From: Sean Christopherson <seanjc@xxxxxxxxxx> Allow the use of kvm_load_host_xsave_state() with vcpu->arch.guest_state_protected == true. This will allow TDX to reuse kvm_load_host_xsave_state() instead of creating its own version. For consistency, amend kvm_load_guest_xsave_state() also. Ensure that guest state that kvm_load_host_xsave_state() depends upon, such as MSR_IA32_XSS, cannot be changed by user space, if guest_state_protected. [Adrian: wrote commit message] Link: https://lore.kernel.org/r/Z2GiQS_RmYeHU09L@xxxxxxxxxx Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx> --- TD vcpu enter/exit v2: - New patch --- arch/x86/kvm/svm/svm.c | 7 +++++-- arch/x86/kvm/x86.c | 18 +++++++++++------- 2 files changed, 16 insertions(+), 9 deletions(-) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 7640a84e554a..b4bcfe15ad5e 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4253,7 +4253,9 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu, svm_set_dr6(svm, DR6_ACTIVE_LOW); clgi(); - kvm_load_guest_xsave_state(vcpu); + + if (!vcpu->arch.guest_state_protected) + kvm_load_guest_xsave_state(vcpu); kvm_wait_lapic_expire(vcpu); @@ -4282,7 +4284,8 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu, if (unlikely(svm->vmcb->control.exit_code == SVM_EXIT_NMI)) kvm_before_interrupt(vcpu, KVM_HANDLING_NMI); - kvm_load_host_xsave_state(vcpu); + if (!vcpu->arch.guest_state_protected) + kvm_load_host_xsave_state(vcpu); stgi(); /* Any pending NMI will happen here */ diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index bbb6b7f40b3a..5cf9f023fd4b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1169,11 +1169,9 @@ EXPORT_SYMBOL_GPL(kvm_lmsw); void kvm_load_guest_xsave_state(struct kvm_vcpu *vcpu) { - if (vcpu->arch.guest_state_protected) - return; + WARN_ON_ONCE(vcpu->arch.guest_state_protected); if (kvm_is_cr4_bit_set(vcpu, X86_CR4_OSXSAVE)) { - if (vcpu->arch.xcr0 != kvm_host.xcr0) xsetbv(XCR_XFEATURE_ENABLED_MASK, vcpu->arch.xcr0); @@ -1192,13 +1190,11 @@ EXPORT_SYMBOL_GPL(kvm_load_guest_xsave_state); void kvm_load_host_xsave_state(struct kvm_vcpu *vcpu) { - if (vcpu->arch.guest_state_protected) - return; - if (cpu_feature_enabled(X86_FEATURE_PKU) && ((vcpu->arch.xcr0 & XFEATURE_MASK_PKRU) || kvm_is_cr4_bit_set(vcpu, X86_CR4_PKE))) { - vcpu->arch.pkru = rdpkru(); + if (!vcpu->arch.guest_state_protected) + vcpu->arch.pkru = rdpkru(); if (vcpu->arch.pkru != vcpu->arch.host_pkru) wrpkru(vcpu->arch.host_pkru); } @@ -3916,6 +3912,10 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) if (!msr_info->host_initiated && !guest_cpuid_has(vcpu, X86_FEATURE_XSAVES)) return 1; + + if (vcpu->arch.guest_state_protected) + return 1; + /* * KVM supports exposing PT to the guest, but does not support * IA32_XSS[bit 8]. Guests have to use RDMSR/WRMSR rather than @@ -4375,6 +4375,10 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) if (!msr_info->host_initiated && !guest_cpuid_has(vcpu, X86_FEATURE_XSAVES)) return 1; + + if (vcpu->arch.guest_state_protected) + return 1; + msr_info->data = vcpu->arch.ia32_xss; break; case MSR_K7_CLK_CTL: -- 2.43.0
