internally, the kernel maintains the memory permissions in a data
structure called VMA (vm_area_struct).  mseal() additionally protects the
VMA itself against modifications of the selected seal type.

Memory sealing is useful to mitigate memory corruption issues where a
corrupted pointer is passed to a memory management system.  For example,
such an attacker primitive can break control-flow integrity guarantees
since read-only memory that is supposed to be trusted can become writable
or .text pages can get remapped.  Memory sealing can automatically be
applied by the runtime loader to seal .text and .rodata pages and
applications can additionally seal security critical data at runtime.  A
similar feature already exists in the XNU kernel with the
VM_FLAGS_PERMANENT [3] flag and on OpenBSD with the mimmutable syscall
[4].  Also, Chrome wants to adopt this feature for their CFI work [2] and
this patchset has been designed to be compatible with the Chrome use case.

Two system calls are involved in sealing the map:  mmap() and mseal().

The new mseal() is an syscall on 64 bit CPU, and with following signature:

int mseal(void addr, size_t len, unsigned long flags)
addr/len: memory range.
flags: reserved.

mseal() blocks following operations for the given memory range.

1> Unmapping, moving to another location, and shrinking the size,
   via munmap() and mremap(), can leave an empty space, therefore can
   be replaced with a VMA with a new set of attributes.

2> Moving or expanding a different VMA into the current location,
   via mremap().

3> Modifying a VMA via mmap(MAP_FIXED).

4> Size expansion, via mremap(), does not appear to pose any specific
   risks to sealed VMAs. It is included anyway because the use case is
   unclear. In any case, users can rely on merging to expand a sealed VMA.

5> mprotect() and pkey_mprotect().

6> Some destructive madvice() behaviors (e.g. MADV_DONTNEED) for anonymous
   memory, when users don't have write permission to the memory. Those
   behaviors can alter region contents by discarding pages, effectively a
   memset(0) for anonymous memory.

The idea that inspired this patch comes from Stephen Röttger’s work in
V8 CFI [5].  Chrome browser in ChromeOS will be the first user of this
API.

Indeed, the Chrome browser has very specific requirements for sealing,
which are distinct from those of most applications.  For example, in the
case of libc, sealing is only applied to read-only (RO) or read-execute
(RX) memory segments (such as .text and .RELRO) to prevent them from
becoming writable, the lifetime of those mappings are tied to the lifetime
of the process.

Chrome wants to seal two large address space reservations that are managed
by different allocators.  The memory is mapped RW- and RWX respectively
but write access to it is restricted using pkeys (or in the future ARM
permission overlay extensions).  The lifetime of those mappings are not
tied to the lifetime of the process, therefore, while the memory is
sealed, the allocators still need to free or discard the unused memory. 
For example, with madvise(DONTNEED).

However, always allowing madvise(DONTNEED) on this range poses a security
risk.  For example if a jump instruction crosses a page boundary and the
second page gets discarded, it will overwrite the target bytes with zeros
and change the control flow.  Checking write-permission before the discard
operation allows us to control when the operation is valid.  In this case,
the madvise will only succeed if the executing thread has PKEY write
permissions and PKRU changes are protected in software by control-flow
integrity.

Although the initial version of this patch series is targeting the Chrome
browser as its first user, it became evident during upstream discussions
that we would also want to ensure that the patch set eventually is a
complete solution for memory sealing and compatible with other use cases. 
The specific scenario currently in mind is glibc's use case of loading and
sealing ELF executables.  To this end, Stephen is working on a change to
glibc to add sealing support to the dynamic linker, which will seal all
non-writable segments at startup.  Once this work is completed, all
applications will be able to automatically benefit from these new
protections.

In closing, I would like to formally acknowledge the valuable
contributions received during the RFC process, which were instrumental in
shaping this patch:

Jann Horn: raising awareness and providing valuable insights on the
  destructive madvise operations.
Liam R. Howlett: perf optimization.
Linus Torvalds: assisting in defining system call signature and scope.
Theo de Raadt: sharing the experiences and insight gained from
  implementing mimmutable() in OpenBSD.

MM perf benchmarks
==================
This patch adds a loop in the mprotect/munmap/madvise(DONTNEED) to
check the VMAs’ sealing flag, so that no partial update can be made,
when any segment within the given memory range is sealed.

