2020-09-09 02:56:58

by Wanpeng Li

Subject: [PATCH 2/3] KVM: SVM: Move svm_complete_interrupts() into svm_vcpu_run()

From: Wanpeng Li <[email protected]>

Moving svm_complete_interrupts() into svm_vcpu_run() which can align VMX
and SVM with respect to completing interrupts.

Suggested-by: Sean Christopherson <[email protected]>
Cc: Paul K. <[email protected]>
Signed-off-by: Wanpeng Li <[email protected]>
---
arch/x86/kvm/svm/svm.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index c61bc3b..74bcf0a 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;

@@ -3530,6 +3528,8 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
SVM_EXIT_EXCP_BASE + MC_VECTOR))
svm_handle_mce(svm);

+ svm_complete_interrupts(svm);
+
vmcb_mark_all_clean(svm->vmcb);
return exit_fastpath;
}
--
2.7.4

2020-09-09 08:37:29

by Vitaly Kuznetsov

Subject: Re: [PATCH 2/3] KVM: SVM: Move svm_complete_interrupts() into svm_vcpu_run()

Wanpeng Li <[email protected]> writes:

> From: Wanpeng Li <[email protected]>
>
> Moving svm_complete_interrupts() into svm_vcpu_run() which can align VMX
> and SVM with respect to completing interrupts.
>
> Suggested-by: Sean Christopherson <[email protected]>
> Cc: Paul K. <[email protected]>
> Signed-off-by: Wanpeng Li <[email protected]>
> ---
> arch/x86/kvm/svm/svm.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index c61bc3b..74bcf0a 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;
>
> @@ -3530,6 +3528,8 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
> SVM_EXIT_EXCP_BASE + MC_VECTOR))
> svm_handle_mce(svm);
>
> + svm_complete_interrupts(svm);
> +
> vmcb_mark_all_clean(svm->vmcb);
> return exit_fastpath;
> }

This seems to be the right thing to do, however, the amount of code
between kvm_x86_ops.run() and kvm_x86_ops.handle_exit() is non-trivial,
hope it won't blow up in testing...

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

One more thing:

VMX version does

vmx_complete_interrupts(vmx);
if (is_guest_mode(vcpu))
return EXIT_FASTPATH_NONE;

and on SVM we analyze is_guest_mode() inside
svm_exit_handlers_fastpath() - should we also change that for
conformity?

--
Vitaly

2020-09-09 08:49:13

by Wanpeng Li

Subject: Re: [PATCH 2/3] KVM: SVM: Move svm_complete_interrupts() into svm_vcpu_run()

On Wed, 9 Sep 2020 at 16:36, Vitaly Kuznetsov <[email protected]> wrote:
>
> Wanpeng Li <[email protected]> writes:
>
> > From: Wanpeng Li <[email protected]>
> >
> > Moving svm_complete_interrupts() into svm_vcpu_run() which can align VMX
> > and SVM with respect to completing interrupts.
> >
> > Suggested-by: Sean Christopherson <[email protected]>
> > Cc: Paul K. <[email protected]>
> > Signed-off-by: Wanpeng Li <[email protected]>
> > ---
> > arch/x86/kvm/svm/svm.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> > index c61bc3b..74bcf0a 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;
> >
> > @@ -3530,6 +3528,8 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
> > SVM_EXIT_EXCP_BASE + MC_VECTOR))
> > svm_handle_mce(svm);
> >
> > + svm_complete_interrupts(svm);
> > +
> > vmcb_mark_all_clean(svm->vmcb);
> > return exit_fastpath;
> > }
>
> This seems to be the right thing to do, however, the amount of code
> between kvm_x86_ops.run() and kvm_x86_ops.handle_exit() is non-trivial,
> hope it won't blow up in testing...
>
> Reviewed-by: Vitaly Kuznetsov <[email protected]>
>
> One more thing:
>
> VMX version does
>
> vmx_complete_interrupts(vmx);
> if (is_guest_mode(vcpu))
> return EXIT_FASTPATH_NONE;
>
> and on SVM we analyze is_guest_mode() inside
> svm_exit_handlers_fastpath() - should we also change that for
> conformity?

Agreed, will do in v2.

Wanpeng

2020-09-12 06:21:49

by Paolo Bonzini

Subject: Re: [PATCH 2/3] KVM: SVM: Move svm_complete_interrupts() into svm_vcpu_run()

On 09/09/20 10:47, Wanpeng Li wrote:
>> One more thing:
>>
>> VMX version does
>>
>> vmx_complete_interrupts(vmx);
>> if (is_guest_mode(vcpu))
>> return EXIT_FASTPATH_NONE;
>>
>> and on SVM we analyze is_guest_mode() inside
>> svm_exit_handlers_fastpath() - should we also change that for
>> conformity?
>
> Agreed, will do in v2.

Please just send an incremental patch. Thanks!

Paolo

2020-09-14 06:59:40

by Wanpeng Li

Subject: Re: [PATCH 2/3] KVM: SVM: Move svm_complete_interrupts() into svm_vcpu_run()

On Sat, 12 Sep 2020 at 14:20, Paolo Bonzini <[email protected]> wrote:
>
> On 09/09/20 10:47, Wanpeng Li wrote:
> >> One more thing:
> >>
> >> VMX version does
> >>
> >> vmx_complete_interrupts(vmx);
> >> if (is_guest_mode(vcpu))
> >> return EXIT_FASTPATH_NONE;
> >>
> >> and on SVM we analyze is_guest_mode() inside
> >> svm_exit_handlers_fastpath() - should we also change that for
> >> conformity?
> >
> > Agreed, will do in v2.
>
> Please just send an incremental patch. Thanks!

Just sent out a patch to do it. :)

Wanpeng