diff options
| author | Sean Christopherson <seanjc@google.com> | 2025-12-01 17:50:49 -0800 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2025-12-02 08:49:32 -0800 |
| commit | 824d227324dcd328857b70e37b41780f02225729 (patch) | |
| tree | 20d038a06ac110cf210ce3c8873aeed012d24048 | |
| parent | e2b43fb25243d502ad36b07bab9de09f4b76fff9 (diff) | |
KVM: selftests: Add a CPUID testcase for KVM_SET_CPUID2 with runtime updates
Add a CPUID testcase to verify that KVM allows KVM_SET_CPUID2 after (or in
conjunction with) runtime updates. This is a regression test for the bug
introduced by commit 93da6af3ae56 ("KVM: x86: Defer runtime updates of
dynamic CPUID bits until CPUID emulation"), where KVM would incorrectly
reject KVM_SET_CPUID due to a not handling a pending runtime update on the
current CPUID, resulting in a false mismatch between the "old" and "new"
CPUID entries.
Link: https://lore.kernel.org/all/20251128123202.68424a95@imammedo
Link: https://patch.msgid.link/20251202015049.1167490-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
| -rw-r--r-- | tools/testing/selftests/kvm/x86/cpuid_test.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/x86/cpuid_test.c b/tools/testing/selftests/kvm/x86/cpuid_test.c index 7b3fda6842bc..f9ed14996977 100644 --- a/tools/testing/selftests/kvm/x86/cpuid_test.c +++ b/tools/testing/selftests/kvm/x86/cpuid_test.c @@ -155,6 +155,7 @@ struct kvm_cpuid2 *vcpu_alloc_cpuid(struct kvm_vm *vm, vm_vaddr_t *p_gva, struct static void set_cpuid_after_run(struct kvm_vcpu *vcpu) { struct kvm_cpuid_entry2 *ent; + struct kvm_sregs sregs; int rc; u32 eax, ebx, x; @@ -162,6 +163,20 @@ static void set_cpuid_after_run(struct kvm_vcpu *vcpu) rc = __vcpu_set_cpuid(vcpu); TEST_ASSERT(!rc, "Setting unmodified CPUID after KVM_RUN failed: %d", rc); + /* + * Toggle CR4 bits that affect dynamic CPUID feature flags to verify + * setting unmodified CPUID succeeds with runtime CPUID updates. + */ + vcpu_sregs_get(vcpu, &sregs); + if (kvm_cpu_has(X86_FEATURE_XSAVE)) + sregs.cr4 ^= X86_CR4_OSXSAVE; + if (kvm_cpu_has(X86_FEATURE_PKU)) + sregs.cr4 ^= X86_CR4_PKE; + vcpu_sregs_set(vcpu, &sregs); + + rc = __vcpu_set_cpuid(vcpu); + TEST_ASSERT(!rc, "Setting unmodified CPUID after KVM_RUN failed: %d", rc); + /* Changing CPU features is forbidden */ ent = vcpu_get_cpuid_entry(vcpu, 0x7); ebx = ent->ebx; |