diff options
| author | Oliver Upton <oupton@google.com> | 2020-10-27 16:10:42 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-11-08 04:41:29 -0500 |
| commit | 01b4f510b9f467abfc781e198e810e1ecffb782e (patch) | |
| tree | 2e0ca3e840a0a8f9b3dc2a52fb1a91256d2412c7 /arch/x86/kvm/cpuid.c | |
| parent | 1930e5ddcead2c23567131e62c86b15efce054be (diff) | |
| download | lwn-01b4f510b9f467abfc781e198e810e1ecffb782e.tar.gz lwn-01b4f510b9f467abfc781e198e810e1ecffb782e.zip | |
kvm: x86: ensure pv_cpuid.features is initialized when enabling cap
Make the paravirtual cpuid enforcement mechanism idempotent to ioctl()
ordering by updating pv_cpuid.features whenever userspace requests the
capability. Extract this update out of kvm_update_cpuid_runtime() into a
new helper function and move its other call site into
kvm_vcpu_after_set_cpuid() where it more likely belongs.
Fixes: 66570e966dd9 ("kvm: x86: only provide PV features if enabled in guest's CPUID")
Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Message-Id: <20201027231044.655110-5-oupton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/cpuid.c')
| -rw-r--r-- | arch/x86/kvm/cpuid.c | 23 |
1 files changed, 16 insertions, 7 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 06a278b3701d..d50041f570e8 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -90,6 +90,20 @@ static int kvm_check_cpuid(struct kvm_cpuid_entry2 *entries, int nent) return 0; } +void kvm_update_pv_runtime(struct kvm_vcpu *vcpu) +{ + struct kvm_cpuid_entry2 *best; + + best = kvm_find_cpuid_entry(vcpu, KVM_CPUID_FEATURES, 0); + + /* + * save the feature bitmap to avoid cpuid lookup for every PV + * operation + */ + if (best) + vcpu->arch.pv_cpuid.features = best->eax; +} + void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu) { struct kvm_cpuid_entry2 *best; @@ -124,13 +138,6 @@ void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu) (best->eax & (1 << KVM_FEATURE_PV_UNHALT))) best->eax &= ~(1 << KVM_FEATURE_PV_UNHALT); - /* - * save the feature bitmap to avoid cpuid lookup for every PV - * operation - */ - if (best) - vcpu->arch.pv_cpuid.features = best->eax; - if (!kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT)) { best = kvm_find_cpuid_entry(vcpu, 0x1, 0); if (best) @@ -162,6 +169,8 @@ static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) vcpu->arch.guest_supported_xcr0 = (best->eax | ((u64)best->edx << 32)) & supported_xcr0; + kvm_update_pv_runtime(vcpu); + vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu); kvm_mmu_reset_context(vcpu); |