KVM: TDX: Wait lapic expire when timer IRQ was injected

Call kvm_wait_lapic_expire() when POSTED_INTR_ON is set and the vector
for LVTT is set in PIR before TD entry.

KVM always assumes a timer IRQ was injected if APIC state is protected.
For TDX guest, APIC state is protected and KVM injects timer IRQ via posted
interrupt.  To avoid unnecessary wait calls, only call
kvm_wait_lapic_expire() when a timer IRQ was injected, i.e., POSTED_INTR_ON
is set and the vector for LVTT is set in PIR.

Add a helper to test PIR.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Co-developed-by: Binbin Wu <binbin.wu@linux.intel.com>
Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
Message-ID: <20250222014757.897978-7-binbin.wu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/include/asm/posted_intr.h b/arch/x86/include/asm/posted_intr.h
index de788b400fba43860192d8ec0d688a6d662f48b9..bb107ebbe7131b3bc917b265e5bc1af9da534acd 100644 (file)
--- a/arch/x86/include/asm/posted_intr.h
+++ b/arch/x86/include/asm/posted_intr.h
@@ -81,6 +81,11 @@ static inline bool pi_test_sn(struct pi_desc *pi_desc)
        return test_bit(POSTED_INTR_SN, (unsigned long *)&pi_desc->control);
 }
 
+static inline bool pi_test_pir(int vector, struct pi_desc *pi_desc)
+{
+       return test_bit(vector, (unsigned long *)pi_desc->pir);
+}
+
 /* Non-atomic helpers */
 static inline void __pi_set_sn(struct pi_desc *pi_desc)
 {

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 798ea5a5232ecdbadf297a4902fb9dfa20644e81..b98eab24114c722b3ff25a941487087bd7351f2b 100644 (file)
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -969,9 +969,14 @@ fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu, bool force_immediate_exit)
 
        trace_kvm_entry(vcpu, force_immediate_exit);
 
-       if (pi_test_on(&vt->pi_desc))
+       if (pi_test_on(&vt->pi_desc)) {
                apic->send_IPI_self(POSTED_INTR_VECTOR);
 
+               if (pi_test_pir(kvm_lapic_get_reg(vcpu->arch.apic, APIC_LVTT) &
+                              APIC_VECTOR_MASK, &vt->pi_desc))
+                       kvm_wait_lapic_expire(vcpu);
+       }
+
        tdx_vcpu_enter_exit(vcpu);
 
        if (vt->host_debugctlmsr & ~TDX_DEBUGCTL_PRESERVED)