KVM: x86: simplify handling of PKRU
Move it to struct kvm_arch_vcpu, replacing guest_pkru_valid with a
simple comparison against the host value of the register. The write of
PKRU in addition can be skipped if the guest has not enabled the feature.
Once we do this, we need not test OSPKE in the host anymore, because
guest_CR4.PKE=1 implies host_CR4.PKE=1.
The static PKU test is kept to elide the code on older CPUs.
Suggested-by: Yang Zhang <zy107165@alibaba-inc.com>
Fixes: 1be0e61c1f255faaeab04a390e00c8b9b9042870
Cc: stable@vger.kernel.org
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 9b21b12..c6ef294 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -636,8 +636,6 @@ struct vcpu_vmx {
u64 current_tsc_ratio;
- bool guest_pkru_valid;
- u32 guest_pkru;
u32 host_pkru;
/*
@@ -2383,11 +2381,6 @@ static void vmx_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags)
to_vmx(vcpu)->emulation_required = emulation_required(vcpu);
}
-static u32 vmx_get_pkru(struct kvm_vcpu *vcpu)
-{
- return to_vmx(vcpu)->guest_pkru;
-}
-
static u32 vmx_get_interrupt_shadow(struct kvm_vcpu *vcpu)
{
u32 interruptibility = vmcs_read32(GUEST_INTERRUPTIBILITY_INFO);
@@ -9020,8 +9013,10 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
vmx_set_interrupt_shadow(vcpu, 0);
- if (vmx->guest_pkru_valid)
- __write_pkru(vmx->guest_pkru);
+ if (static_cpu_has(X86_FEATURE_PKU) &&
+ kvm_read_cr4_bits(vcpu, X86_CR4_PKE) &&
+ vcpu->arch.pkru != vmx->host_pkru)
+ __write_pkru(vcpu->arch.pkru);
atomic_switch_perf_msrs(vmx);
debugctlmsr = get_debugctlmsr();
@@ -9169,13 +9164,11 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
* back on host, so it is safe to read guest PKRU from current
* XSAVE.
*/
- if (boot_cpu_has(X86_FEATURE_OSPKE)) {
- vmx->guest_pkru = __read_pkru();
- if (vmx->guest_pkru != vmx->host_pkru) {
- vmx->guest_pkru_valid = true;
+ if (static_cpu_has(X86_FEATURE_PKU) &&
+ kvm_read_cr4_bits(vcpu, X86_CR4_PKE)) {
+ vcpu->arch.pkru = __read_pkru();
+ if (vcpu->arch.pkru != vmx->host_pkru)
__write_pkru(vmx->host_pkru);
- } else
- vmx->guest_pkru_valid = false;
}
/*
@@ -11682,8 +11675,6 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = {
.get_rflags = vmx_get_rflags,
.set_rflags = vmx_set_rflags,
- .get_pkru = vmx_get_pkru,
-
.tlb_flush = vmx_flush_tlb,
.run = vmx_vcpu_run,