To measure the performance impact of this loop, two tests are developed.
[8]

The first is measuring the time taken for a particular system call,
by using clock_gettime(CLOCK_MONOTONIC). The second is using
PERF_COUNT_HW_REF_CPU_CYCLES (exclude user space). Both tests have
similar results.

The tests have roughly below sequence:
for (i = 0; i < 1000, i++)
    create 1000 mappings (1 page per VMA)
    start the sampling
    for (j = 0; j < 1000, j++)
        mprotect one mapping
    stop and save the sample
    delete 1000 mappings
calculates all samples.

Below tests are performed on Intel(R) Pentium(R) Gold 7505 @ 2.00GHz,
4G memory, Chromebook.

Based on the latest upstream code:
The first test (measuring time)
syscall__	vmas	t	t_mseal	delta_ns	per_vma	%
munmap__  	1	909	944	35	35	104%
munmap__  	2	1398	1502	104	52	107%
munmap__  	4	2444	2594	149	37	106%
munmap__  	8	4029	4323	293	37	107%
munmap__  	16	6647	6935	288	18	104%
munmap__  	32	11811	12398	587	18	105%
mprotect	1	439	465	26	26	106%
mprotect	2	1659	1745	86	43	105%
mprotect	4	3747	3889	142	36	104%
mprotect	8	6755	6969	215	27	103%
mprotect	16	13748	14144	396	25	103%
mprotect	32	27827	28969	1142	36	104%
madvise_	1	240	262	22	22	109%
madvise_	2	366	442	76	38	121%
madvise_	4	623	751	128	32	121%
madvise_	8	1110	1324	215	27	119%
madvise_	16	2127	2451	324	20	115%
madvise_	32	4109	4642	534	17	113%

The second test (measuring cpu cycle)
syscall__	vmas	cpu	cmseal	delta_cpu	per_vma	%
munmap__	1	1790	1890	100	100	106%
munmap__	2	2819	3033	214	107	108%
munmap__	4	4959	5271	312	78	106%
munmap__	8	8262	8745	483	60	106%
munmap__	16	13099	14116	1017	64	108%
munmap__	32	23221	24785	1565	49	107%
mprotect	1	906	967	62	62	107%
mprotect	2	3019	3203	184	92	106%
mprotect	4	6149	6569	420	105	107%
mprotect	8	9978	10524	545	68	105%
mprotect	16	20448	21427	979	61	105%
mprotect	32	40972	42935	1963	61	105%
madvise_	1	434	497	63	63	115%
madvise_	2	752	899	147	74	120%
madvise_	4	1313	1513	200	50	115%
madvise_	8	2271	2627	356	44	116%
madvise_	16	4312	4883	571	36	113%
madvise_	32	8376	9319	943	29	111%

Based on the result, for 6.8 kernel, sealing check adds
20-40 nano seconds, or around 50-100 CPU cycles, per VMA.

In addition, I applied the sealing to 5.10 kernel:
The first test (measuring time)
syscall__	vmas	t	tmseal	delta_ns	per_vma	%
munmap__	1	357	390	33	33	109%
munmap__	2	442	463	21	11	105%
munmap__	4	614	634	20	5	103%
munmap__	8	1017	1137	120	15	112%
munmap__	16	1889	2153	263	16	114%
munmap__	32	4109	4088	-21	-1	99%
mprotect	1	235	227	-7	-7	97%
mprotect	2	495	464	-30	-15	94%
mprotect	4	741	764	24	6	103%
mprotect	8	1434	1437	2	0	100%
mprotect	16	2958	2991	33	2	101%
mprotect	32	6431	6608	177	6	103%
madvise_	1	191	208	16	16	109%
madvise_	2	300	324	24	12	108%
madvise_	4	450	473	23	6	105%
madvise_	8	753	806	53	7	107%
madvise_	16	1467	1592	125	8	108%
madvise_	32	2795	3405	610	19	122%
					
