Wanpeng Li kernellwp@gmail.com writes:

From: Wanpeng Li wanpengli@tencent.com

Analysis from Sean:

| 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.

This should only happen when svm->vmcb->control.next_rip is not set by hardware as skip_emulated_instruction() itself sets 'svm->next_rip' otherwise, right?

Let's get rid of handle_fastpath_set_msr_irqoff() in svm_exit_handlers_fastpath() to have a quick fix.

which in the light of the whole seeries seems to be appropriate, so:

Reviewed-by: Vitaly Kuznetsov vkuznets@redhat.com

Reported-by: Paul K. kronenpj@kronenpj.dyndns.org Suggested-by: Sean Christopherson sean.j.christopherson@intel.com Cc: Paul K. kronenpj@kronenpj.dyndns.org Cc: stable@vger.kernel.org # v5.8-rc1+ Fixes: 404d5d7bff0d (KVM: X86: Introduce more exit_fastpath_completion enum values) Signed-off-by: Wanpeng Li wanpengli@tencent.com

---

arch/x86/kvm/svm/svm.c | 5 ----- 1 file changed, 5 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 19e622a..c61bc3b 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -3349,11 +3349,6 @@ static void svm_cancel_injection(struct kvm_vcpu *vcpu) static fastpath_t svm_exit_handlers_fastpath(struct kvm_vcpu *vcpu) {

• if (!is_guest_mode(vcpu) &&

•    to_svm(vcpu)->vmcb->control.exit_code == SVM_EXIT_MSR &&
  

•    to_svm(vcpu)->vmcb->control.exit_info_1)
  

• return handle_fastpath_set_msr_irqoff(vcpu);
  

• return EXIT_FASTPATH_NONE;

}