Armv8.7 introduces single-copy atomic 64-byte loads and stores
instructions and its variants named under FEAT_{LS64, LS64_V}.
These features are identified by ID_AA64ISAR1_EL1.LS64 and the
use of such instructions in userspace (EL0) can be trapped.
As st64bv (FEAT_LS64_V) and st64bv0 (FEAT_LS64_ACCDATA) can not be tell
apart, FEAT_LS64 and FEAT_LS64_ACCDATA which will be supported in later
patch will be exported to userspace, FEAT_LS64_V will be enabled only
in kernel.
In order to support the use of corresponding instructions in userspace:
- Make ID_AA64ISAR1_EL1.LS64 visbile to userspace
- Add identifying and enabling in the cpufeature list
- Expose these support of these features to userspace through HWCAP3
and cpuinfo
ld64b/st64b (FEAT_LS64) and st64bv (FEAT_LS64_V) is intended for
special memory (device memory) so requires support by the CPU, system
and target memory location (device that support these instructions).
The HWCAP3_LS64, implies the support of CPU and system (since no
identification method from system, so SoC vendors should advertise
support in the CPU if system also support them).
Otherwise for ld64b/st64b the atomicity may not be guaranteed or a
DABT will be generated, so users (probably userspace driver developer)
should make sure the target memory (device) also have the support.
For st64bv 0xffffffffffffffff will be returned as status result for
unsupported memory so user should check it.
Document the restrictions along with HWCAP3_LS64.
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Oliver Upton <oupton@kernel.org>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Zhou Wang <wangzhou1@hisilicon.com>
Signed-off-by: Will Deacon <will@kernel.org>
FEAT_LSFE (Large System Float Extension), providing atomic floating point
memory operations, is optional from v9.5. This feature adds no new
architectural stare and we have no immediate use for it in the kernel so
simply provide a hwcap for it to support discovery by userspace.
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
If FEAT_MTE_TAGGED_FAR (Armv8.9) is supported, bits 63:60 of the fault address
are preserved in response to synchronous tag check faults (SEGV_MTESERR).
This patch modifies below to support this feature:
- Use the original FAR_EL1 value when an MTE tag check fault occurs,
if ARM64_MTE_FAR is supported so that not only logical tag
(bits 59:56) but also address tag (bits 63:60] being reported too.
- Add HWCAP for mtefar to let user know bits 63:60 includes
address tag information when when FEAT_MTE_TAGGED_FAR is supported.
Applications that require this information should install
a signal handler with the SA_EXPOSE_TAGBITS flag.
While this introduces a minor ABI change,
most applications do not set this flag and therefore will not be affected.
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
Link: https://lore.kernel.org/r/20250618084513.1761345-3-yeoreum.yun@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* for-next/misc:
arm64/cpuinfo: only show one cpu's info in c_show()
arm64: Extend pr_crit message on invalid FDT
arm64: Kconfig: remove unnecessary selection of CRC32
arm64: Add missing includes for mem_encrypt
Currently, when ARM64 displays CPU information, every call to c_show()
assembles all CPU information. However, as the number of CPUs increases,
this can lead to insufficient buffer space due to excessive assembly in
a single call, causing repeated expansion and multiple calls to c_show().
To prevent this invalid c_show() call, only one CPU's information is
assembled each time c_show() is called.
Signed-off-by: Ye Bin <yebin10@huawei.com>
Link: https://lore.kernel.org/r/20250421062947.4072855-1-yebin@huaweicloud.com
Signed-off-by: Will Deacon <will@kernel.org>
The KVM PV ABI recently added a feature that allows the VM to discover
the set of physical CPU implementations, identified by a tuple of
{MIDR_EL1, REVIDR_EL1, AIDR_EL1}. Unlike other KVM PV features, the
expectation is that the VMM implements the hypercall instead of KVM as
it has the authoritative view of where the VM gets scheduled.
To do this the VMM needs to know the values of these registers on any
CPU in the system. While MIDR_EL1 and REVIDR_EL1 are already exposed,
AIDR_EL1 is not. Provide it in sysfs along with the other identification
registers.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/20250403231626.3181116-1-oliver.upton@linux.dev
Signed-off-by: Will Deacon <will@kernel.org>
In commit 892f7237b3 ("arm64: Delay initialisation of
cpuinfo_arm64::reg_{zcr,smcr}") we moved access to ZCR, SMCR and SMIDR
later in the boot process in order to ensure that we don't attempt to
interact with them if SVE or SME is disabled on the command line.
