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[8/8] KVM: x86: SVM: remove vgif_enabled()

Message ID 20220322172449.235575-9-mlevitsk@redhat.com (mailing list archive)
State New, archived
Headers show
Series SVM fixes + refactoring | expand

Commit Message

Maxim Levitsky March 22, 2022, 5:24 p.m. UTC 
KVM always uses vgif when allowed, thus there is
no need to query current vmcb for it

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
 arch/x86/kvm/svm/svm.c | 12 ++++++------
 arch/x86/kvm/svm/svm.h | 12 ++++--------
 2 files changed, 10 insertions(+), 14 deletions(-)

Comments

Sean Christopherson March 30, 2022, 12:20 a.m. UTC | #1 
On Tue, Mar 22, 2022, Maxim Levitsky wrote:
> KVM always uses vgif when allowed, thus there is
> no need to query current vmcb for it

It'd be helpful to explicitly call out that KVM always takes V_GIF_ENABLE_MASK
from vmcs01, otherwise this looks like it does unintentend things when KVM is
runing vmcb02.

> Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
> ---
>  arch/x86/kvm/svm/svm.c | 12 ++++++------
>  arch/x86/kvm/svm/svm.h | 12 ++++--------
>  2 files changed, 10 insertions(+), 14 deletions(-)
> 
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index acf04cf4ed2a..70fc5897f5f2 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -172,7 +172,7 @@ static int vls = true;
>  module_param(vls, int, 0444);
>  
>  /* enable/disable Virtual GIF */
> -static int vgif = true;
> +int vgif = true;
>  module_param(vgif, int, 0444);

...

> @@ -453,14 +454,9 @@ static inline bool svm_is_intercept(struct vcpu_svm *svm, int bit)
>  	return vmcb_is_intercept(&svm->vmcb->control, bit);
>  }
>  
> -static inline bool vgif_enabled(struct vcpu_svm *svm)
> -{
> -	return !!(svm->vmcb->control.int_ctl & V_GIF_ENABLE_MASK);
Paolo Bonzini March 30, 2022, 12:08 p.m. UTC | #2 
On 3/30/22 02:20, Sean Christopherson wrote:
> It'd be helpful to explicitly call out that KVM always takes V_GIF_ENABLE_MASK
> from vmcs01, otherwise this looks like it does unintentend things when KVM is
> runing vmcb02.

I will add a note to the commit message.

More precisely, because KVM does not (as of this patch) support vGIF 
when L1 runs L2, the vmcb02's V_GIF_MASK and V_GIF_ENABLE_MASK also 
control L1's GIF and are the same as vmcs01's.

Paolo
diff mbox series

Patch

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index acf04cf4ed2a..70fc5897f5f2 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -172,7 +172,7 @@  static int vls = true;
 module_param(vls, int, 0444);
 
 /* enable/disable Virtual GIF */
-static int vgif = true;
+int vgif = true;
 module_param(vgif, int, 0444);
 
 /* enable/disable LBR virtualization */
@@ -2148,7 +2148,7 @@  void svm_set_gif(struct vcpu_svm *svm, bool value)
 		 * Likewise, clear the VINTR intercept, we will set it
 		 * again while processing KVM_REQ_EVENT if needed.
 		 */
-		if (vgif_enabled(svm))
+		if (vgif)
 			svm_clr_intercept(svm, INTERCEPT_STGI);
 		if (svm_is_intercept(svm, INTERCEPT_VINTR))
 			svm_clear_vintr(svm);
@@ -2166,7 +2166,7 @@  void svm_set_gif(struct vcpu_svm *svm, bool value)
 		 * in use, we still rely on the VINTR intercept (rather than
 		 * STGI) to detect an open interrupt window.
 		*/
-		if (!vgif_enabled(svm))
+		if (!vgif)
 			svm_clear_vintr(svm);
 	}
 }
@@ -3502,7 +3502,7 @@  static void svm_enable_irq_window(struct kvm_vcpu *vcpu)
 	 * enabled, the STGI interception will not occur. Enable the irq
 	 * window under the assumption that the hardware will set the GIF.
 	 */
-	if (vgif_enabled(svm) || gif_set(svm)) {
+	if (vgif || gif_set(svm)) {
 		/*
 		 * IRQ window is not needed when AVIC is enabled,
 		 * unless we have pending ExtINT since it cannot be injected
@@ -3522,7 +3522,7 @@  static void svm_enable_nmi_window(struct kvm_vcpu *vcpu)
 		return; /* IRET will cause a vm exit */
 
 	if (!gif_set(svm)) {
-		if (vgif_enabled(svm))
+		if (vgif)
 			svm_set_intercept(svm, INTERCEPT_STGI);
 		return; /* STGI will cause a vm exit */
 	}
@@ -4329,7 +4329,7 @@  static void svm_enable_smi_window(struct kvm_vcpu *vcpu)
 	struct vcpu_svm *svm = to_svm(vcpu);
 
 	if (!gif_set(svm)) {
-		if (vgif_enabled(svm))
+		if (vgif)
 			svm_set_intercept(svm, INTERCEPT_STGI);
 		/* STGI will cause a vm exit */
 	} else {
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 468f149556dd..6a10cb4817e8 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -33,6 +33,7 @@ 
 #define MSRPM_OFFSETS	16
 extern u32 msrpm_offsets[MSRPM_OFFSETS] __read_mostly;
 extern bool npt_enabled;
+extern int vgif;
 extern bool intercept_smi;
 
 /*
@@ -453,14 +454,9 @@  static inline bool svm_is_intercept(struct vcpu_svm *svm, int bit)
 	return vmcb_is_intercept(&svm->vmcb->control, bit);
 }
 
-static inline bool vgif_enabled(struct vcpu_svm *svm)
-{
-	return !!(svm->vmcb->control.int_ctl & V_GIF_ENABLE_MASK);
-}
-
 static inline void enable_gif(struct vcpu_svm *svm)
 {
-	if (vgif_enabled(svm))
+	if (vgif)
 		svm->vmcb->control.int_ctl |= V_GIF_MASK;
 	else
 		svm->vcpu.arch.hflags |= HF_GIF_MASK;
@@ -468,7 +464,7 @@  static inline void enable_gif(struct vcpu_svm *svm)
 
 static inline void disable_gif(struct vcpu_svm *svm)
 {
-	if (vgif_enabled(svm))
+	if (vgif)
 		svm->vmcb->control.int_ctl &= ~V_GIF_MASK;
 	else
 		svm->vcpu.arch.hflags &= ~HF_GIF_MASK;
@@ -476,7 +472,7 @@  static inline void disable_gif(struct vcpu_svm *svm)
 
 static inline bool gif_set(struct vcpu_svm *svm)
 {
-	if (vgif_enabled(svm))
+	if (vgif)
 		return !!(svm->vmcb->control.int_ctl & V_GIF_MASK);
 	else
 		return !!(svm->vcpu.arch.hflags & HF_GIF_MASK);