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linux/arch/x86/kvm/cpuid.c
Linus Torvalds 09d1c6a80f Generic: 
- Use memdup_array_user() to harden against overflow.
 
 - Unconditionally advertise KVM_CAP_DEVICE_CTRL for all architectures.
 
 - Clean up Kconfigs that all KVM architectures were selecting
 
 - New functionality around "guest_memfd", a new userspace API that
   creates an anonymous file and returns a file descriptor that refers
   to it.  guest_memfd files are bound to their owning virtual machine,
   cannot be mapped, read, or written by userspace, and cannot be resized.
   guest_memfd files do however support PUNCH_HOLE, which can be used to
   switch a memory area between guest_memfd and regular anonymous memory.
 
 - New ioctl KVM_SET_MEMORY_ATTRIBUTES allowing userspace to specify
   per-page attributes for a given page of guest memory; right now the
   only attribute is whether the guest expects to access memory via
   guest_memfd or not, which in Confidential SVMs backed by SEV-SNP,
   TDX or ARM64 pKVM is checked by firmware or hypervisor that guarantees
   confidentiality (AMD PSP, Intel TDX module, or EL2 in the case of pKVM).
 
 x86:
 
 - Support for "software-protected VMs" that can use the new guest_memfd
   and page attributes infrastructure.  This is mostly useful for testing,
   since there is no pKVM-like infrastructure to provide a meaningfully
   reduced TCB.
 
 - Fix a relatively benign off-by-one error when splitting huge pages during
   CLEAR_DIRTY_LOG.
 
 - Fix a bug where KVM could incorrectly test-and-clear dirty bits in non-leaf
   TDP MMU SPTEs if a racing thread replaces a huge SPTE with a non-huge SPTE.
 
 - Use more generic lockdep assertions in paths that don't actually care
   about whether the caller is a reader or a writer.
 
 - let Xen guests opt out of having PV clock reported as "based on a stable TSC",
   because some of them don't expect the "TSC stable" bit (added to the pvclock
   ABI by KVM, but never set by Xen) to be set.
 
 - Revert a bogus, made-up nested SVM consistency check for TLB_CONTROL.
 
 - Advertise flush-by-ASID support for nSVM unconditionally, as KVM always
   flushes on nested transitions, i.e. always satisfies flush requests.  This
   allows running bleeding edge versions of VMware Workstation on top of KVM.
 
 - Sanity check that the CPU supports flush-by-ASID when enabling SEV support.
 
 - On AMD machines with vNMI, always rely on hardware instead of intercepting
   IRET in some cases to detect unmasking of NMIs
 
 - Support for virtualizing Linear Address Masking (LAM)
 
 - Fix a variety of vPMU bugs where KVM fail to stop/reset counters and other state
   prior to refreshing the vPMU model.
 
 - Fix a double-overflow PMU bug by tracking emulated counter events using a
   dedicated field instead of snapshotting the "previous" counter.  If the
   hardware PMC count triggers overflow that is recognized in the same VM-Exit
   that KVM manually bumps an event count, KVM would pend PMIs for both the
   hardware-triggered overflow and for KVM-triggered overflow.
 
 - Turn off KVM_WERROR by default for all configs so that it's not
   inadvertantly enabled by non-KVM developers, which can be problematic for
   subsystems that require no regressions for W=1 builds.
 
 - Advertise all of the host-supported CPUID bits that enumerate IA32_SPEC_CTRL
   "features".
 
 - Don't force a masterclock update when a vCPU synchronizes to the current TSC
   generation, as updating the masterclock can cause kvmclock's time to "jump"
   unexpectedly, e.g. when userspace hotplugs a pre-created vCPU.
 
 - Use RIP-relative address to read kvm_rebooting in the VM-Enter fault paths,
   partly as a super minor optimization, but mostly to make KVM play nice with
   position independent executable builds.
 
 - Guard KVM-on-HyperV's range-based TLB flush hooks with an #ifdef on
   CONFIG_HYPERV as a minor optimization, and to self-document the code.
 
 - Add CONFIG_KVM_HYPERV to allow disabling KVM support for HyperV "emulation"
   at build time.
 
 ARM64:
 
 - LPA2 support, adding 52bit IPA/PA capability for 4kB and 16kB
   base granule sizes. Branch shared with the arm64 tree.
 
 - Large Fine-Grained Trap rework, bringing some sanity to the
   feature, although there is more to come. This comes with
   a prefix branch shared with the arm64 tree.
 
 - Some additional Nested Virtualization groundwork, mostly
   introducing the NV2 VNCR support and retargetting the NV
   support to that version of the architecture.
 
 - A small set of vgic fixes and associated cleanups.
 
 Loongarch:
 
 - Optimization for memslot hugepage checking
 
 - Cleanup and fix some HW/SW timer issues
 
 - Add LSX/LASX (128bit/256bit SIMD) support
 
 RISC-V:
 
 - KVM_GET_REG_LIST improvement for vector registers
 
 - Generate ISA extension reg_list using macros in get-reg-list selftest
 
 - Support for reporting steal time along with selftest
 
 s390:
 
 - Bugfixes
 
 Selftests:
 
 - Fix an annoying goof where the NX hugepage test prints out garbage
   instead of the magic token needed to run the test.
 
 - Fix build errors when a header is delete/moved due to a missing flag
   in the Makefile.
 
 - Detect if KVM bugged/killed a selftest's VM and print out a helpful
   message instead of complaining that a random ioctl() failed.
 
 - Annotate the guest printf/assert helpers with __printf(), and fix the
   various bugs that were lurking due to lack of said annotation.
 
 There are two non-KVM patches buried in the middle of guest_memfd support:
 
   fs: Rename anon_inode_getfile_secure() and anon_inode_getfd_secure()
   mm: Add AS_UNMOVABLE to mark mapping as completely unmovable
 
 The first is small and mostly suggested-by Christian Brauner; the second
 a bit less so but it was written by an mm person (Vlastimil Babka).
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm updates from Paolo Bonzini:
 "Generic:

   - Use memdup_array_user() to harden against overflow.

   - Unconditionally advertise KVM_CAP_DEVICE_CTRL for all
     architectures.

   - Clean up Kconfigs that all KVM architectures were selecting

   - New functionality around "guest_memfd", a new userspace API that
     creates an anonymous file and returns a file descriptor that refers
     to it. guest_memfd files are bound to their owning virtual machine,
     cannot be mapped, read, or written by userspace, and cannot be
     resized. guest_memfd files do however support PUNCH_HOLE, which can
     be used to switch a memory area between guest_memfd and regular
     anonymous memory.

   - New ioctl KVM_SET_MEMORY_ATTRIBUTES allowing userspace to specify
     per-page attributes for a given page of guest memory; right now the
     only attribute is whether the guest expects to access memory via
     guest_memfd or not, which in Confidential SVMs backed by SEV-SNP,
     TDX or ARM64 pKVM is checked by firmware or hypervisor that
     guarantees confidentiality (AMD PSP, Intel TDX module, or EL2 in
     the case of pKVM).

  x86:

   - Support for "software-protected VMs" that can use the new
     guest_memfd and page attributes infrastructure. This is mostly
     useful for testing, since there is no pKVM-like infrastructure to
     provide a meaningfully reduced TCB.

   - Fix a relatively benign off-by-one error when splitting huge pages
     during CLEAR_DIRTY_LOG.

   - Fix a bug where KVM could incorrectly test-and-clear dirty bits in
     non-leaf TDP MMU SPTEs if a racing thread replaces a huge SPTE with
     a non-huge SPTE.

   - Use more generic lockdep assertions in paths that don't actually
     care about whether the caller is a reader or a writer.

   - let Xen guests opt out of having PV clock reported as "based on a
     stable TSC", because some of them don't expect the "TSC stable" bit
     (added to the pvclock ABI by KVM, but never set by Xen) to be set.

   - Revert a bogus, made-up nested SVM consistency check for
     TLB_CONTROL.

   - Advertise flush-by-ASID support for nSVM unconditionally, as KVM
     always flushes on nested transitions, i.e. always satisfies flush
     requests. This allows running bleeding edge versions of VMware
     Workstation on top of KVM.

   - Sanity check that the CPU supports flush-by-ASID when enabling SEV
     support.

   - On AMD machines with vNMI, always rely on hardware instead of
     intercepting IRET in some cases to detect unmasking of NMIs

   - Support for virtualizing Linear Address Masking (LAM)

   - Fix a variety of vPMU bugs where KVM fail to stop/reset counters
     and other state prior to refreshing the vPMU model.

   - Fix a double-overflow PMU bug by tracking emulated counter events
     using a dedicated field instead of snapshotting the "previous"
     counter. If the hardware PMC count triggers overflow that is
     recognized in the same VM-Exit that KVM manually bumps an event
     count, KVM would pend PMIs for both the hardware-triggered overflow
     and for KVM-triggered overflow.