Unfortunately when initialising the boot CPU in init_cpu_features() we work
on a copy of the struct cpuinfo_arm64 for the boot CPU used only during
boot, not the percpu copy used by the sysfs code. The expectation of the
feature identification code was that the ID registers would be read in
__cpuinfo_store_cpu() and the values not modified by init_cpu_features().
The main reason for the original change was to avoid early accesses to
ZCR on practical systems that were seen shipping with SVE reported in ID
registers but traps enabled at EL3 and handled as fatal errors, SME was
rolled in due to the similarity with SVE. Since then we have removed the
early accesses to ZCR and SMCR in commits:
abef0695f9 ("arm64/sve: Remove ZCR pseudo register from cpufeature code")
391208485c ("arm64/sve: Remove SMCR pseudo register from cpufeature code")
so only the SMIDR_EL1 part of the change remains. Since SMIDR_EL1 is
only trapped via FEAT_IDST and not the SME trap it is less likely to be
affected by similar issues, and the factors that lead to issues with SVE
are less likely to apply to SME.
Since we have not yet seen practical SME systems that need to use a
command line override (and are only just beginning to see SME systems at
all) and the ID register read is much more likely to be safe let's just
store SMIDR_EL1 along with all the other ID register reads in
__cpuinfo_store_cpu().
This issue wasn't apparent when testing on emulated platforms that do not
report values in SMIDR_EL1.
Fixes: 892f7237b3 ("arm64: Delay initialisation of cpuinfo_arm64::reg_{zcr,smcr}")
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20241217-arm64-fix-boot-cpu-smidr-v3-1-7be278a85623@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Pull kvm updates from Paolo Bonzini:
"The biggest change here is eliminating the awful idea that KVM had of
essentially guessing which pfns are refcounted pages.
The reason to do so was that KVM needs to map both non-refcounted
pages (for example BARs of VFIO devices) and VM_PFNMAP/VM_MIXMEDMAP
VMAs that contain refcounted pages.
However, the result was security issues in the past, and more recently
the inability to map VM_IO and VM_PFNMAP memory that _is_ backed by
struct page but is not refcounted. In particular this broke virtio-gpu
blob resources (which directly map host graphics buffers into the
guest as "vram" for the virtio-gpu device) with the amdgpu driver,
because amdgpu allocates non-compound higher order pages and the tail
pages could not be mapped into KVM.
This requires adjusting all uses of struct page in the
per-architecture code, to always work on the pfn whenever possible.
The large series that did this, from David Stevens and Sean
Christopherson, also cleaned up substantially the set of functions
that provided arch code with the pfn for a host virtual addresses.
The previous maze of twisty little passages, all different, is
replaced by five functions (__gfn_to_page, __kvm_faultin_pfn, the
non-__ versions of these two, and kvm_prefetch_pages) saving almost
200 lines of code.
ARM:
- Support for stage-1 permission indirection (FEAT_S1PIE) and
permission overlays (FEAT_S1POE), including nested virt + the
emulated page table walker
- Introduce PSCI SYSTEM_OFF2 support to KVM + client driver. This
call was introduced in PSCIv1.3 as a mechanism to request
hibernation, similar to the S4 state in ACPI
- Explicitly trap + hide FEAT_MPAM (QoS controls) from KVM guests. As
part of it, introduce trivial initialization of the host's MPAM
context so KVM can use the corresponding traps
- PMU support under nested virtualization, honoring the guest
hypervisor's trap configuration and event filtering when running a
nested guest
- Fixes to vgic ITS serialization where stale device/interrupt table
entries are not zeroed when the mapping is invalidated by the VM
- Avoid emulated MMIO completion if userspace has requested
synchronous external abort injection
- Various fixes and cleanups affecting pKVM, vCPU initialization, and
selftests
LoongArch:
- Add iocsr and mmio bus simulation in kernel.
- Add in-kernel interrupt controller emulation.
- Add support for virtualization extensions to the eiointc irqchip.
PPC:
- Drop lingering and utterly obsolete references to PPC970 KVM, which
was removed 10 years ago.
