* [PATCH] KVM: VMX: blocked-by-sti must not defer NMI injections
@ 2010-05-11 13:16 Jan Kiszka
2010-05-11 13:46 ` Gleb Natapov
2010-05-12 20:05 ` Marcelo Tosatti
0 siblings, 2 replies; 3+ messages in thread
From: Jan Kiszka @ 2010-05-11 13:16 UTC (permalink / raw)
To: Avi Kivity, Marcelo Tosatti; +Cc: kvm, Gleb Natapov
As the processor may not consider GUEST_INTR_STATE_STI as a reason for
blocking NMI, it could return immediately with EXIT_REASON_NMI_WINDOW
when we asked for it. But as we consider this state as NMI-blocking, we
can run into an endless loop.
Resolve this by allowing NMI injection if just GUEST_INTR_STATE_STI is
active (originally suggested by Gleb). Intel confirmed that this is
safe, the processor will never complain about NMI injection in this
state.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
KVM-Stable-Tag
---
arch/x86/kvm/vmx.c | 3 +--
1 files changed, 1 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 777e00d..fa3959b 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2824,8 +2824,7 @@ static int vmx_nmi_allowed(struct kvm_vcpu *vcpu)
return 0;
return !(vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) &
- (GUEST_INTR_STATE_STI | GUEST_INTR_STATE_MOV_SS |
- GUEST_INTR_STATE_NMI));
+ (GUEST_INTR_STATE_MOV_SS | GUEST_INTR_STATE_NMI));
}
static bool vmx_get_nmi_mask(struct kvm_vcpu *vcpu)
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] KVM: VMX: blocked-by-sti must not defer NMI injections
2010-05-11 13:16 [PATCH] KVM: VMX: blocked-by-sti must not defer NMI injections Jan Kiszka
@ 2010-05-11 13:46 ` Gleb Natapov
2010-05-12 20:05 ` Marcelo Tosatti
1 sibling, 0 replies; 3+ messages in thread
From: Gleb Natapov @ 2010-05-11 13:46 UTC (permalink / raw)
To: Jan Kiszka; +Cc: Avi Kivity, Marcelo Tosatti, kvm
On Tue, May 11, 2010 at 03:16:46PM +0200, Jan Kiszka wrote:
> As the processor may not consider GUEST_INTR_STATE_STI as a reason for
> blocking NMI, it could return immediately with EXIT_REASON_NMI_WINDOW
> when we asked for it. But as we consider this state as NMI-blocking, we
> can run into an endless loop.
>
> Resolve this by allowing NMI injection if just GUEST_INTR_STATE_STI is
> active (originally suggested by Gleb). Intel confirmed that this is
> safe, the processor will never complain about NMI injection in this
> state.
>
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Acked-by: Gleb Natapov<gleb@redhat.com>
> KVM-Stable-Tag
> ---
> arch/x86/kvm/vmx.c | 3 +--
> 1 files changed, 1 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 777e00d..fa3959b 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -2824,8 +2824,7 @@ static int vmx_nmi_allowed(struct kvm_vcpu *vcpu)
> return 0;
>
> return !(vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) &
> - (GUEST_INTR_STATE_STI | GUEST_INTR_STATE_MOV_SS |
> - GUEST_INTR_STATE_NMI));
> + (GUEST_INTR_STATE_MOV_SS | GUEST_INTR_STATE_NMI));
> }
>
> static bool vmx_get_nmi_mask(struct kvm_vcpu *vcpu)
--
Gleb.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] KVM: VMX: blocked-by-sti must not defer NMI injections
2010-05-11 13:16 [PATCH] KVM: VMX: blocked-by-sti must not defer NMI injections Jan Kiszka
2010-05-11 13:46 ` Gleb Natapov
@ 2010-05-12 20:05 ` Marcelo Tosatti
1 sibling, 0 replies; 3+ messages in thread
From: Marcelo Tosatti @ 2010-05-12 20:05 UTC (permalink / raw)
To: Jan Kiszka; +Cc: Avi Kivity, kvm, Gleb Natapov
On Tue, May 11, 2010 at 03:16:46PM +0200, Jan Kiszka wrote:
> As the processor may not consider GUEST_INTR_STATE_STI as a reason for
> blocking NMI, it could return immediately with EXIT_REASON_NMI_WINDOW
> when we asked for it. But as we consider this state as NMI-blocking, we
> can run into an endless loop.
>
> Resolve this by allowing NMI injection if just GUEST_INTR_STATE_STI is
> active (originally suggested by Gleb). Intel confirmed that this is
> safe, the processor will never complain about NMI injection in this
> state.
>
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> KVM-Stable-Tag
> ---
> arch/x86/kvm/vmx.c | 3 +--
> 1 files changed, 1 insertions(+), 2 deletions(-)
Applied, thanks.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2010-05-12 20:05 UTC | newest]
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2010-05-11 13:16 [PATCH] KVM: VMX: blocked-by-sti must not defer NMI injections Jan Kiszka
2010-05-11 13:46 ` Gleb Natapov
2010-05-12 20:05 ` Marcelo Tosatti
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