   - Turn off KVM_WERROR by default for all configs so that it's not
     inadvertantly enabled by non-KVM developers, which can be
     problematic for subsystems that require no regressions for W=1
     builds.

   - Advertise all of the host-supported CPUID bits that enumerate
     IA32_SPEC_CTRL "features".

   - Don't force a masterclock update when a vCPU synchronizes to the
     current TSC generation, as updating the masterclock can cause
     kvmclock's time to "jump" unexpectedly, e.g. when userspace
     hotplugs a pre-created vCPU.

   - Use RIP-relative address to read kvm_rebooting in the VM-Enter
     fault paths, partly as a super minor optimization, but mostly to
     make KVM play nice with position independent executable builds.

   - Guard KVM-on-HyperV's range-based TLB flush hooks with an #ifdef on
     CONFIG_HYPERV as a minor optimization, and to self-document the
     code.

   - Add CONFIG_KVM_HYPERV to allow disabling KVM support for HyperV
     "emulation" at build time.

  ARM64:

   - LPA2 support, adding 52bit IPA/PA capability for 4kB and 16kB base
     granule sizes. Branch shared with the arm64 tree.

   - Large Fine-Grained Trap rework, bringing some sanity to the
     feature, although there is more to come. This comes with a prefix
     branch shared with the arm64 tree.

   - Some additional Nested Virtualization groundwork, mostly
     introducing the NV2 VNCR support and retargetting the NV support to
     that version of the architecture.

   - A small set of vgic fixes and associated cleanups.

  Loongarch:

   - Optimization for memslot hugepage checking

   - Cleanup and fix some HW/SW timer issues

   - Add LSX/LASX (128bit/256bit SIMD) support

  RISC-V:

   - KVM_GET_REG_LIST improvement for vector registers

   - Generate ISA extension reg_list using macros in get-reg-list
     selftest

   - Support for reporting steal time along with selftest

  s390:

   - Bugfixes

  Selftests:

   - Fix an annoying goof where the NX hugepage test prints out garbage
     instead of the magic token needed to run the test.

   - Fix build errors when a header is delete/moved due to a missing
     flag in the Makefile.

   - Detect if KVM bugged/killed a selftest's VM and print out a helpful
     message instead of complaining that a random ioctl() failed.

   - Annotate the guest printf/assert helpers with __printf(), and fix
     the various bugs that were lurking due to lack of said annotation"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (185 commits)
  x86/kvm: Do not try to disable kvmclock if it was not enabled
  KVM: x86: add missing "depends on KVM"
  KVM: fix direction of dependency on MMU notifiers
  KVM: introduce CONFIG_KVM_COMMON
  KVM: arm64: Add missing memory barriers when switching to pKVM's hyp pgd
  KVM: arm64: vgic-its: Avoid potential UAF in LPI translation cache
  RISC-V: KVM: selftests: Add get-reg-list test for STA registers
  RISC-V: KVM: selftests: Add steal_time test support
  RISC-V: KVM: selftests: Add guest_sbi_probe_extension
  RISC-V: KVM: selftests: Move sbi_ecall to processor.c
  RISC-V: KVM: Implement SBI STA extension
  RISC-V: KVM: Add support for SBI STA registers
  RISC-V: KVM: Add support for SBI extension registers
  RISC-V: KVM: Add SBI STA info to vcpu_arch
  RISC-V: KVM: Add steal-update vcpu request
  RISC-V: KVM: Add SBI STA extension skeleton
  RISC-V: paravirt: Implement steal-time support
  RISC-V: Add SBI STA extension definitions
  RISC-V: paravirt: Add skeleton for pv-time support
  RISC-V: KVM: Fix indentation in kvm_riscv_vcpu_set_reg_csr()
  ...
2024-01-17 13:03:37 -08:00

