From e42c68281b444f9a20d72a062f8c6fd0d31e4de8 Mon Sep 17 00:00:00 2001 From: Wanpeng Li Date: Sat, 12 Sep 2020 02:16:39 -0400 Subject: [PATCH] KVM: SVM: avoid emulation with stale next_rip svm->next_rip is reset in svm_vcpu_run() only after calling svm_exit_handlers_fastpath(), which will cause SVM's skip_emulated_instruction() to write a stale RIP. We can move svm_exit_handlers_fastpath towards the end of svm_vcpu_run(). To align VMX with SVM, keep svm_complete_interrupts() close as well. Suggested-by: Sean Christopherson Cc: Paul K. Reviewed-by: Vitaly Kuznetsov Signed-off-by: Wanpeng Li [Also move vmcb_mark_all_clean before any possible write to the VMCB. - Paolo] --- arch/x86/kvm/svm/svm.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 03dd7bac80348..8ba4a32843fa3 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -2938,8 +2938,6 @@ static int handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath) if (npt_enabled) vcpu->arch.cr3 = svm->vmcb->save.cr3; - svm_complete_interrupts(svm); - if (is_guest_mode(vcpu)) { int vmexit; @@ -3504,7 +3502,6 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu) stgi(); /* Any pending NMI will happen here */ - exit_fastpath = svm_exit_handlers_fastpath(vcpu); if (unlikely(svm->vmcb->control.exit_code == SVM_EXIT_NMI)) kvm_after_interrupt(&svm->vcpu); @@ -3518,6 +3515,7 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu) } svm->vmcb->control.tlb_ctl = TLB_CONTROL_DO_NOTHING; + vmcb_mark_all_clean(svm->vmcb); /* if exit due to PF check for async PF */ if (svm->vmcb->control.exit_code == SVM_EXIT_EXCP_BASE + PF_VECTOR) @@ -3537,7 +3535,8 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu) SVM_EXIT_EXCP_BASE + MC_VECTOR)) svm_handle_mce(svm); - vmcb_mark_all_clean(svm->vmcb); + svm_complete_interrupts(svm); + exit_fastpath = svm_exit_handlers_fastpath(vcpu); return exit_fastpath; } -- GitLab