The second test (measuring cpu cycle)
syscall__	nbr_vma	cpu	cmseal	delta_cpu	per_vma	%
munmap__	1	684	715	31	31	105%
munmap__	2	861	898	38	19	104%
munmap__	4	1183	1235	51	13	104%
munmap__	8	1999	2045	46	6	102%
munmap__	16	3839	3816	-23	-1	99%
munmap__	32	7672	7887	216	7	103%
mprotect	1	397	443	46	46	112%
mprotect	2	738	788	50	25	107%
mprotect	4	1221	1256	35	9	103%
mprotect	8	2356	2429	72	9	103%
mprotect	16	4961	4935	-26	-2	99%
mprotect	32	9882	10172	291	9	103%
madvise_	1	351	380	29	29	108%
madvise_	2	565	615	49	25	109%
madvise_	4	872	933	61	15	107%
madvise_	8	1508	1640	132	16	109%
madvise_	16	3078	3323	245	15	108%
madvise_	32	5893	6704	811	25	114%

For 5.10 kernel, sealing check adds 0-15 ns in time, or 10-30
CPU cycles, there is even decrease in some cases.

It might be interesting to compare 5.10 and 6.8 kernel
The first test (measuring time)
syscall__	vmas	t_5_10	t_6_8	delta_ns	per_vma	%
munmap__	1	357	909	552	552	254%
munmap__	2	442	1398	956	478	316%
munmap__	4	614	2444	1830	458	398%
munmap__	8	1017	4029	3012	377	396%
munmap__	16	1889	6647	4758	297	352%
munmap__	32	4109	11811	7702	241	287%
mprotect	1	235	439	204	204	187%
mprotect	2	495	1659	1164	582	335%
mprotect	4	741	3747	3006	752	506%
mprotect	8	1434	6755	5320	665	471%
mprotect	16	2958	13748	10790	674	465%
mprotect	32	6431	27827	21397	669	433%
madvise_	1	191	240	49	49	125%
madvise_	2	300	366	67	33	122%
madvise_	4	450	623	173	43	138%
madvise_	8	753	1110	357	45	147%
madvise_	16	1467	2127	660	41	145%
madvise_	32	2795	4109	1314	41	147%

The second test (measuring cpu cycle)
syscall__	vmas	cpu_5_10	c_6_8	delta_cpu	per_vma	%
munmap__	1	684	1790	1106	1106	262%
munmap__	2	861	2819	1958	979	327%
munmap__	4	1183	4959	3776	944	419%
munmap__	8	1999	8262	6263	783	413%
munmap__	16	3839	13099	9260	579	341%
munmap__	32	7672	23221	15549	486	303%
mprotect	1	397	906	509	509	228%
mprotect	2	738	3019	2281	1140	409%
mprotect	4	1221	6149	4929	1232	504%
mprotect	8	2356	9978	7622	953	423%
mprotect	16	4961	20448	15487	968	412%
mprotect	32	9882	40972	31091	972	415%
madvise_	1	351	434	82	82	123%
madvise_	2	565	752	186	93	133%
madvise_	4	872	1313	442	110	151%
madvise_	8	1508	2271	763	95	151%
madvise_	16	3078	4312	1234	77	140%
madvise_	32	5893	8376	2483	78	142%

From 5.10 to 6.8
munmap: added 250-550 ns in time, or 500-1100 in cpu cycle, per vma.
mprotect: added 200-750 ns in time, or 500-1200 in cpu cycle, per vma.
madvise: added 33-50 ns in time, or 70-110 in cpu cycle, per vma.

In comparison to mseal, which adds 20-40 ns or 50-100 CPU cycles, the
increase from 5.10 to 6.8 is significantly larger, approximately ten times
greater for munmap and mprotect.

When I discuss the mm performance with Brian Makin, an engineer who worked
on performance, it was brought to my attention that such performance
benchmarks, which measuring millions of mm syscall in a tight loop, may
not accurately reflect real-world scenarios, such as that of a database
service.  Also this is tested using a single HW and ChromeOS, the data
from another HW or distribution might be different.  It might be best to
take this data with a grain of salt.


This patch (of 5):

Wire up mseal syscall for all architectures.

