From: Sean Christopherson <seanjc@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx>
---
TDX interrupts breakout:
- 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 684777c2f0a4..474e0a7c1069 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1789,8 +1789,17 @@ 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;
--
2.46.0