1599 lines
45 KiB
C
Raw Blame History

// SPDX-License-Identifier: GPL-2.0-only
/*
* Kernel-based Virtual Machine driver for Linux
* cpuid support routines
*
* derived from arch/x86/kvm/x86.c
*
* Copyright 2011 Red Hat, Inc. and/or its affiliates.
* Copyright IBM Corporation, 2008
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kvm_host.h>
#include "linux/lockdep.h"
#include <linux/export.h>
#include <linux/vmalloc.h>
#include <linux/uaccess.h>
#include <linux/sched/stat.h>
#include <asm/processor.h>
#include <asm/user.h>
#include <asm/fpu/xstate.h>
#include <asm/sgx.h>
#include <asm/cpuid.h>
#include "cpuid.h"
#include "lapic.h"
#include "mmu.h"
#include "trace.h"
#include "pmu.h"
#include "xen.h"
/*
* Unlike "struct cpuinfo_x86.x86_capability", kvm_cpu_caps doesn't need to be
* aligned to sizeof(unsigned long) because it's not accessed via bitops.
*/
u32 kvm_cpu_caps[NR_KVM_CPU_CAPS] __read_mostly;
EXPORT_SYMBOL_GPL(kvm_cpu_caps);
u32 xstate_required_size(u64 xstate_bv, bool compacted)
{
int feature_bit = 0;
u32 ret = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
xstate_bv &= XFEATURE_MASK_EXTEND;
while (xstate_bv) {
if (xstate_bv & 0x1) {
u32 eax, ebx, ecx, edx, offset;
cpuid_count(0xD, feature_bit, &eax, &ebx, &ecx, &edx);
/* ECX[1]: 64B alignment in compacted form */
if (compacted)
offset = (ecx & 0x2) ? ALIGN(ret, 64) : ret;
else
offset = ebx;
ret = max(ret, offset + eax);
}
xstate_bv >>= 1;
feature_bit++;
}
return ret;
}
#define F feature_bit
/* Scattered Flag - For features that are scattered by cpufeatures.h. */
#define SF(name) \
({ \
BUILD_BUG_ON(X86_FEATURE_##name >= MAX_CPU_FEATURES); \
(boot_cpu_has(X86_FEATURE_##name) ? F(name) : 0); \
})
/*
* Magic value used by KVM when querying userspace-provided CPUID entries and
* doesn't care about the CPIUD index because the index of the function in
* question is not significant. Note, this magic value must have at least one
* bit set in bits[63:32] and must be consumed as a u64 by cpuid_entry2_find()
* to avoid false positives when processing guest CPUID input.
*/
#define KVM_CPUID_INDEX_NOT_SIGNIFICANT -1ull
static inline struct kvm_cpuid_entry2 *cpuid_entry2_find(
struct kvm_cpuid_entry2 *entries, int nent, u32 function, u64 index)
{
struct kvm_cpuid_entry2 *e;
int i;
/*
* KVM has a semi-arbitrary rule that querying the guest's CPUID model
* with IRQs disabled is disallowed. The CPUID model can legitimately
* have over one hundred entries, i.e. the lookup is slow, and IRQs are
* typically disabled in KVM only when KVM is in a performance critical
* path, e.g. the core VM-Enter/VM-Exit run loop. Nothing will break
* if this rule is violated, this assertion is purely to flag potential
* performance issues. If this fires, consider moving the lookup out
* of the hotpath, e.g. by caching information during CPUID updates.
*/
lockdep_assert_irqs_enabled();
for (i = 0; i < nent; i++) {
e = &entries[i];
if (e->function != function)
continue;
/*
* If the index isn't significant, use the first entry with a
* matching function. It's userspace's responsibility to not
* provide "duplicate" entries in all cases.
*/
if (!(e->flags & KVM_CPUID_FLAG_SIGNIFCANT_INDEX) || e->index == index)
return e;
/*
* Similarly, use the first matching entry if KVM is doing a
* lookup (as opposed to emulating CPUID) for a function that's
* architecturally defined as not having a significant index.
*/
if (index == KVM_CPUID_INDEX_NOT_SIGNIFICANT) {
/*
* Direct lookups from KVM should not diverge from what
* KVM defines internally (the architectural behavior).
*/
WARN_ON_ONCE(cpuid_function_is_indexed(function));
return e;
}
}
return NULL;
}
static int kvm_check_cpuid(struct kvm_vcpu *vcpu,
struct kvm_cpuid_entry2 *entries,
int nent)
{
struct kvm_cpuid_entry2 *best;
u64 xfeatures;
/*
* The existing code assumes virtual address is 48-bit or 57-bit in the
* canonical address checks; exit if it is ever changed.
*/
best = cpuid_entry2_find(entries, nent, 0x80000008,
KVM_CPUID_INDEX_NOT_SIGNIFICANT);
if (best) {
int vaddr_bits = (best->eax & 0xff00) >> 8;
if (vaddr_bits != 48 && vaddr_bits != 57 && vaddr_bits != 0)
return -EINVAL;
}
/*
* Exposing dynamic xfeatures to the guest requires additional
* enabling in the FPU, e.g. to expand the guest XSAVE state size.
*/
best = cpuid_entry2_find(entries, nent, 0xd, 0);
if (!best)
return 0;
xfeatures = best->eax | ((u64)best->edx << 32);
xfeatures &= XFEATURE_MASK_USER_DYNAMIC;
if (!xfeatures)
return 0;
return fpu_enable_guest_xfd_features(&vcpu->arch.guest_fpu, xfeatures);
}
/* Check whether the supplied CPUID data is equal to what is already set for the vCPU. */
static int kvm_cpuid_check_equal(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *e2,
int nent)
{
struct kvm_cpuid_entry2 *orig;
int i;
if (nent != vcpu->arch.cpuid_nent)
return -EINVAL;
for (i = 0; i < nent; i++) {
orig = &vcpu->arch.cpuid_entries[i];
if (e2[i].function != orig->function ||
e2[i].index != orig->index ||
e2[i].flags != orig->flags ||
e2[i].eax != orig->eax || e2[i].ebx != orig->ebx ||
e2[i].ecx != orig->ecx || e2[i].edx != orig->edx)
return -EINVAL;
}
return 0;
}
static struct kvm_hypervisor_cpuid kvm_get_hypervisor_cpuid(struct kvm_vcpu *vcpu,
const char *sig)
{
struct kvm_hypervisor_cpuid cpuid = {};
struct kvm_cpuid_entry2 *entry;
u32 base;
for_each_possible_hypervisor_cpuid_base(base) {
entry = kvm_find_cpuid_entry(vcpu, base);
if (entry) {
u32 signature[3];
signature[0] = entry->ebx;
signature[1] = entry->ecx;
signature[2] = entry->edx;
if (!memcmp(signature, sig, sizeof(signature))) {
cpuid.base = base;
cpuid.limit = entry->eax;
break;
}
}
}
return cpuid;
}
static struct kvm_cpuid_entry2 *__kvm_find_kvm_cpuid_features(struct kvm_vcpu *vcpu,
struct kvm_cpuid_entry2 *entries, int nent)
{
u32 base = vcpu->arch.kvm_cpuid.base;
if (!base)
return NULL;
return cpuid_entry2_find(entries, nent, base | KVM_CPUID_FEATURES,
KVM_CPUID_INDEX_NOT_SIGNIFICANT);
}
static struct kvm_cpuid_entry2 *kvm_find_kvm_cpuid_features(struct kvm_vcpu *vcpu)
{
return __kvm_find_kvm_cpuid_features(vcpu, vcpu->arch.cpuid_entries,
vcpu->arch.cpuid_nent);
}
void kvm_update_pv_runtime(struct kvm_vcpu *vcpu)
{
struct kvm_cpuid_entry2 *best = kvm_find_kvm_cpuid_features(vcpu);
/*
* save the feature bitmap to avoid cpuid lookup for every PV
* operation
*/
if (best)
vcpu->arch.pv_cpuid.features = best->eax;
}
/*
* Calculate guest's supported XCR0 taking into account guest CPUID data and
* KVM's supported XCR0 (comprised of host's XCR0 and KVM_SUPPORTED_XCR0).
*/
static u64 cpuid_get_supported_xcr0(struct kvm_cpuid_entry2 *entries, int nent)
{
struct kvm_cpuid_entry2 *best;
best = cpuid_entry2_find(entries, nent, 0xd, 0);
if (!best)
return 0;
return (best->eax | ((u64)best->edx << 32)) & kvm_caps.supported_xcr0;
}
static void __kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *entries,
int nent)
{
struct kvm_cpuid_entry2 *best;
best = cpuid_entry2_find(entries, nent, 1, KVM_CPUID_INDEX_NOT_SIGNIFICANT);
if (best) {
/* Update OSXSAVE bit */
if (boot_cpu_has(X86_FEATURE_XSAVE))
cpuid_entry_change(best, X86_FEATURE_OSXSAVE,
kvm_is_cr4_bit_set(vcpu, X86_CR4_OSXSAVE));
cpuid_entry_change(best, X86_FEATURE_APIC,
vcpu->arch.apic_base & MSR_IA32_APICBASE_ENABLE);
}
best = cpuid_entry2_find(entries, nent, 7, 0);