- Fix incorrect documentation references to non-existing ioctls
RISC-V:
- Accelerate KVM RISC-V when running as a guest
- Perf support to collect KVM guest statistics from host side
s390:
- New selftests: more ucontrol selftests and CPU model sanity checks
- Support for the gen17 CPU model
- List registers supported by KVM_GET/SET_ONE_REG in the
documentation
x86:
- Cleanup KVM's handling of Accessed and Dirty bits to dedup code,
improve documentation, harden against unexpected changes.
Even if the hardware A/D tracking is disabled, it is possible to
use the hardware-defined A/D bits to track if a PFN is Accessed
and/or Dirty, and that removes a lot of special cases.
- Elide TLB flushes when aging secondary PTEs, as has been done in
x86's primary MMU for over 10 years.
- Recover huge pages in-place in the TDP MMU when dirty page logging
is toggled off, instead of zapping them and waiting until the page
is re-accessed to create a huge mapping. This reduces vCPU jitter.
- Batch TLB flushes when dirty page logging is toggled off. This
reduces the time it takes to disable dirty logging by ~3x.
- Remove the shrinker that was (poorly) attempting to reclaim shadow
page tables in low-memory situations.
- Clean up and optimize KVM's handling of writes to
MSR_IA32_APICBASE.
- Advertise CPUIDs for new instructions in Clearwater Forest
- Quirk KVM's misguided behavior of initialized certain feature MSRs
to their maximum supported feature set, which can result in KVM
creating invalid vCPU state. E.g. initializing PERF_CAPABILITIES to
a non-zero value results in the vCPU having invalid state if
userspace hides PDCM from the guest, which in turn can lead to
save/restore failures.
- Fix KVM's handling of non-canonical checks for vCPUs that support
LA57 to better follow the "architecture", in quotes because the
actual behavior is poorly documented. E.g. most MSR writes and
descriptor table loads ignore CR4.LA57 and operate purely on
whether the CPU supports LA57.
- Bypass the register cache when querying CPL from kvm_sched_out(),
as filling the cache from IRQ context is generally unsafe; harden
the cache accessors to try to prevent similar issues from occuring
in the future. The issue that triggered this change was already
fixed in 6.12, but was still kinda latent.
- Advertise AMD_IBPB_RET to userspace, and fix a related bug where
KVM over-advertises SPEC_CTRL when trying to support cross-vendor
VMs.
- Minor cleanups
- Switch hugepage recovery thread to use vhost_task.
These kthreads can consume significant amounts of CPU time on
behalf of a VM or in response to how the VM behaves (for example
how it accesses its memory); therefore KVM tried to place the
thread in the VM's cgroups and charge the CPU time consumed by that
work to the VM's container.
However the kthreads did not process SIGSTOP/SIGCONT, and therefore
cgroups which had KVM instances inside could not complete freezing.
Fix this by replacing the kthread with a PF_USER_WORKER thread, via
the vhost_task abstraction. Another 100+ lines removed, with
generally better behavior too like having these threads properly
parented in the process tree.
- Revert a workaround for an old CPU erratum (Nehalem/Westmere) that
didn't really work; there was really nothing to work around anyway:
the broken patch was meant to fix nested virtualization, but the
PERF_GLOBAL_CTRL MSR is virtualized and therefore unaffected by the
erratum.
- Fix 6.12 regression where CONFIG_KVM will be built as a module even
if asked to be builtin, as long as neither KVM_INTEL nor KVM_AMD is
'y'.
x86 selftests:
- x86 selftests can now use AVX.
Documentation:
- Use rST internal links
- Reorganize the introduction to the API document
Generic:
- Protect vcpu->pid accesses outside of vcpu->mutex with a rwlock
instead of RCU, so that running a vCPU on a different task doesn't
encounter long due to having to wait for all CPUs become quiescent.