Link: https://lkml.kernel.org/r/20240415163527.626541-1-jeffxu@chromium.org
Link: https://lkml.kernel.org/r/20240415163527.626541-2-jeffxu@chromium.org
Signed-off-by: Jeff Xu <jeffxu@chromium.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Jann Horn <jannh@google.com> [Bug #2]
Cc: Jeff Xu <jeffxu@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Jorge Lucangeli Obes <jorgelo@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Stephen Röttger <sroettger@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Amer Al Shanawany <amer.shanawany@gmail.com>
Cc: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-05-23 19:40:26 -07:00
Dongli Zhang
a6c11c0a52 genirq/cpuhotplug, x86/vector: Prevent vector leak during CPU offline
The absence of IRQD_MOVE_PCNTXT prevents immediate effectiveness of
interrupt affinity reconfiguration via procfs. Instead, the change is
deferred until the next instance of the interrupt being triggered on the
original CPU.

When the interrupt next triggers on the original CPU, the new affinity is
enforced within __irq_move_irq(). A vector is allocated from the new CPU,
but the old vector on the original CPU remains and is not immediately
reclaimed. Instead, apicd->move_in_progress is flagged, and the reclaiming
process is delayed until the next trigger of the interrupt on the new CPU.

Upon the subsequent triggering of the interrupt on the new CPU,
irq_complete_move() adds a task to the old CPU's vector_cleanup list if it
remains online. Subsequently, the timer on the old CPU iterates over its
vector_cleanup list, reclaiming old vectors.

However, a rare scenario arises if the old CPU is outgoing before the
interrupt triggers again on the new CPU.

In that case irq_force_complete_move() is not invoked on the outgoing CPU
to reclaim the old apicd->prev_vector because the interrupt isn't currently
affine to the outgoing CPU, and irq_needs_fixup() returns false. Even
though __vector_schedule_cleanup() is later called on the new CPU, it
doesn't reclaim apicd->prev_vector; instead, it simply resets both
apicd->move_in_progress and apicd->prev_vector to 0.

As a result, the vector remains unreclaimed in vector_matrix, leading to a
CPU vector leak.

To address this issue, move the invocation of irq_force_complete_move()
before the irq_needs_fixup() call to reclaim apicd->prev_vector, if the
interrupt is currently or used to be affine to the outgoing CPU.

Additionally, reclaim the vector in __vector_schedule_cleanup() as well,
following a warning message, although theoretically it should never see
apicd->move_in_progress with apicd->prev_cpu pointing to an offline CPU.

Fixes: f0383c24b4 ("genirq/cpuhotplug: Add support for cleaning up move in progress")
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240522220218.162423-1-dongli.zhang@oracle.com
2024-05-23 21:51:50 +02:00
Linus Torvalds
d6a326d694 tracing: Remove second argument of __assign_str()
The __assign_str() macro logic of the TRACE_EVENT() macro was optimized so
 that it no longer needs the second argument. The __assign_str() is always
 matched with __string() field that takes a field name and the source for
 that field:
 
   __string(field, source)
 
 The TRACE_EVENT() macro logic will save off the source value and then use
 that value to copy into the ring buffer via the __assign_str(). Before
 commit c1fa617cae ("tracing: Rework __assign_str() and __string() to not
 duplicate getting the string"), the __assign_str() needed the second
 argument which would perform the same logic as the __string() source
 parameter did. Not only would this add overhead, but it was error prone as
 if the __assign_str() source produced something different, it may not have
 allocated enough for the string in the ring buffer (as the __string()
 source was used to determine how much to allocate)
 
 Now that the __assign_str() just uses the same string that was used in
 __string() it no longer needs the source parameter. It can now be removed.
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Merge tag 'trace-assign-str-v6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing cleanup from Steven Rostedt:
 "Remove second argument of __assign_str()

  The __assign_str() macro logic of the TRACE_EVENT() macro was
  optimized so that it no longer needs the second argument. The
  __assign_str() is always matched with __string() field that takes a
  field name and the source for that field:

    __string(field, source)

  The TRACE_EVENT() macro logic will save off the source value and then
  use that value to copy into the ring buffer via the __assign_str().

