| Message ID | 20250211025828.3072076-6-binbin.wu@linux.intel.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | KVM: TDX: TDX interrupts | expand |
On Tue, Feb 11, 2025 at 10:58:16AM +0800, Binbin Wu wrote: >From: Sean Christopherson <seanjc@google.com> > >If APIC state is protected, i.e. the vCPU is a TDX guest, assume a timer >IRQ was injected when deciding whether or not to busy wait in the "timer >advanced" path. The "real" vIRR is not readable/writable, so trying to >query for a pending timer IRQ will return garbage. > >Note, TDX can scour the PIR if it wants to be more precise and skip the >"wait" call entirely. > >Signed-off-by: Sean Christopherson <seanjc@google.com> >Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com> >--- >TDX interrupts v2: >- No change. > >TDX interrupts v1: >- Renamed from "KVM: x86: Assume timer IRQ was injected if APIC state is proteced" > to "KVM: x86: Assume timer IRQ was injected if APIC state is protected", i.e., > fix the typo 'proteced'. >--- > arch/x86/kvm/lapic.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > >diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c >index bbdede07d063..bab5c42f63b7 100644 >--- a/arch/x86/kvm/lapic.c >+++ b/arch/x86/kvm/lapic.c >@@ -1797,8 +1797,17 @@ static void apic_update_lvtt(struct kvm_lapic *apic) > static bool lapic_timer_int_injected(struct kvm_vcpu *vcpu) > { > struct kvm_lapic *apic = vcpu->arch.apic; >- u32 reg = kvm_lapic_get_reg(apic, APIC_LVTT); >+ u32 reg; > >+ /* >+ * Assume a timer IRQ was "injected" if the APIC is protected. KVM's >+ * copy of the vIRR is bogus, it's the responsibility of the caller to >+ * precisely check whether or not a timer IRQ is pending. >+ */ >+ if (apic->guest_apic_protected) >+ return true; >+ >+ reg = kvm_lapic_get_reg(apic, APIC_LVTT); nit: ^^ remove one space here > if (kvm_apic_hw_enabled(apic)) { > int vec = reg & APIC_VECTOR_MASK; > void *bitmap = apic->regs + APIC_ISR; >-- >2.46.0 >
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index bbdede07d063..bab5c42f63b7 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -1797,8 +1797,17 @@ static void apic_update_lvtt(struct kvm_lapic *apic) static bool lapic_timer_int_injected(struct kvm_vcpu *vcpu) { struct kvm_lapic *apic = vcpu->arch.apic; - u32 reg = kvm_lapic_get_reg(apic, APIC_LVTT); + u32 reg; + /* + * Assume a timer IRQ was "injected" if the APIC is protected. KVM's + * copy of the vIRR is bogus, it's the responsibility of the caller to + * precisely check whether or not a timer IRQ is pending. + */ + if (apic->guest_apic_protected) + return true; + + reg = kvm_lapic_get_reg(apic, APIC_LVTT); if (kvm_apic_hw_enabled(apic)) { int vec = reg & APIC_VECTOR_MASK; void *bitmap = apic->regs + APIC_ISR;