In general both reads and writes are rare, but userspace that
supports confidential computing is introducing the use of "helper"
vCPUs that may jump from one host processor to another. Those will
be very happy to trigger a synchronize_rcu(), and the effect on
performance is quite the disaster"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (298 commits)
KVM: x86: Break CONFIG_KVM_X86's direct dependency on KVM_INTEL || KVM_AMD
KVM: x86: add back X86_LOCAL_APIC dependency
Revert "KVM: VMX: Move LOAD_IA32_PERF_GLOBAL_CTRL errata handling out of setup_vmcs_config()"
KVM: x86: switch hugepage recovery thread to vhost_task
KVM: x86: expose MSR_PLATFORM_INFO as a feature MSR
x86: KVM: Advertise CPUIDs for new instructions in Clearwater Forest
Documentation: KVM: fix malformed table
irqchip/loongson-eiointc: Add virt extension support
LoongArch: KVM: Add irqfd support
LoongArch: KVM: Add PCHPIC user mode read and write functions
LoongArch: KVM: Add PCHPIC read and write functions
LoongArch: KVM: Add PCHPIC device support
LoongArch: KVM: Add EIOINTC user mode read and write functions
LoongArch: KVM: Add EIOINTC read and write functions
LoongArch: KVM: Add EIOINTC device support
LoongArch: KVM: Add IPI user mode read and write function
LoongArch: KVM: Add IPI read and write function
LoongArch: KVM: Add IPI device support
LoongArch: KVM: Add iocsr and mmio bus simulation in kernel
KVM: arm64: Pass on SVE mapping failures
...
ARMv8.4 adds support for 'Memory Partitioning And Monitoring' (MPAM)
which describes an interface to cache and bandwidth controls wherever
they appear in the system.
Add support to detect MPAM. Like SVE, MPAM has an extra id register that
describes some more properties, including the virtualisation support,
which is optional. Detect this separately so we can detect
mismatched/insane systems, but still use MPAM on the host even if the
virtualisation support is missing.
MPAM needs enabling at the highest implemented exception level, otherwise
the register accesses trap. The 'enabled' flag is accessible to lower
exception levels, but its in a register that traps when MPAM isn't enabled.
The cpufeature 'matches' hook is extended to test this on one of the
CPUs, so that firmware can emulate MPAM as disabled if it is reserved
for use by secure world.
Secondary CPUs that appear late could trip cpufeature's 'lower safe'
behaviour after the MPAM properties have been advertised to user-space.
Add a verify call to ensure late secondaries match the existing CPUs.
(If you have a boot failure that bisects here its likely your CPUs
advertise MPAM in the id registers, but firmware failed to either enable
or MPAM, or emulate the trap as if it were disabled)
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20241030160317.2528209-4-joey.gouly@arm.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
* for-next/poe: (31 commits)
arm64: pkeys: remove redundant WARN
kselftest/arm64: Add test case for POR_EL0 signal frame records
kselftest/arm64: parse POE_MAGIC in a signal frame
kselftest/arm64: add HWCAP test for FEAT_S1POE
selftests: mm: make protection_keys test work on arm64
selftests: mm: move fpregs printing
kselftest/arm64: move get_header()
arm64: add Permission Overlay Extension Kconfig
arm64: enable PKEY support for CPUs with S1POE
arm64: enable POE and PIE to coexist
arm64/ptrace: add support for FEAT_POE
arm64: add POE signal support
arm64: implement PKEYS support
arm64: add pte_access_permitted_no_overlay()
arm64: handle PKEY/POE faults
arm64: mask out POIndex when modifying a PTE
arm64: convert protection key into vm_flags and pgprot values
arm64: add POIndex defines
arm64: re-order MTE VM_ flags
arm64: enable the Permission Overlay Extension for EL0
...
'struct kobj_type' is not modified. It is only used in kobject_init()
which takes a 'const struct kobj_type *ktype' parameter.
Constifying this structure moves some data to a read-only section,
so increase over all security.
On a x86_64, compiled with arm defconfig:
Before:
======
text data bss dec hex filename
5602 548 352 6502 1966 arch/arm64/kernel/cpuinfo.o
After:
======
text data bss dec hex filename
5650 500 352 6502 1966 arch/arm64/kernel/cpuinfo.o
Signed-off-by: Huang Xiaojia <huangxiaojia2@huawei.com>
Link: https://lore.kernel.org/r/20240826151250.3500302-1-huangxiaojia2@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>
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
...
FEAT_LRCPC3 adds more instructions to support the Release Consistency model.
Add a HWCAP so that userspace can make decisions about instructions it can use.
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20230919162757.2707023-2-joey.gouly@arm.com
[catalin.marinas@arm.com: change the HWCAP number]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Yicong YangandWill Deacon
Mark BrownandWill Deacon
Yeoreum YunandCatalin Marinas
Xi RuoyaoandWill Deacon
Ye BinandWill Deacon
Oliver UptonandWill Deacon
Linus Torvalds
James MorseandOliver Upton
Joey GoulyandWill Deacon
Huang XiaojiaandWill Deacon
Marc ZyngierandOliver Upton