  Before commit c1fa617cae ("tracing: Rework __assign_str() and
  __string() to not duplicate getting the string"), the __assign_str()
  needed the second argument which would perform the same logic as the
  __string() source parameter did. Not only would this add overhead, but
  it was error prone as if the __assign_str() source produced something
  different, it may not have allocated enough for the string in the ring
  buffer (as the __string() source was used to determine how much to
  allocate)

  Now that the __assign_str() just uses the same string that was used in
  __string() it no longer needs the source parameter. It can now be
  removed"

* tag 'trace-assign-str-v6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/treewide: Remove second parameter of __assign_str()
2024-05-23 12:28:01 -07:00
Sean Christopherson
b4bd556467 KVM: SVM: WARN on vNMI + NMI window iff NMIs are outright masked
When requesting an NMI window, WARN on vNMI support being enabled if and
only if NMIs are actually masked, i.e. if the vCPU is already handling an
NMI.  KVM's ABI for NMIs that arrive simultanesouly (from KVM's point of
view) is to inject one NMI and pend the other.  When using vNMI, KVM pends
the second NMI simply by setting V_NMI_PENDING, and lets the CPU do the
rest (hardware automatically sets V_NMI_BLOCKING when an NMI is injected).

However, if KVM can't immediately inject an NMI, e.g. because the vCPU is
in an STI shadow or is running with GIF=0, then KVM will request an NMI
window and trigger the WARN (but still function correctly).

Whether or not the GIF=0 case makes sense is debatable, as the intent of
KVM's behavior is to provide functionality that is as close to real
hardware as possible.  E.g. if two NMIs are sent in quick succession, the
probability of both NMIs arriving in an STI shadow is infinitesimally low
on real hardware, but significantly larger in a virtual environment, e.g.
if the vCPU is preempted in the STI shadow.  For GIF=0, the argument isn't
as clear cut, because the window where two NMIs can collide is much larger
in bare metal (though still small).

That said, KVM should not have divergent behavior for the GIF=0 case based
on whether or not vNMI support is enabled.  And KVM has allowed
simultaneous NMIs with GIF=0 for over a decade, since commit 7460fb4a34
("KVM: Fix simultaneous NMIs").  I.e. KVM's GIF=0 handling shouldn't be
modified without a *really* good reason to do so, and if KVM's behavior
were to be modified, it should be done irrespective of vNMI support.

Fixes: fa4c027a79 ("KVM: x86: Add support for SVM's Virtual NMI")
Cc: stable@vger.kernel.org
Cc: Santosh Shukla <Santosh.Shukla@amd.com>
Cc: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20240522021435.1684366-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-05-23 12:34:44 -04:00
Sean Christopherson
76d5363c20 KVM: x86: Force KVM_WERROR if the global WERROR is enabled
Force KVM_WERROR if the global WERROR is enabled to avoid pestering the
user about a Kconfig that will ultimately be ignored.  Force KVM_WERROR
instead of making it mutually exclusive with WERROR to avoid generating a
.config builds KVM with -Werror, but has KVM_WERROR=n.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20240517180341.974251-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-05-23 12:33:31 -04:00
Sean Christopherson
6af6142e3a KVM: x86: Disable KVM_INTEL_PROVE_VE by default
Disable KVM's "prove #VE" support by default, as it provides no functional
value, and even its sanity checking benefits are relatively limited.  I.e.
it should be fully opt-in even on debug kernels, especially since EPT
Violation #VE suppression appears to be buggy on some CPUs.

Opportunistically add a line in the help text to make it abundantly clear
that KVM_INTEL_PROVE_VE should never be enabled in a production
environment.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20240518000430.1118488-10-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-05-23 12:33:15 -04:00
Sean Christopherson
a5dc0c9b55 KVM: VMX: Enumerate EPT Violation #VE support in /proc/cpuinfo
Don't suppress printing EPT_VIOLATION_VE in /proc/cpuinfo, knowing whether
or not KVM_INTEL_PROVE_VE actually does anything is extremely valuable.
A privileged user can get at the information by reading the raw MSR, but
the whole point of the VMX flags is to avoid needing to glean information
from raw MSR reads.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20240518000430.1118488-9-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-05-23 12:28:49 -04:00
Sean Christopherson
bca99c0356 KVM: x86/mmu: Print SPTEs on unexpected #VE
Print the SPTEs that correspond to the faulting GPA on an unexpected EPT
Violation #VE to help the user debug failures, e.g. to pinpoint which SPTE
didn't have SUPPRESS_VE set.

Opportunistically assert that the underlying exit reason was indeed an EPT
Violation, as the CPU has *really* gone off the rails if a #VE occurs due
to a completely unexpected exit reason.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20240518000430.1118488-7-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-05-23 12:28:45 -04:00