if (best && boot_cpu_has(X86_FEATURE_PKU) && best->function == 0x7)
cpuid_entry_change(best, X86_FEATURE_OSPKE,
kvm_is_cr4_bit_set(vcpu, X86_CR4_PKE));
best = cpuid_entry2_find(entries, nent, 0xD, 0);
if (best)
best->ebx = xstate_required_size(vcpu->arch.xcr0, false);
best = cpuid_entry2_find(entries, nent, 0xD, 1);
if (best && (cpuid_entry_has(best, X86_FEATURE_XSAVES) ||
cpuid_entry_has(best, X86_FEATURE_XSAVEC)))
best->ebx = xstate_required_size(vcpu->arch.xcr0, true);
best = __kvm_find_kvm_cpuid_features(vcpu, entries, nent);
if (kvm_hlt_in_guest(vcpu->kvm) && best &&
(best->eax & (1 << KVM_FEATURE_PV_UNHALT)))
best->eax &= ~(1 << KVM_FEATURE_PV_UNHALT);
if (!kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT)) {
best = cpuid_entry2_find(entries, nent, 0x1, KVM_CPUID_INDEX_NOT_SIGNIFICANT);
if (best)
cpuid_entry_change(best, X86_FEATURE_MWAIT,
vcpu->arch.ia32_misc_enable_msr &
MSR_IA32_MISC_ENABLE_MWAIT);
}
}
void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu)
{
__kvm_update_cpuid_runtime(vcpu, vcpu->arch.cpuid_entries, vcpu->arch.cpuid_nent);
}
EXPORT_SYMBOL_GPL(kvm_update_cpuid_runtime);
static bool kvm_cpuid_has_hyperv(struct kvm_cpuid_entry2 *entries, int nent)
{
#ifdef CONFIG_KVM_HYPERV
struct kvm_cpuid_entry2 *entry;
entry = cpuid_entry2_find(entries, nent, HYPERV_CPUID_INTERFACE,
KVM_CPUID_INDEX_NOT_SIGNIFICANT);
return entry && entry->eax == HYPERV_CPUID_SIGNATURE_EAX;
#else
return false;
#endif
}
static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
{
struct kvm_lapic *apic = vcpu->arch.apic;
struct kvm_cpuid_entry2 *best;
bool allow_gbpages;
BUILD_BUG_ON(KVM_NR_GOVERNED_FEATURES > KVM_MAX_NR_GOVERNED_FEATURES);
bitmap_zero(vcpu->arch.governed_features.enabled,
KVM_MAX_NR_GOVERNED_FEATURES);
/*
* If TDP is enabled, let the guest use GBPAGES if they're supported in
* hardware. The hardware page walker doesn't let KVM disable GBPAGES,
* i.e. won't treat them as reserved, and KVM doesn't redo the GVA->GPA
* walk for performance and complexity reasons. Not to mention KVM
* _can't_ solve the problem because GVA->GPA walks aren't visible to
* KVM once a TDP translation is installed. Mimic hardware behavior so
* that KVM's is at least consistent, i.e. doesn't randomly inject #PF.
* If TDP is disabled, honor *only* guest CPUID as KVM has full control
* and can install smaller shadow pages if the host lacks 1GiB support.
*/
allow_gbpages = tdp_enabled ? boot_cpu_has(X86_FEATURE_GBPAGES) :
guest_cpuid_has(vcpu, X86_FEATURE_GBPAGES);
if (allow_gbpages)
kvm_governed_feature_set(vcpu, X86_FEATURE_GBPAGES);
best = kvm_find_cpuid_entry(vcpu, 1);
if (best && apic) {
if (cpuid_entry_has(best, X86_FEATURE_TSC_DEADLINE_TIMER))
apic->lapic_timer.timer_mode_mask = 3 << 17;
else
apic->lapic_timer.timer_mode_mask = 1 << 17;
kvm_apic_set_version(vcpu);
}
vcpu->arch.guest_supported_xcr0 =
cpuid_get_supported_xcr0(vcpu->arch.cpuid_entries, vcpu->arch.cpuid_nent);
kvm_update_pv_runtime(vcpu);
vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu);
vcpu->arch.reserved_gpa_bits = kvm_vcpu_reserved_gpa_bits_raw(vcpu);
kvm_pmu_refresh(vcpu);
vcpu->arch.cr4_guest_rsvd_bits =
__cr4_reserved_bits(guest_cpuid_has, vcpu);
kvm_hv_set_cpuid(vcpu, kvm_cpuid_has_hyperv(vcpu->arch.cpuid_entries,
vcpu->arch.cpuid_nent));
/* Invoke the vendor callback only after the above state is updated. */
static_call(kvm_x86_vcpu_after_set_cpuid)(vcpu);
/*
* Except for the MMU, which needs to do its thing any vendor specific
* adjustments to the reserved GPA bits.
*/
kvm_mmu_after_set_cpuid(vcpu);
}
int cpuid_query_maxphyaddr(struct kvm_vcpu *vcpu)
{
struct kvm_cpuid_entry2 *best;
best = kvm_find_cpuid_entry(vcpu, 0x80000000);
if (!best || best->eax < 0x80000008)
goto not_found;
best = kvm_find_cpuid_entry(vcpu, 0x80000008);
if (best)
return best->eax & 0xff;
not_found:
return 36;
}
/*
* This "raw" version returns the reserved GPA bits without any adjustments for
* encryption technologies that usurp bits. The raw mask should be used if and
* only if hardware does _not_ strip the usurped bits, e.g. in virtual MTRRs.
*/
u64 kvm_vcpu_reserved_gpa_bits_raw(struct kvm_vcpu *vcpu)
{
return rsvd_bits(cpuid_maxphyaddr(vcpu), 63);
}
static int kvm_set_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *e2,
int nent)
{
int r;
__kvm_update_cpuid_runtime(vcpu, e2, nent);
/*
* KVM does not correctly handle changing guest CPUID after KVM_RUN, as
* MAXPHYADDR, GBPAGES support, AMD reserved bit behavior, etc.. aren't
* tracked in kvm_mmu_page_role. As a result, KVM may miss guest page
* faults due to reusing SPs/SPTEs. In practice no sane VMM mucks with
* the core vCPU model on the fly. It would've been better to forbid any
* KVM_SET_CPUID{,2} calls after KVM_RUN altogether but unfortunately
* some VMMs (e.g. QEMU) reuse vCPU fds for CPU hotplug/unplug and do
* KVM_SET_CPUID{,2} again. To support this legacy behavior, check
* whether the supplied CPUID data is equal to what's already set.
*/
if (kvm_vcpu_has_run(vcpu)) {
r = kvm_cpuid_check_equal(vcpu, e2, nent);
if (r)
return r;
kvfree(e2);
return 0;
}
#ifdef CONFIG_KVM_HYPERV
if (kvm_cpuid_has_hyperv(e2, nent)) {
r = kvm_hv_vcpu_init(vcpu);
if (r)
return r;
}
#endif
r = kvm_check_cpuid(vcpu, e2, nent);
if (r)
return r;
kvfree(vcpu->arch.cpuid_entries);
vcpu->arch.cpuid_entries = e2;
vcpu->arch.cpuid_nent = nent;
vcpu->arch.kvm_cpuid = kvm_get_hypervisor_cpuid(vcpu, KVM_SIGNATURE);
#ifdef CONFIG_KVM_XEN
vcpu->arch.xen.cpuid = kvm_get_hypervisor_cpuid(vcpu, XEN_SIGNATURE);
#endif
kvm_vcpu_after_set_cpuid(vcpu);
return 0;
}
/* when an old userspace process fills a new kernel module */
int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
struct kvm_cpuid *cpuid,
struct kvm_cpuid_entry __user *entries)
{
int r, i;
struct kvm_cpuid_entry *e = NULL;
struct kvm_cpuid_entry2 *e2 = NULL;
if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
return -E2BIG;
if (cpuid->nent) {
e = vmemdup_array_user(entries, cpuid->nent, sizeof(*e));
if (IS_ERR(e))
return PTR_ERR(e);
e2 = kvmalloc_array(cpuid->nent, sizeof(*e2), GFP_KERNEL_ACCOUNT);
if (!e2) {
r = -ENOMEM;
goto out_free_cpuid;
}
}
for (i = 0; i < cpuid->nent; i++) {
e2[i].function = e[i].function;
e2[i].eax = e[i].eax;
e2[i].ebx = e[i].ebx;
e2[i].ecx = e[i].ecx;
e2[i].edx = e[i].edx;
e2[i].index = 0;
e2[i].flags = 0;
e2[i].padding[0] = 0;
e2[i].padding[1] = 0;
e2[i].padding[2] = 0;
}
r = kvm_set_cpuid(vcpu, e2, cpuid->nent);
if (r)
kvfree(e2);
out_free_cpuid:
kvfree(e);
return r;
}
int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
struct kvm_cpuid2 *cpuid,
struct kvm_cpuid_entry2 __user *entries)
{
struct kvm_cpuid_entry2 *e2 = NULL;
int r;
if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
return -E2BIG;
if (cpuid->nent) {
e2 = vmemdup_array_user(entries, cpuid->nent, sizeof(*e2));
if (IS_ERR(e2))
return PTR_ERR(e2);
}
r = kvm_set_cpuid(vcpu, e2, cpuid->nent);
if (r)
kvfree(e2);
return r;
}
int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
struct kvm_cpuid2 *cpuid,
struct kvm_cpuid_entry2 __user *entries)
{
if (cpuid->nent < vcpu->arch.cpuid_nent)
return -E2BIG;
if (copy_to_user(entries, vcpu->arch.cpuid_entries,
vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2)))
return -EFAULT;
cpuid->nent = vcpu->arch.cpuid_nent;
