diff options
| author | Aaron Lewis <aaronlewis@google.com> | 2019-10-21 16:30:23 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2019-10-22 15:45:59 +0200 |
| commit | 312a1c87798e6b43ff533393167b3cba33645ead (patch) | |
| tree | 5321085e5ad08feffd3a2500fa5231606a55cb5d /arch/x86/kvm/svm.c | |
| parent | 78958563d8023db0c6d03a2fe2a64d79b47b4349 (diff) | |
KVM: SVM: Use wrmsr for switching between guest and host IA32_XSS on AMD
When the guest can execute the XSAVES/XRSTORS instructions, set the
hardware IA32_XSS MSR to guest/host values on VM-entry/VM-exit.
Note that vcpu->arch.ia32_xss is currently guaranteed to be 0 on AMD,
since there is no way to change it.
Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Change-Id: Id51a782462086e6d7a3ab621838e200f1c005afd
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/svm.c')
| -rw-r--r-- | arch/x86/kvm/svm.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index cf224963e7d1..fa29125193fe 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -116,6 +116,8 @@ MODULE_DEVICE_TABLE(x86cpu, svm_cpu_id); static bool erratum_383_found __read_mostly; +static u64 __read_mostly host_xss; + static const u32 host_save_user_msrs[] = { #ifdef CONFIG_X86_64 MSR_STAR, MSR_LSTAR, MSR_CSTAR, MSR_SYSCALL_MASK, MSR_KERNEL_GS_BASE, @@ -1409,6 +1411,9 @@ static __init int svm_hardware_setup(void) pr_info("Virtual GIF supported\n"); } + if (boot_cpu_has(X86_FEATURE_XSAVES)) + rdmsrl(MSR_IA32_XSS, host_xss); + return 0; err: @@ -5598,6 +5603,22 @@ static void svm_cancel_injection(struct kvm_vcpu *vcpu) svm_complete_interrupts(svm); } +static void svm_load_guest_xss(struct kvm_vcpu *vcpu) +{ + if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE) && + vcpu->arch.xsaves_enabled && + vcpu->arch.ia32_xss != host_xss) + wrmsrl(MSR_IA32_XSS, vcpu->arch.ia32_xss); +} + +static void svm_load_host_xss(struct kvm_vcpu *vcpu) +{ + if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE) && + vcpu->arch.xsaves_enabled && + vcpu->arch.ia32_xss != host_xss) + wrmsrl(MSR_IA32_XSS, host_xss); +} + static void svm_vcpu_run(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu); @@ -5637,6 +5658,7 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu) clgi(); kvm_load_guest_xcr0(vcpu); + svm_load_guest_xss(vcpu); if (lapic_in_kernel(vcpu) && vcpu->arch.apic->lapic_timer.timer_advance_ns) @@ -5786,6 +5808,7 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu) if (unlikely(svm->vmcb->control.exit_code == SVM_EXIT_NMI)) kvm_before_interrupt(&svm->vcpu); + svm_load_host_xss(vcpu); kvm_put_guest_xcr0(vcpu); stgi(); |