Currently we save host state like user-visible host MSRs, and do some initial guest register setup for MSR_TSC_AUX and MSR_AMD64_TSC_RATIO in svm_vcpu_load(). Defer this until just before we enter the guest by moving the handling to kvm_x86_ops.prepare_guest_switch() similarly to how it is done for the VMX implementation.
Additionally, since handling of saving/restoring host user MSRs is the same both with/without SEV-ES enabled, move that handling to common code. Suggested-by: Sean Christopherson <sea...@google.com> Signed-off-by: Michael Roth <michael.r...@amd.com> --- arch/x86/kvm/svm/sev.c | 22 +----------- arch/x86/kvm/svm/svm.c | 76 +++++++++++++++++++++++++++++------------- arch/x86/kvm/svm/svm.h | 5 +-- 3 files changed, 56 insertions(+), 47 deletions(-) diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 87167ef8ca23..874ea309279f 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -2066,11 +2066,10 @@ void sev_es_create_vcpu(struct vcpu_svm *svm) sev_enc_bit)); } -void sev_es_vcpu_load(struct vcpu_svm *svm, int cpu) +void sev_es_prepare_guest_switch(struct vcpu_svm *svm, unsigned int cpu) { struct svm_cpu_data *sd = per_cpu(svm_data, cpu); struct vmcb_save_area *hostsa; - unsigned int i; /* * As an SEV-ES guest, hardware will restore the host state on VMEXIT, @@ -2079,13 +2078,6 @@ void sev_es_vcpu_load(struct vcpu_svm *svm, int cpu) */ vmsave(__sme_page_pa(sd->save_area)); - /* - * Certain MSRs are restored on VMEXIT, only save ones that aren't - * restored. - */ - for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++) - rdmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]); - /* XCR0 is restored on VMEXIT, save the current host value */ hostsa = (struct vmcb_save_area *)(page_address(sd->save_area) + 0x400); hostsa->xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK); @@ -2097,18 +2089,6 @@ void sev_es_vcpu_load(struct vcpu_svm *svm, int cpu) hostsa->xss = host_xss; } -void sev_es_vcpu_put(struct vcpu_svm *svm) -{ - unsigned int i; - - /* - * Certain MSRs are restored on VMEXIT and were saved with vmsave in - * sev_es_vcpu_load() above. Only restore ones that weren't. - */ - for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++) - wrmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]); -} - void sev_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector) { struct vcpu_svm *svm = to_svm(vcpu); diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index ae897aaa4471..0059f1d14b82 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -1361,6 +1361,7 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu) svm->vmsa = page_address(vmsa_page); svm->asid_generation = 0; + svm->guest_state_loaded = false; init_vmcb(svm); svm_init_osvw(vcpu); @@ -1408,23 +1409,30 @@ static void svm_free_vcpu(struct kvm_vcpu *vcpu) __free_pages(virt_to_page(svm->msrpm), MSRPM_ALLOC_ORDER); } -static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu) +static void svm_prepare_guest_switch(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu); - struct svm_cpu_data *sd = per_cpu(svm_data, cpu); - int i; + struct svm_cpu_data *sd = per_cpu(svm_data, vcpu->cpu); + unsigned int i; - if (unlikely(cpu != vcpu->cpu)) { - svm->asid_generation = 0; - vmcb_mark_all_dirty(svm->vmcb); - } + if (svm->guest_state_loaded) + return; + + /* + * Certain MSRs are restored on VMEXIT (sev-es), or vmload of host save + * area (non-sev-es). Save ones that aren't so we can restore them + * individually later. + */ + for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++) + rdmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]); + /* + * Save additional host state that will be restored on VMEXIT (sev-es) + * or subsequent vmload of host save area. + */ if (sev_es_guest(svm->vcpu.kvm)) { - sev_es_vcpu_load(svm, cpu); + sev_es_prepare_guest_switch(svm, vcpu->cpu); } else { - for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++) - rdmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]); - vmsave(__sme_page_pa(sd->save_area)); } @@ -1435,10 +1443,42 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu) wrmsrl(MSR_AMD64_TSC_RATIO, tsc_ratio); } } + /* This assumes that the kernel never uses MSR_TSC_AUX */ if (static_cpu_has(X86_FEATURE_RDTSCP)) wrmsrl(MSR_TSC_AUX, svm->tsc_aux); + svm->guest_state_loaded = true; +} + +static void svm_prepare_host_switch(struct kvm_vcpu *vcpu) +{ + struct vcpu_svm *svm = to_svm(vcpu); + unsigned int i; + + if (!svm->guest_state_loaded) + return; + + /* + * Certain MSRs are restored on VMEXIT (sev-es), or vmload of host save + * area (non-sev-es). Restore the ones that weren't. + */ + for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++) + wrmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]); + + svm->guest_state_loaded = false; +} + +static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu) +{ + struct vcpu_svm *svm = to_svm(vcpu); + struct svm_cpu_data *sd = per_cpu(svm_data, cpu); + + if (unlikely(cpu != vcpu->cpu)) { + svm->asid_generation = 0; + vmcb_mark_all_dirty(svm->vmcb); + } + if (sd->current_vmcb != svm->vmcb) { sd->current_vmcb = svm->vmcb; indirect_branch_prediction_barrier(); @@ -1448,18 +1488,10 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu) static void svm_vcpu_put(struct kvm_vcpu *vcpu) { - struct vcpu_svm *svm = to_svm(vcpu); - int i; - avic_vcpu_put(vcpu); + svm_prepare_host_switch(vcpu); ++vcpu->stat.host_state_reload; - if (sev_es_guest(svm->vcpu.kvm)) { - sev_es_vcpu_put(svm); - } else { - for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++) - wrmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]); - } } static unsigned long svm_get_rflags(struct kvm_vcpu *vcpu) @@ -3614,10 +3646,6 @@ static void svm_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t gva) invlpga(gva, svm->vmcb->control.asid); } -static void svm_prepare_guest_switch(struct kvm_vcpu *vcpu) -{ -} - static inline void sync_cr8_to_lapic(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu); diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 66d83dfefe18..cfc495c71fc1 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -172,6 +172,8 @@ struct vcpu_svm { u64 ghcb_sa_len; bool ghcb_sa_sync; bool ghcb_sa_free; + + bool guest_state_loaded; }; struct svm_cpu_data { @@ -570,9 +572,8 @@ int sev_handle_vmgexit(struct vcpu_svm *svm); int sev_es_string_io(struct vcpu_svm *svm, int size, unsigned int port, int in); void sev_es_init_vmcb(struct vcpu_svm *svm); void sev_es_create_vcpu(struct vcpu_svm *svm); -void sev_es_vcpu_load(struct vcpu_svm *svm, int cpu); -void sev_es_vcpu_put(struct vcpu_svm *svm); void sev_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector); +void sev_es_prepare_guest_switch(struct vcpu_svm *svm, unsigned int cpu); /* vmenter.S */ -- 2.25.1