return 0;
}
/* Mask kvm_cpu_caps for @leaf with the raw CPUID capabilities of this CPU. */
static __always_inline void __kvm_cpu_cap_mask(unsigned int leaf)
{
const struct cpuid_reg cpuid = x86_feature_cpuid(leaf * 32);
struct kvm_cpuid_entry2 entry;
reverse_cpuid_check(leaf);
cpuid_count(cpuid.function, cpuid.index,
&entry.eax, &entry.ebx, &entry.ecx, &entry.edx);
kvm_cpu_caps[leaf] &= *__cpuid_entry_get_reg(&entry, cpuid.reg);
}
static __always_inline
void kvm_cpu_cap_init_kvm_defined(enum kvm_only_cpuid_leafs leaf, u32 mask)
{
/* Use kvm_cpu_cap_mask for leafs that aren't KVM-only. */
BUILD_BUG_ON(leaf < NCAPINTS);
kvm_cpu_caps[leaf] = mask;
__kvm_cpu_cap_mask(leaf);
}
static __always_inline void kvm_cpu_cap_mask(enum cpuid_leafs leaf, u32 mask)
{
/* Use kvm_cpu_cap_init_kvm_defined for KVM-only leafs. */
BUILD_BUG_ON(leaf >= NCAPINTS);
kvm_cpu_caps[leaf] &= mask;
__kvm_cpu_cap_mask(leaf);
}
void kvm_set_cpu_caps(void)
{
#ifdef CONFIG_X86_64
unsigned int f_gbpages = F(GBPAGES);
unsigned int f_lm = F(LM);
unsigned int f_xfd = F(XFD);
#else
unsigned int f_gbpages = 0;
unsigned int f_lm = 0;
unsigned int f_xfd = 0;
#endif
memset(kvm_cpu_caps, 0, sizeof(kvm_cpu_caps));
BUILD_BUG_ON(sizeof(kvm_cpu_caps) - (NKVMCAPINTS * sizeof(*kvm_cpu_caps)) >
sizeof(boot_cpu_data.x86_capability));
memcpy(&kvm_cpu_caps, &boot_cpu_data.x86_capability,
sizeof(kvm_cpu_caps) - (NKVMCAPINTS * sizeof(*kvm_cpu_caps)));
kvm_cpu_cap_mask(CPUID_1_ECX,
/*
* NOTE: MONITOR (and MWAIT) are emulated as NOP, but *not*
* advertised to guests via CPUID!
*/
F(XMM3) | F(PCLMULQDQ) | 0 /* DTES64, MONITOR */ |
0 /* DS-CPL, VMX, SMX, EST */ |
0 /* TM2 */ | F(SSSE3) | 0 /* CNXT-ID */ | 0 /* Reserved */ |
F(FMA) | F(CX16) | 0 /* xTPR Update */ | F(PDCM) |
F(PCID) | 0 /* Reserved, DCA */ | F(XMM4_1) |
F(XMM4_2) | F(X2APIC) | F(MOVBE) | F(POPCNT) |
0 /* Reserved*/ | F(AES) | F(XSAVE) | 0 /* OSXSAVE */ | F(AVX) |
F(F16C) | F(RDRAND)
);
/* KVM emulates x2apic in software irrespective of host support. */
kvm_cpu_cap_set(X86_FEATURE_X2APIC);
kvm_cpu_cap_mask(CPUID_1_EDX,
F(FPU) | F(VME) | F(DE) | F(PSE) |
F(TSC) | F(MSR) | F(PAE) | F(MCE) |
F(CX8) | F(APIC) | 0 /* Reserved */ | F(SEP) |
F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
F(PAT) | F(PSE36) | 0 /* PSN */ | F(CLFLUSH) |
0 /* Reserved, DS, ACPI */ | F(MMX) |
F(FXSR) | F(XMM) | F(XMM2) | F(SELFSNOOP) |
0 /* HTT, TM, Reserved, PBE */
);
kvm_cpu_cap_mask(CPUID_7_0_EBX,
F(FSGSBASE) | F(SGX) | F(BMI1) | F(HLE) | F(AVX2) |
F(FDP_EXCPTN_ONLY) | F(SMEP) | F(BMI2) | F(ERMS) | F(INVPCID) |
F(RTM) | F(ZERO_FCS_FDS) | 0 /*MPX*/ | F(AVX512F) |
F(AVX512DQ) | F(RDSEED) | F(ADX) | F(SMAP) | F(AVX512IFMA) |
F(CLFLUSHOPT) | F(CLWB) | 0 /*INTEL_PT*/ | F(AVX512PF) |
F(AVX512ER) | F(AVX512CD) | F(SHA_NI) | F(AVX512BW) |
F(AVX512VL));
kvm_cpu_cap_mask(CPUID_7_ECX,
F(AVX512VBMI) | F(LA57) | F(PKU) | 0 /*OSPKE*/ | F(RDPID) |
F(AVX512_VPOPCNTDQ) | F(UMIP) | F(AVX512_VBMI2) | F(GFNI) |
F(VAES) | F(VPCLMULQDQ) | F(AVX512_VNNI) | F(AVX512_BITALG) |
F(CLDEMOTE) | F(MOVDIRI) | F(MOVDIR64B) | 0 /*WAITPKG*/ |
F(SGX_LC) | F(BUS_LOCK_DETECT)
);
/* Set LA57 based on hardware capability. */
if (cpuid_ecx(7) & F(LA57))
kvm_cpu_cap_set(X86_FEATURE_LA57);
/*
* PKU not yet implemented for shadow paging and requires OSPKE
* to be set on the host. Clear it if that is not the case
*/
if (!tdp_enabled || !boot_cpu_has(X86_FEATURE_OSPKE))
kvm_cpu_cap_clear(X86_FEATURE_PKU);
kvm_cpu_cap_mask(CPUID_7_EDX,
F(AVX512_4VNNIW) | F(AVX512_4FMAPS) | F(SPEC_CTRL) |
F(SPEC_CTRL_SSBD) | F(ARCH_CAPABILITIES) | F(INTEL_STIBP) |
F(MD_CLEAR) | F(AVX512_VP2INTERSECT) | F(FSRM) |
F(SERIALIZE) | F(TSXLDTRK) | F(AVX512_FP16) |
F(AMX_TILE) | F(AMX_INT8) | F(AMX_BF16) | F(FLUSH_L1D)
);
/* TSC_ADJUST and ARCH_CAPABILITIES are emulated in software. */
kvm_cpu_cap_set(X86_FEATURE_TSC_ADJUST);
kvm_cpu_cap_set(X86_FEATURE_ARCH_CAPABILITIES);
if (boot_cpu_has(X86_FEATURE_IBPB) && boot_cpu_has(X86_FEATURE_IBRS))
kvm_cpu_cap_set(X86_FEATURE_SPEC_CTRL);
if (boot_cpu_has(X86_FEATURE_STIBP))
kvm_cpu_cap_set(X86_FEATURE_INTEL_STIBP);
if (boot_cpu_has(X86_FEATURE_AMD_SSBD))
kvm_cpu_cap_set(X86_FEATURE_SPEC_CTRL_SSBD);
kvm_cpu_cap_mask(CPUID_7_1_EAX,
F(AVX_VNNI) | F(AVX512_BF16) | F(CMPCCXADD) |
F(FZRM) | F(FSRS) | F(FSRC) |
F(AMX_FP16) | F(AVX_IFMA) | F(LAM)
);
kvm_cpu_cap_init_kvm_defined(CPUID_7_1_EDX,
F(AVX_VNNI_INT8) | F(AVX_NE_CONVERT) | F(PREFETCHITI) |
F(AMX_COMPLEX)
);
kvm_cpu_cap_init_kvm_defined(CPUID_7_2_EDX,
F(INTEL_PSFD) | F(IPRED_CTRL) | F(RRSBA_CTRL) | F(DDPD_U) |
F(BHI_CTRL) | F(MCDT_NO)
);
kvm_cpu_cap_mask(CPUID_D_1_EAX,
F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | F(XSAVES) | f_xfd
);
kvm_cpu_cap_init_kvm_defined(CPUID_12_EAX,
SF(SGX1) | SF(SGX2) | SF(SGX_EDECCSSA)
);
kvm_cpu_cap_mask(CPUID_8000_0001_ECX,
F(LAHF_LM) | F(CMP_LEGACY) | 0 /*SVM*/ | 0 /* ExtApicSpace */ |
F(CR8_LEGACY) | F(ABM) | F(SSE4A) | F(MISALIGNSSE) |
F(3DNOWPREFETCH) | F(OSVW) | 0 /* IBS */ | F(XOP) |
0 /* SKINIT, WDT, LWP */ | F(FMA4) | F(TBM) |
F(TOPOEXT) | 0 /* PERFCTR_CORE */
);
kvm_cpu_cap_mask(CPUID_8000_0001_EDX,
F(FPU) | F(VME) | F(DE) | F(PSE) |
F(TSC) | F(MSR) | F(PAE) | F(MCE) |
F(CX8) | F(APIC) | 0 /* Reserved */ | F(SYSCALL) |
F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
F(PAT) | F(PSE36) | 0 /* Reserved */ |
F(NX) | 0 /* Reserved */ | F(MMXEXT) | F(MMX) |
F(FXSR) | F(FXSR_OPT) | f_gbpages | F(RDTSCP) |
0 /* Reserved */ | f_lm | F(3DNOWEXT) | F(3DNOW)
);
if (!tdp_enabled && IS_ENABLED(CONFIG_X86_64))
kvm_cpu_cap_set(X86_FEATURE_GBPAGES);
kvm_cpu_cap_init_kvm_defined(CPUID_8000_0007_EDX,
SF(CONSTANT_TSC)
);
kvm_cpu_cap_mask(CPUID_8000_0008_EBX,
F(CLZERO) | F(XSAVEERPTR) |
F(WBNOINVD) | F(AMD_IBPB) | F(AMD_IBRS) | F(AMD_SSBD) | F(VIRT_SSBD) |
F(AMD_SSB_NO) | F(AMD_STIBP) | F(AMD_STIBP_ALWAYS_ON) |
F(AMD_PSFD)
);
/*
* AMD has separate bits for each SPEC_CTRL bit.
* arch/x86/kernel/cpu/bugs.c is kind enough to
* record that in cpufeatures so use them.
*/
if (boot_cpu_has(X86_FEATURE_IBPB))
kvm_cpu_cap_set(X86_FEATURE_AMD_IBPB);
if (boot_cpu_has(X86_FEATURE_IBRS))
kvm_cpu_cap_set(X86_FEATURE_AMD_IBRS);
if (boot_cpu_has(X86_FEATURE_STIBP))
kvm_cpu_cap_set(X86_FEATURE_AMD_STIBP);
if (boot_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD))
kvm_cpu_cap_set(X86_FEATURE_AMD_SSBD);
if (!boot_cpu_has_bug(X86_BUG_SPEC_STORE_BYPASS))
kvm_cpu_cap_set(X86_FEATURE_AMD_SSB_NO);
/*
* The preference is to use SPEC CTRL MSR instead of the
* VIRT_SPEC MSR.
*/
if (boot_cpu_has(X86_FEATURE_LS_CFG_SSBD) &&
!boot_cpu_has(X86_FEATURE_AMD_SSBD))
kvm_cpu_cap_set(X86_FEATURE_VIRT_SSBD);
/*
* Hide all SVM features by default, SVM will set the cap bits for
* features it emulates and/or exposes for L1.
*/
kvm_cpu_cap_mask(CPUID_8000_000A_EDX, 0);
kvm_cpu_cap_mask(CPUID_8000_001F_EAX,
0 /* SME */ | F(SEV) | 0 /* VM_PAGE_FLUSH */ | F(SEV_ES) |
F(SME_COHERENT));
kvm_cpu_cap_mask(CPUID_8000_0021_EAX,
F(NO_NESTED_DATA_BP) | F(LFENCE_RDTSC) | 0 /* SmmPgCfgLock */ |
F(NULL_SEL_CLR_BASE) | F(AUTOIBRS) | 0 /* PrefetchCtlMsr */ |
F(WRMSR_XX_BASE_NS)
);
kvm_cpu_cap_check_and_set(X86_FEATURE_SBPB);
kvm_cpu_cap_check_and_set(X86_FEATURE_IBPB_BRTYPE);
kvm_cpu_cap_check_and_set(X86_FEATURE_SRSO_NO);
kvm_cpu_cap_init_kvm_defined(CPUID_8000_0022_EAX,
F(PERFMON_V2)
);
/*
