2020-09-09 02:57:18

by Wanpeng Li

Subject: [PATCH 3/3] KVM: SVM: Reenable handle_fastpath_set_msr_irqoff() after complete_interrupts()

From: Wanpeng Li <[email protected]>

Moving the call to svm_exit_handlers_fastpath() after svm_complete_interrupts()
since svm_complete_interrupts() consumes rip and reenable the function
handle_fastpath_set_msr_irqoff() call in svm_exit_handlers_fastpath().

Suggested-by: Sean Christopherson <[email protected]>
Cc: Paul K. <[email protected]>
Signed-off-by: Wanpeng Li <[email protected]>
---
arch/x86/kvm/svm/svm.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 74bcf0a..ac819f0 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3347,6 +3347,11 @@ 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;
}

@@ -3495,7 +3500,6 @@ 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);
@@ -3529,6 +3533,7 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
svm_handle_mce(svm);

svm_complete_interrupts(svm);
+ exit_fastpath = svm_exit_handlers_fastpath(vcpu);

vmcb_mark_all_clean(svm->vmcb);
return exit_fastpath;
--
2.7.4

2020-09-09 08:43:40

by Vitaly Kuznetsov

Subject: Re: [PATCH 3/3] KVM: SVM: Reenable handle_fastpath_set_msr_irqoff() after complete_interrupts()

Wanpeng Li <[email protected]> writes:

> From: Wanpeng Li <[email protected]>
>
> Moving the call to svm_exit_handlers_fastpath() after svm_complete_interrupts()
> since svm_complete_interrupts() consumes rip and reenable the function
> handle_fastpath_set_msr_irqoff() call in svm_exit_handlers_fastpath().
>
> Suggested-by: Sean Christopherson <[email protected]>
> Cc: Paul K. <[email protected]>
> Signed-off-by: Wanpeng Li <[email protected]>
> ---
> arch/x86/kvm/svm/svm.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index 74bcf0a..ac819f0 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -3347,6 +3347,11 @@ 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;
> }
>
> @@ -3495,7 +3500,6 @@ 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);
> @@ -3529,6 +3533,7 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
> svm_handle_mce(svm);
>
> svm_complete_interrupts(svm);
> + exit_fastpath = svm_exit_handlers_fastpath(vcpu);
>
> vmcb_mark_all_clean(svm->vmcb);
> return exit_fastpath;

Reviewed-by: Vitaly Kuznetsov <[email protected]>

--
Vitaly