Messages in this thread | | | From | Vitaly Kuznetsov <> | Subject | Re: [PATCH 1/3] KVM: SVM: Get rid of handle_fastpath_set_msr_irqoff() | Date | Wed, 09 Sep 2020 10:23:20 +0200 |
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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; > }
-- Vitaly
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