* Synthesize "LFENCE is serializing" into the AMD-defined entry in
* KVM's supported CPUID if the feature is reported as supported by the
* kernel. LFENCE_RDTSC was a Linux-defined synthetic feature long
* before AMD joined the bandwagon, e.g. LFENCE is serializing on most
* CPUs that support SSE2. On CPUs that don't support AMD's leaf,
* kvm_cpu_cap_mask() will unfortunately drop the flag due to ANDing
* the mask with the raw host CPUID, and reporting support in AMD's
* leaf can make it easier for userspace to detect the feature.
*/
if (cpu_feature_enabled(X86_FEATURE_LFENCE_RDTSC))
kvm_cpu_cap_set(X86_FEATURE_LFENCE_RDTSC);
if (!static_cpu_has_bug(X86_BUG_NULL_SEG))
kvm_cpu_cap_set(X86_FEATURE_NULL_SEL_CLR_BASE);
kvm_cpu_cap_set(X86_FEATURE_NO_SMM_CTL_MSR);
kvm_cpu_cap_mask(CPUID_C000_0001_EDX,
F(XSTORE) | F(XSTORE_EN) | F(XCRYPT) | F(XCRYPT_EN) |
F(ACE2) | F(ACE2_EN) | F(PHE) | F(PHE_EN) |
F(PMM) | F(PMM_EN)
);
/*
* Hide RDTSCP and RDPID if either feature is reported as supported but
* probing MSR_TSC_AUX failed. This is purely a sanity check and
* should never happen, but the guest will likely crash if RDTSCP or
* RDPID is misreported, and KVM has botched MSR_TSC_AUX emulation in
* the past. For example, the sanity check may fire if this instance of
* KVM is running as L1 on top of an older, broken KVM.
*/
if (WARN_ON((kvm_cpu_cap_has(X86_FEATURE_RDTSCP) ||
kvm_cpu_cap_has(X86_FEATURE_RDPID)) &&
!kvm_is_supported_user_return_msr(MSR_TSC_AUX))) {
kvm_cpu_cap_clear(X86_FEATURE_RDTSCP);
kvm_cpu_cap_clear(X86_FEATURE_RDPID);
}
}
EXPORT_SYMBOL_GPL(kvm_set_cpu_caps);
struct kvm_cpuid_array {
struct kvm_cpuid_entry2 *entries;
int maxnent;
int nent;
};
static struct kvm_cpuid_entry2 *get_next_cpuid(struct kvm_cpuid_array *array)
{
if (array->nent >= array->maxnent)
return NULL;
return &array->entries[array->nent++];
}
static struct kvm_cpuid_entry2 *do_host_cpuid(struct kvm_cpuid_array *array,
u32 function, u32 index)
{
struct kvm_cpuid_entry2 *entry = get_next_cpuid(array);
if (!entry)
return NULL;
memset(entry, 0, sizeof(*entry));
entry->function = function;
entry->index = index;
switch (function & 0xC0000000) {
case 0x40000000:
/* Hypervisor leaves are always synthesized by __do_cpuid_func. */
return entry;
case 0x80000000:
/*
* 0x80000021 is sometimes synthesized by __do_cpuid_func, which
* would result in out-of-bounds calls to do_host_cpuid.
*/
{
static int max_cpuid_80000000;
if (!READ_ONCE(max_cpuid_80000000))
WRITE_ONCE(max_cpuid_80000000, cpuid_eax(0x80000000));
if (function > READ_ONCE(max_cpuid_80000000))
return entry;
}
break;
default:
break;
}
cpuid_count(entry->function, entry->index,
&entry->eax, &entry->ebx, &entry->ecx, &entry->edx);
if (cpuid_function_is_indexed(function))
entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
return entry;
}
static int __do_cpuid_func_emulated(struct kvm_cpuid_array *array, u32 func)
{
struct kvm_cpuid_entry2 *entry;
if (array->nent >= array->maxnent)
return -E2BIG;
entry = &array->entries[array->nent];
entry->function = func;
entry->index = 0;
entry->flags = 0;
switch (func) {
case 0:
entry->eax = 7;
++array->nent;
break;
case 1:
entry->ecx = F(MOVBE);
++array->nent;
break;
case 7:
entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
entry->eax = 0;
if (kvm_cpu_cap_has(X86_FEATURE_RDTSCP))
entry->ecx = F(RDPID);
++array->nent;
break;
default:
break;
}
return 0;
}
static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
{
struct kvm_cpuid_entry2 *entry;
int r, i, max_idx;
/* all calls to cpuid_count() should be made on the same cpu */
get_cpu();
r = -E2BIG;
entry = do_host_cpuid(array, function, 0);
if (!entry)
goto out;
switch (function) {
case 0:
/* Limited to the highest leaf implemented in KVM. */
entry->eax = min(entry->eax, 0x1fU);
break;
case 1:
cpuid_entry_override(entry, CPUID_1_EDX);
cpuid_entry_override(entry, CPUID_1_ECX);
break;
case 2:
/*
* On ancient CPUs, function 2 entries are STATEFUL. That is,
* CPUID(function=2, index=0) may return different results each
* time, with the least-significant byte in EAX enumerating the
* number of times software should do CPUID(2, 0).
*
* Modern CPUs, i.e. every CPU KVM has *ever* run on are less
* idiotic. Intel's SDM states that EAX & 0xff "will always
* return 01H. Software should ignore this value and not
* interpret it as an informational descriptor", while AMD's
* APM states that CPUID(2) is reserved.
*
* WARN if a frankenstein CPU that supports virtualization and
* a stateful CPUID.0x2 is encountered.
*/
WARN_ON_ONCE((entry->eax & 0xff) > 1);
break;
/* functions 4 and 0x8000001d have additional index. */
case 4:
case 0x8000001d:
/*
* Read entries until the cache type in the previous entry is
* zero, i.e. indicates an invalid entry.
*/
for (i = 1; entry->eax & 0x1f; ++i) {
entry = do_host_cpuid(array, function, i);
if (!entry)
goto out;
}
break;
case 6: /* Thermal management */
entry->eax = 0x4; /* allow ARAT */
entry->ebx = 0;
entry->ecx = 0;
entry->edx = 0;
break;
/* function 7 has additional index. */
case 7:
max_idx = entry->eax = min(entry->eax, 2u);
cpuid_entry_override(entry, CPUID_7_0_EBX);
cpuid_entry_override(entry, CPUID_7_ECX);
cpuid_entry_override(entry, CPUID_7_EDX);
/* KVM only supports up to 0x7.2, capped above via min(). */
if (max_idx >= 1) {
entry = do_host_cpuid(array, function, 1);
if (!entry)
goto out;
cpuid_entry_override(entry, CPUID_7_1_EAX);
cpuid_entry_override(entry, CPUID_7_1_EDX);
entry->ebx = 0;
entry->ecx = 0;
}
if (max_idx >= 2) {
entry = do_host_cpuid(array, function, 2);
if (!entry)
goto out;
cpuid_entry_override(entry, CPUID_7_2_EDX);
entry->ecx = 0;
entry->ebx = 0;
entry->eax = 0;
}
break;
case 0xa: { /* Architectural Performance Monitoring */
union cpuid10_eax eax;
union cpuid10_edx edx;
if (!enable_pmu || !static_cpu_has(X86_FEATURE_ARCH_PERFMON)) {
entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
break;
}
eax.split.version_id = kvm_pmu_cap.version;
eax.split.num_counters = kvm_pmu_cap.num_counters_gp;
eax.split.bit_width = kvm_pmu_cap.bit_width_gp;
eax.split.mask_length = kvm_pmu_cap.events_mask_len;
edx.split.num_counters_fixed = kvm_pmu_cap.num_counters_fixed;
edx.split.bit_width_fixed = kvm_pmu_cap.bit_width_fixed;
if (kvm_pmu_cap.version)
edx.split.anythread_deprecated = 1;
edx.split.reserved1 = 0;
edx.split.reserved2 = 0;
entry->eax = eax.full;
entry->ebx = kvm_pmu_cap.events_mask;
entry->ecx = 0;
entry->edx = edx.full;
break;
}
case 0x1f:
case 0xb:
/*
* No topology; a valid topology is indicated by the presence
* of subleaf 1.
*/
entry->eax = entry->ebx = entry->ecx = 0;
break;
case 0xd: {
u64 permitted_xcr0 = kvm_get_filtered_xcr0();
u64 permitted_xss = kvm_caps.supported_xss;
entry->eax &= permitted_xcr0;
entry->ebx = xstate_required_size(permitted_xcr0, false);
entry->ecx = entry->ebx;
entry->edx &= permitted_xcr0 >> 32;
if (!permitted_xcr0)
break;
entry = do_host_cpuid(array, function, 1);
if (!entry)
goto out;
cpuid_entry_override(entry, CPUID_D_1_EAX);
if (entry->eax & (F(XSAVES)|F(XSAVEC)))
entry->ebx = xstate_required_size(permitted_xcr0 | permitted_xss,
true);
else {
WARN_ON_ONCE(permitted_xss != 0);
entry->ebx = 0;
}
entry->ecx &= permitted_xss;
entry->edx &= permitted_xss >> 32;
for (i = 2; i < 64; ++i) {
bool s_state;
if (permitted_xcr0 & BIT_ULL(i))
