| Message ID | 20190322115702.10166-7-suravee.suthikulpanit@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM/x86: Add workaround to support ExtINT with AVIC | expand |
Hi Suravee. I wonder, how this interacts with Hyper-V SynIC; see comments below. On 22/03/2019 12.57, Suthikulpanit, Suravee wrote: > AMD AVIC does not support ExtINT. Therefore, AVIC must be temporary > deactivated and fall back to using legacy interrupt injection via > vINTR and interrupt window. > > Introduce svm_request_activate/deactivate_avic() helper functions, > which handle steps required to activate/deactivate AVIC. > > Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> > --- > arch/x86/kvm/svm.c | 57 +++++++++++++++++++++++++++++++++++++++++++--- > 1 file changed, 54 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c > index f41f34f70dde..84116e689d5f 100644 > --- a/arch/x86/kvm/svm.c > +++ b/arch/x86/kvm/svm.c > @@ -391,6 +391,8 @@ static u8 rsm_ins_bytes[] = "\x0f\xaa"; > static void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0); > static void svm_flush_tlb(struct kvm_vcpu *vcpu, bool invalidate_gpa); > static void svm_complete_interrupts(struct vcpu_svm *svm); > +static void svm_request_activate_avic(struct kvm_vcpu *vcpu); > +static bool svm_get_enable_apicv(struct kvm_vcpu *vcpu); > > static int nested_svm_exit_handled(struct vcpu_svm *svm); > static int nested_svm_intercept(struct vcpu_svm *svm); > @@ -2109,6 +2111,9 @@ static void avic_set_running(struct kvm_vcpu *vcpu, bool is_run) > { > struct vcpu_svm *svm = to_svm(vcpu); > > + if (!kvm_vcpu_apicv_active(vcpu)) > + return; > + > svm->avic_is_running = is_run; > if (is_run) > avic_vcpu_load(vcpu, vcpu->cpu); > @@ -2356,6 +2361,10 @@ static void svm_vcpu_blocking(struct kvm_vcpu *vcpu) > > static void svm_vcpu_unblocking(struct kvm_vcpu *vcpu) > { > + if (kvm_check_request(KVM_REQ_APICV_ACTIVATE, vcpu)) > + kvm_vcpu_activate_apicv(vcpu); > + if (kvm_check_request(KVM_REQ_APICV_DEACTIVATE, vcpu)) > + kvm_vcpu_deactivate_apicv(vcpu); > avic_set_running(vcpu, true); > } > > @@ -4505,6 +4514,15 @@ static int interrupt_window_interception(struct vcpu_svm *svm) > { > kvm_make_request(KVM_REQ_EVENT, &svm->vcpu); > svm_clear_vintr(svm); > + > + /* > + * For AVIC, the only reason to end up here is ExtINTs. > + * In this case AVIC was temporarily disabled for > + * requesting the IRQ window and we have to re-enable it. > + */ > + if (svm_get_enable_apicv(&svm->vcpu)) > + svm_request_activate_avic(&svm->vcpu); > + Are we sure, we're not accidentally re-enabling AVIC, if it was disabled via kvm_hv_activate_synic()? > svm->vmcb->control.int_ctl &= ~V_IRQ_MASK; > mark_dirty(svm->vmcb, VMCB_INTR); > ++svm->vcpu.stat.irq_window_exits; > @@ -5206,6 +5224,34 @@ static void svm_hwapic_isr_update(struct kvm_vcpu *vcpu, int max_isr) > { > } > > +static bool is_avic_active(struct vcpu_svm *svm) > +{ > + return (svm_get_enable_apicv(&svm->vcpu) && > + svm->vmcb->control.int_ctl & AVIC_ENABLE_MASK); > +} > + > +static void svm_request_activate_avic(struct kvm_vcpu *vcpu) > +{ > + struct vcpu_svm *svm = to_svm(vcpu); > + > + if (!lapic_in_kernel(vcpu) || is_avic_active(svm)) > + return; > + > + avic_setup_access_page(vcpu, false); > + kvm_make_apicv_activate_request(vcpu->kvm); > +} > + > +static void svm_request_deactivate_avic(struct kvm_vcpu *vcpu) > +{ > + struct vcpu_svm *svm = to_svm(vcpu); > + > + if (!lapic_in_kernel(vcpu) || !is_avic_active(svm)) > + return; > + > + avic_destroy_access_page(vcpu); Something like avic_destroy_access_page() is not called, when AVIC is disabled via kvm_hv_activate_synic(). Is that an oversight in the other code path, is it not needed here, or am I missing something? > + kvm_make_apicv_deactivate_request(vcpu->kvm); > +} > + > /* Note: Currently only used by Hyper-V. */ nit: This comment should probably go away, now. Regards Jan > static void svm_refresh_apicv_exec_ctrl(struct kvm_vcpu *vcpu) > { > @@ -5493,9 +5539,6 @@ static void enable_irq_window(struct kvm_vcpu *vcpu) > { > struct vcpu_svm *svm = to_svm(vcpu); > > - if (kvm_vcpu_apicv_active(vcpu)) > - return; > - > /* > * In case GIF=0 we can't rely on the CPU to tell us when GIF becomes > * 1, because that's a separate STGI/VMRUN intercept. The next time we > @@ -5505,6 +5548,14 @@ static void enable_irq_window(struct kvm_vcpu *vcpu) > * window under the assumption that the hardware will set the GIF. > */ > if ((vgif_enabled(svm) || gif_set(svm)) && nested_svm_intr(svm)) { > + /* > + * IRQ window is not needed when AVIC is enabled, > + * unless we have pending ExtINT since it cannot be injected > + * via AVIC. In such case, we need to temporarily disable AVIC, > + * and fallback to injecting IRQ via V_IRQ. > + */ > + if (kvm_vcpu_apicv_active(vcpu)) > + svm_request_deactivate_avic(&svm->vcpu); > svm_set_vintr(svm); > svm_inject_irq(svm, 0x0); > } >
Hi Jan, On 5/8/19 12:37 PM, Jan H. Schönherr wrote: > [CAUTION: External Email] > > Hi Suravee. > > I wonder, how this interacts with Hyper-V SynIC; see comments below. > > On 22/03/2019 12.57, Suthikulpanit, Suravee wrote: >> AMD AVIC does not support ExtINT. Therefore, AVIC must be temporary >> deactivated and fall back to using legacy interrupt injection via >> vINTR and interrupt window. >> >> Introduce svm_request_activate/deactivate_avic() helper functions, >> which handle steps required to activate/deactivate AVIC. >> >> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> >> --- >> arch/x86/kvm/svm.c | 57 +++++++++++++++++++++++++++++++++++++++++++--- >> 1 file changed, 54 insertions(+), 3 deletions(-) >> >> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c >> index f41f34f70dde..84116e689d5f 100644 >> --- a/arch/x86/kvm/svm.c >> +++ b/arch/x86/kvm/svm.c >> @@ -391,6 +391,8 @@ static u8 rsm_ins_bytes[] = "\x0f\xaa"; >> static void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0); >> static void svm_flush_tlb(struct kvm_vcpu *vcpu, bool invalidate_gpa); >> static void svm_complete_interrupts(struct vcpu_svm *svm); >> +static void svm_request_activate_avic(struct kvm_vcpu *vcpu); >> +static bool svm_get_enable_apicv(struct kvm_vcpu *vcpu); >> >> static int nested_svm_exit_handled(struct vcpu_svm *svm); >> static int nested_svm_intercept(struct vcpu_svm *svm); >> @@ -2109,6 +2111,9 @@ static void avic_set_running(struct kvm_vcpu *vcpu, bool is_run) >> { >> struct vcpu_svm *svm = to_svm(vcpu); >> >> + if (!kvm_vcpu_apicv_active(vcpu)) >> + return; >> + >> svm->avic_is_running = is_run; >> if (is_run) >> avic_vcpu_load(vcpu, vcpu->cpu); >> @@ -2356,6 +2361,10 @@ static void svm_vcpu_blocking(struct kvm_vcpu *vcpu) >> >> static void svm_vcpu_unblocking(struct kvm_vcpu *vcpu) >> { >> + if (kvm_check_request(KVM_REQ_APICV_ACTIVATE, vcpu)) >> + kvm_vcpu_activate_apicv(vcpu); >> + if (kvm_check_request(KVM_REQ_APICV_DEACTIVATE, vcpu)) >> + kvm_vcpu_deactivate_apicv(vcpu); >> avic_set_running(vcpu, true); >> } >> >> @@ -4505,6 +4514,15 @@ static int interrupt_window_interception(struct vcpu_svm *svm) >> { >> kvm_make_request(KVM_REQ_EVENT, &svm->vcpu); >> svm_clear_vintr(svm); >> + >> + /* >> + * For AVIC, the only reason to end up here is ExtINTs. >> + * In this case AVIC was temporarily disabled for >> + * requesting the IRQ window and we have to re-enable it. >> + */ >> + if (svm_get_enable_apicv(&svm->vcpu)) >> + svm_request_activate_avic(&svm->vcpu); >> + > > Are we sure, we're not accidentally re-enabling AVIC, if it was disabled via > kvm_hv_activate_synic()? Actually, I missed this case. Now I have a solution that I'll be send out for review in V2. >> svm->vmcb->control.int_ctl &= ~V_IRQ_MASK; >> mark_dirty(svm->vmcb, VMCB_INTR); >> ++svm->vcpu.stat.irq_window_exits; >> @@ -5206,6 +5224,34 @@ static void svm_hwapic_isr_update(struct kvm_vcpu *vcpu, int max_isr) >> { >> } >> >> +static bool is_avic_active(struct vcpu_svm *svm) >> +{ >> + return (svm_get_enable_apicv(&svm->vcpu) && >> + svm->vmcb->control.int_ctl & AVIC_ENABLE_MASK); >> +} >> + >> +static void svm_request_activate_avic(struct kvm_vcpu *vcpu) >> +{ >> + struct vcpu_svm *svm = to_svm(vcpu); >> + >> + if (!lapic_in_kernel(vcpu) || is_avic_active(svm)) >> + return; >> + >> + avic_setup_access_page(vcpu, false); >> + kvm_make_apicv_activate_request(vcpu->kvm); >> +} >> + >> +static void svm_request_deactivate_avic(struct kvm_vcpu *vcpu) >> +{ >> + struct vcpu_svm *svm = to_svm(vcpu); >> + >> + if (!lapic_in_kernel(vcpu) || !is_avic_active(svm)) >> + return; >> + >> + avic_destroy_access_page(vcpu); > > Something like avic_destroy_access_page() is not called, when AVIC is > disabled via kvm_hv_activate_synic(). > > Is that an oversight in the other code path, is it not needed here, > or am I missing something? This is an oversight. I also have a fix for this in V2. Thanks, Suravee
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index f41f34f70dde..84116e689d5f 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -391,6 +391,8 @@ static u8 rsm_ins_bytes[] = "\x0f\xaa"; static void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0); static void svm_flush_tlb(struct kvm_vcpu *vcpu, bool invalidate_gpa); static void svm_complete_interrupts(struct vcpu_svm *svm); +static void svm_request_activate_avic(struct kvm_vcpu *vcpu); +static bool svm_get_enable_apicv(struct kvm_vcpu *vcpu); static int nested_svm_exit_handled(struct vcpu_svm *svm); static int nested_svm_intercept(struct vcpu_svm *svm); @@ -2109,6 +2111,9 @@ static void avic_set_running(struct kvm_vcpu *vcpu, bool is_run) { struct vcpu_svm *svm = to_svm(vcpu); + if (!kvm_vcpu_apicv_active(vcpu)) + return; + svm->avic_is_running = is_run; if (is_run) avic_vcpu_load(vcpu, vcpu->cpu); @@ -2356,6 +2361,10 @@ static void svm_vcpu_blocking(struct kvm_vcpu *vcpu) static void svm_vcpu_unblocking(struct kvm_vcpu *vcpu) { + if (kvm_check_request(KVM_REQ_APICV_ACTIVATE, vcpu)) + kvm_vcpu_activate_apicv(vcpu); + if (kvm_check_request(KVM_REQ_APICV_DEACTIVATE, vcpu)) + kvm_vcpu_deactivate_apicv(vcpu); avic_set_running(vcpu, true); } @@ -4505,6 +4514,15 @@ static int interrupt_window_interception(struct vcpu_svm *svm) { kvm_make_request(KVM_REQ_EVENT, &svm->vcpu); svm_clear_vintr(svm); + + /* + * For AVIC, the only reason to end up here is ExtINTs. + * In this case AVIC was temporarily disabled for + * requesting the IRQ window and we have to re-enable it. + */ + if (svm_get_enable_apicv(&svm->vcpu)) + svm_request_activate_avic(&svm->vcpu); + svm->vmcb->control.int_ctl &= ~V_IRQ_MASK; mark_dirty(svm->vmcb, VMCB_INTR); ++svm->vcpu.stat.irq_window_exits; @@ -5206,6 +5224,34 @@ static void svm_hwapic_isr_update(struct kvm_vcpu *vcpu, int max_isr) { } +static bool is_avic_active(struct vcpu_svm *svm) +{ + return (svm_get_enable_apicv(&svm->vcpu) && + svm->vmcb->control.int_ctl & AVIC_ENABLE_MASK); +} + +static void svm_request_activate_avic(struct kvm_vcpu *vcpu) +{ + struct vcpu_svm *svm = to_svm(vcpu); + + if (!lapic_in_kernel(vcpu) || is_avic_active(svm)) + return; + + avic_setup_access_page(vcpu, false); + kvm_make_apicv_activate_request(vcpu->kvm); +} + +static void svm_request_deactivate_avic(struct kvm_vcpu *vcpu) +{ + struct vcpu_svm *svm = to_svm(vcpu); + + if (!lapic_in_kernel(vcpu) || !is_avic_active(svm)) + return; + + avic_destroy_access_page(vcpu); + kvm_make_apicv_deactivate_request(vcpu->kvm); +} + /* Note: Currently only used by Hyper-V. */ static void svm_refresh_apicv_exec_ctrl(struct kvm_vcpu *vcpu) { @@ -5493,9 +5539,6 @@ static void enable_irq_window(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu); - if (kvm_vcpu_apicv_active(vcpu)) - return; - /* * In case GIF=0 we can't rely on the CPU to tell us when GIF becomes * 1, because that's a separate STGI/VMRUN intercept. The next time we @@ -5505,6 +5548,14 @@ static void enable_irq_window(struct kvm_vcpu *vcpu) * window under the assumption that the hardware will set the GIF. */ if ((vgif_enabled(svm) || gif_set(svm)) && nested_svm_intr(svm)) { + /* + * IRQ window is not needed when AVIC is enabled, + * unless we have pending ExtINT since it cannot be injected + * via AVIC. In such case, we need to temporarily disable AVIC, + * and fallback to injecting IRQ via V_IRQ. + */ + if (kvm_vcpu_apicv_active(vcpu)) + svm_request_deactivate_avic(&svm->vcpu); svm_set_vintr(svm); svm_inject_irq(svm, 0x0); }
AMD AVIC does not support ExtINT. Therefore, AVIC must be temporary deactivated and fall back to using legacy interrupt injection via vINTR and interrupt window. Introduce svm_request_activate/deactivate_avic() helper functions, which handle steps required to activate/deactivate AVIC. Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> --- arch/x86/kvm/svm.c | 57 +++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 54 insertions(+), 3 deletions(-)