s_state = false;
else if (permitted_xss & BIT_ULL(i))
s_state = true;
else
continue;
entry = do_host_cpuid(array, function, i);
if (!entry)
goto out;
/*
* The supported check above should have filtered out
* invalid sub-leafs. Only valid sub-leafs should
* reach this point, and they should have a non-zero
* save state size. Furthermore, check whether the
* processor agrees with permitted_xcr0/permitted_xss
* on whether this is an XCR0- or IA32_XSS-managed area.
*/
if (WARN_ON_ONCE(!entry->eax || (entry->ecx & 0x1) != s_state)) {
--array->nent;
continue;
}
if (!kvm_cpu_cap_has(X86_FEATURE_XFD))
entry->ecx &= ~BIT_ULL(2);
entry->edx = 0;
}
break;
}
case 0x12:
/* Intel SGX */
if (!kvm_cpu_cap_has(X86_FEATURE_SGX)) {
entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
break;
}
/*
* Index 0: Sub-features, MISCSELECT (a.k.a extended features)
* and max enclave sizes. The SGX sub-features and MISCSELECT
* are restricted by kernel and KVM capabilities (like most
* feature flags), while enclave size is unrestricted.
*/
cpuid_entry_override(entry, CPUID_12_EAX);
entry->ebx &= SGX_MISC_EXINFO;
entry = do_host_cpuid(array, function, 1);
if (!entry)
goto out;
/*
* Index 1: SECS.ATTRIBUTES. ATTRIBUTES are restricted a la
* feature flags. Advertise all supported flags, including
* privileged attributes that require explicit opt-in from
* userspace. ATTRIBUTES.XFRM is not adjusted as userspace is
* expected to derive it from supported XCR0.
*/
entry->eax &= SGX_ATTR_PRIV_MASK | SGX_ATTR_UNPRIV_MASK;
entry->ebx &= 0;
break;
/* Intel PT */
case 0x14:
if (!kvm_cpu_cap_has(X86_FEATURE_INTEL_PT)) {
entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
break;
}
for (i = 1, max_idx = entry->eax; i <= max_idx; ++i) {
if (!do_host_cpuid(array, function, i))
goto out;
}
break;
/* Intel AMX TILE */
case 0x1d:
if (!kvm_cpu_cap_has(X86_FEATURE_AMX_TILE)) {
entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
break;
}
for (i = 1, max_idx = entry->eax; i <= max_idx; ++i) {
if (!do_host_cpuid(array, function, i))
goto out;
}
break;
case 0x1e: /* TMUL information */
if (!kvm_cpu_cap_has(X86_FEATURE_AMX_TILE)) {
entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
break;
}
break;
case KVM_CPUID_SIGNATURE: {
const u32 *sigptr = (const u32 *)KVM_SIGNATURE;
entry->eax = KVM_CPUID_FEATURES;
entry->ebx = sigptr[0];
entry->ecx = sigptr[1];
entry->edx = sigptr[2];
break;
}
case KVM_CPUID_FEATURES:
entry->eax = (1 << KVM_FEATURE_CLOCKSOURCE) |
(1 << KVM_FEATURE_NOP_IO_DELAY) |
(1 << KVM_FEATURE_CLOCKSOURCE2) |
(1 << KVM_FEATURE_ASYNC_PF) |
(1 << KVM_FEATURE_PV_EOI) |
(1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT) |
(1 << KVM_FEATURE_PV_UNHALT) |
(1 << KVM_FEATURE_PV_TLB_FLUSH) |
(1 << KVM_FEATURE_ASYNC_PF_VMEXIT) |
(1 << KVM_FEATURE_PV_SEND_IPI) |
(1 << KVM_FEATURE_POLL_CONTROL) |
(1 << KVM_FEATURE_PV_SCHED_YIELD) |
(1 << KVM_FEATURE_ASYNC_PF_INT);
if (sched_info_on())
entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);
entry->ebx = 0;
entry->ecx = 0;
entry->edx = 0;
break;
case 0x80000000:
entry->eax = min(entry->eax, 0x80000022);
/*
* Serializing LFENCE is reported in a multitude of ways, and
* NullSegClearsBase is not reported in CPUID on Zen2; help
* userspace by providing the CPUID leaf ourselves.
*
* However, only do it if the host has CPUID leaf 0x8000001d.
* QEMU thinks that it can query the host blindly for that
* CPUID leaf if KVM reports that it supports 0x8000001d or
* above. The processor merrily returns values from the
* highest Intel leaf which QEMU tries to use as the guest's
* 0x8000001d. Even worse, this can result in an infinite
* loop if said highest leaf has no subleaves indexed by ECX.
*/
if (entry->eax >= 0x8000001d &&
(static_cpu_has(X86_FEATURE_LFENCE_RDTSC)
|| !static_cpu_has_bug(X86_BUG_NULL_SEG)))
entry->eax = max(entry->eax, 0x80000021);
break;
case 0x80000001:
entry->ebx &= ~GENMASK(27, 16);
cpuid_entry_override(entry, CPUID_8000_0001_EDX);
cpuid_entry_override(entry, CPUID_8000_0001_ECX);
break;
case 0x80000005:
/* Pass host L1 cache and TLB info. */
break;
case 0x80000006:
/* Drop reserved bits, pass host L2 cache and TLB info. */
entry->edx &= ~GENMASK(17, 16);
break;
case 0x80000007: /* Advanced power management */
cpuid_entry_override(entry, CPUID_8000_0007_EDX);
/* mask against host */
entry->edx &= boot_cpu_data.x86_power;
entry->eax = entry->ebx = entry->ecx = 0;
break;
case 0x80000008: {
unsigned g_phys_as = (entry->eax >> 16) & 0xff;
unsigned virt_as = max((entry->eax >> 8) & 0xff, 48U);
unsigned phys_as = entry->eax & 0xff;
/*
* If TDP (NPT) is disabled use the adjusted host MAXPHYADDR as
* the guest operates in the same PA space as the host, i.e.
* reductions in MAXPHYADDR for memory encryption affect shadow
* paging, too.
*
* If TDP is enabled but an explicit guest MAXPHYADDR is not
* provided, use the raw bare metal MAXPHYADDR as reductions to
* the HPAs do not affect GPAs.
*/
if (!tdp_enabled)
g_phys_as = boot_cpu_data.x86_phys_bits;
else if (!g_phys_as)
g_phys_as = phys_as;
entry->eax = g_phys_as | (virt_as << 8);
entry->ecx &= ~(GENMASK(31, 16) | GENMASK(11, 8));
entry->edx = 0;
cpuid_entry_override(entry, CPUID_8000_0008_EBX);
break;
}
case 0x8000000A:
if (!kvm_cpu_cap_has(X86_FEATURE_SVM)) {
entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
break;
}
entry->eax = 1; /* SVM revision 1 */
entry->ebx = 8; /* Lets support 8 ASIDs in case we add proper
ASID emulation to nested SVM */
entry->ecx = 0; /* Reserved */
cpuid_entry_override(entry, CPUID_8000_000A_EDX);
break;
case 0x80000019:
entry->ecx = entry->edx = 0;
break;
case 0x8000001a:
entry->eax &= GENMASK(2, 0);
entry->ebx = entry->ecx = entry->edx = 0;
break;
case 0x8000001e:
/* Do not return host topology information. */
entry->eax = entry->ebx = entry->ecx = 0;
entry->edx = 0; /* reserved */
break;
case 0x8000001F:
if (!kvm_cpu_cap_has(X86_FEATURE_SEV)) {
entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
} else {
cpuid_entry_override(entry, CPUID_8000_001F_EAX);
/* Clear NumVMPL since KVM does not support VMPL. */
entry->ebx &= ~GENMASK(31, 12);
/*
* Enumerate '0' for "PA bits reduction", the adjusted
* MAXPHYADDR is enumerated directly (see 0x80000008).
*/
entry->ebx &= ~GENMASK(11, 6);
}
break;
case 0x80000020:
entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
break;
case 0x80000021:
entry->ebx = entry->ecx = entry->edx = 0;
cpuid_entry_override(entry, CPUID_8000_0021_EAX);
break;
/* AMD Extended Performance Monitoring and Debug */
case 0x80000022: {
union cpuid_0x80000022_ebx ebx;
entry->ecx = entry->edx = 0;
if (!enable_pmu || !kvm_cpu_cap_has(X86_FEATURE_PERFMON_V2)) {
entry->eax = entry->ebx;
break;
}
cpuid_entry_override(entry, CPUID_8000_0022_EAX);
if (kvm_cpu_cap_has(X86_FEATURE_PERFMON_V2))
ebx.split.num_core_pmc = kvm_pmu_cap.num_counters_gp;
else if (kvm_cpu_cap_has(X86_FEATURE_PERFCTR_CORE))
ebx.split.num_core_pmc = AMD64_NUM_COUNTERS_CORE;
else
ebx.split.num_core_pmc = AMD64_NUM_COUNTERS;
entry->ebx = ebx.full;
break;
}
/*Add support for Centaur's CPUID instruction*/
case 0xC0000000:
/*Just support up to 0xC0000004 now*/
entry->eax = min(entry->eax, 0xC0000004);
break;
case 0xC0000001:
cpuid_entry_override(entry, CPUID_C000_0001_EDX);
break;
case 3: /* Processor serial number */
case 5: /* MONITOR/MWAIT */
case 0xC0000002:
case 0xC0000003:
case 0xC0000004:
default:
entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
break;
}
r = 0;
out:
put_cpu();
return r;
}
static int do_cpuid_func(struct kvm_cpuid_array *array, u32 func,
unsigned int type)
{
if (type == KVM_GET_EMULATED_CPUID)
return __do_cpuid_func_emulated(array, func);
return __do_cpuid_func(array, func);
}
#define CENTAUR_CPUID_SIGNATURE 0xC0000000
static int get_cpuid_func(struct kvm_cpuid_array *array, u32 func,
unsigned int type)
{
u32 limit;
int r;
if (func == CENTAUR_CPUID_SIGNATURE &&
boot_cpu_data.x86_vendor != X86_VENDOR_CENTAUR)
return 0;
r = do_cpuid_func(array, func, type);
if (r)
return r;
limit = array->entries[array->nent - 1].eax;
for (func = func + 1; func <= limit; ++func) {
r = do_cpuid_func(array, func, type);
if (r)
break;
}
return r;
}
static bool sanity_check_entries(struct kvm_cpuid_entry2 __user *entries,
__u32 num_entries, unsigned int ioctl_type)
{
int i;
__u32 pad[3];
if (ioctl_type != KVM_GET_EMULATED_CPUID)
return false;
/*
* We want to make sure that ->padding is being passed clean from
* userspace in case we want to use it for something in the future.
*
* Sadly, this wasn't enforced for KVM_GET_SUPPORTED_CPUID and so we
* have to give ourselves satisfied only with the emulated side. /me
* sheds a tear.
*/
for (i = 0; i < num_entries; i++) {
if (copy_from_user(pad, entries[i].padding, sizeof(pad)))
return true;
if (pad[0] || pad[1] || pad[2])
return true;
}
return false;
}
int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,
struct kvm_cpuid_entry2 __user *entries,
unsigned int type)
{
static const u32 funcs[] = {
0, 0x80000000, CENTAUR_CPUID_SIGNATURE, KVM_CPUID_SIGNATURE,
};
struct kvm_cpuid_array array = {
.nent = 0,
};
int r, i;
if (cpuid->nent < 1)
return -E2BIG;
if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
cpuid->nent = KVM_MAX_CPUID_ENTRIES;
if (sanity_check_entries(entries, cpuid->nent, type))
return -EINVAL;
array.entries = kvcalloc(cpuid->nent, sizeof(struct kvm_cpuid_entry2), GFP_KERNEL);
if (!array.entries)
return -ENOMEM;
array.maxnent = cpuid->nent;
for (i = 0; i < ARRAY_SIZE(funcs); i++) {
r = get_cpuid_func(&array, funcs[i], type);
if (r)
goto out_free;
}
cpuid->nent = array.nent;
if (copy_to_user(entries, array.entries,
array.nent * sizeof(struct kvm_cpuid_entry2)))
r = -EFAULT;
out_free:
kvfree(array.entries);
return r;
}
struct kvm_cpuid_entry2 *kvm_find_cpuid_entry_index(struct kvm_vcpu *vcpu,
u32 function, u32 index)
{
return cpuid_entry2_find(vcpu->arch.cpuid_entries, vcpu->arch.cpuid_nent,
function, index);
}
EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry_index);
struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
u32 function)
{
return cpuid_entry2_find(vcpu->arch.cpuid_entries, vcpu->arch.cpuid_nent,
function, KVM_CPUID_INDEX_NOT_SIGNIFICANT);
}
EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry);
/*
* Intel CPUID semantics treats any query for an out-of-range leaf as if the
* highest basic leaf (i.e. CPUID.0H:EAX) were requested. AMD CPUID semantics
* returns all zeroes for any undefined leaf, whether or not the leaf is in
* range. Centaur/VIA follows Intel semantics.
*
* A leaf is considered out-of-range if its function is higher than the maximum
* supported leaf of its associated class or if its associated class does not
* exist.
*
* There are three primary classes to be considered, with their respective
* ranges described as "<base> - <top>[,<base2> - <top2>] inclusive. A primary
* class exists if a guest CPUID entry for its <base> leaf exists. For a given
* class, CPUID.<base>.EAX contains the max supported leaf for the class.
*
* - Basic: 0x00000000 - 0x3fffffff, 0x50000000 - 0x7fffffff
* - Hypervisor: 0x40000000 - 0x4fffffff
* - Extended: 0x80000000 - 0xbfffffff
* - Centaur: 0xc0000000 - 0xcfffffff
*
* The Hypervisor class is further subdivided into sub-classes that each act as
* their own independent class associated with a 0x100 byte range. E.g. if Qemu
* is advertising support for both HyperV and KVM, the resulting Hypervisor
* CPUID sub-classes are:
*
* - HyperV: 0x40000000 - 0x400000ff
* - KVM: 0x40000100 - 0x400001ff
*/
static struct kvm_cpuid_entry2 *
get_out_of_range_cpuid_entry(struct kvm_vcpu *vcpu, u32 *fn_ptr, u32 index)
{
struct kvm_cpuid_entry2 *basic, *class;
u32 function = *fn_ptr;
basic = kvm_find_cpuid_entry(vcpu, 0);
if (!basic)
return NULL;
if (is_guest_vendor_amd(basic->ebx, basic->ecx, basic->edx) ||
is_guest_vendor_hygon(basic->ebx, basic->ecx, basic->edx))
return NULL;
if (function >= 0x40000000 && function <= 0x4fffffff)
class = kvm_find_cpuid_entry(vcpu, function & 0xffffff00);
else if (function >= 0xc0000000)
class = kvm_find_cpuid_entry(vcpu, 0xc0000000);
else
class = kvm_find_cpuid_entry(vcpu, function & 0x80000000);
if (class && function <= class->eax)
return NULL;
/*
* Leaf specific adjustments are also applied when redirecting to the
* max basic entry, e.g. if the max basic leaf is 0xb but there is no
* entry for CPUID.0xb.index (see below), then the output value for EDX
* needs to be pulled from CPUID.0xb.1.
*/
*fn_ptr = basic->eax;
/*
* The class does not exist or the requested function is out of range;
* the effective CPUID entry is the max basic leaf. Note, the index of
* the original requested leaf is observed!
*/
return kvm_find_cpuid_entry_index(vcpu, basic->eax, index);
}
bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx,
u32 *ecx, u32 *edx, bool exact_only)
{
u32 orig_function = *eax, function = *eax, index = *ecx;
struct kvm_cpuid_entry2 *entry;
bool exact, used_max_basic = false;
entry = kvm_find_cpuid_entry_index(vcpu, function, index);
exact = !!entry;
if (!entry && !exact_only) {
entry = get_out_of_range_cpuid_entry(vcpu, &function, index);
used_max_basic = !!entry;
}
if (entry) {
*eax = entry->eax;
*ebx = entry->ebx;
*ecx = entry->ecx;
*edx = entry->edx;
if (function == 7 && index == 0) {
u64 data;
if (!__kvm_get_msr(vcpu, MSR_IA32_TSX_CTRL, &data, true) &&
(data & TSX_CTRL_CPUID_CLEAR))
*ebx &= ~(F(RTM) | F(HLE));
} else if (function == 0x80000007) {
if (kvm_hv_invtsc_suppressed(vcpu))
*edx &= ~SF(CONSTANT_TSC);
}
} else {
*eax = *ebx = *ecx = *edx = 0;
/*
* When leaf 0BH or 1FH is defined, CL is pass-through
* and EDX is always the x2APIC ID, even for undefined
* subleaves. Index 1 will exist iff the leaf is
* implemented, so we pass through CL iff leaf 1
* exists. EDX can be copied from any existing index.
*/
if (function == 0xb || function == 0x1f) {
entry = kvm_find_cpuid_entry_index(vcpu, function, 1);
if (entry) {
*ecx = index & 0xff;
*edx = entry->edx;
}
}
}
trace_kvm_cpuid(orig_function, index, *eax, *ebx, *ecx, *edx, exact,
used_max_basic);
return exact;
}
EXPORT_SYMBOL_GPL(kvm_cpuid);
int kvm_emulate_cpuid(struct kvm_vcpu *vcpu)
{
u32 eax, ebx, ecx, edx;
if (cpuid_fault_enabled(vcpu) && !kvm_require_cpl(vcpu, 0))
return 1;
eax = kvm_rax_read(vcpu);
ecx = kvm_rcx_read(vcpu);
kvm_cpuid(vcpu, &eax, &ebx, &ecx, &edx, false);
kvm_rax_write(vcpu, eax);
kvm_rbx_write(vcpu, ebx);
kvm_rcx_write(vcpu, ecx);
kvm_rdx_write(vcpu, edx);
return kvm_skip_emulated_instruction(vcpu);
}
EXPORT_SYMBOL_GPL(kvm_emulate_cpuid);
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