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Subject[RFC PATCH v5 075/104] KVM: x86: Check for pending APICv interrupt in kvm_vcpu_has_events()
Date
From: Sean Christopherson <sean.j.christopherson@intel.com>

Return true for kvm_vcpu_has_events() if the vCPU has a pending APICv
interrupt to support TDX's usage of APICv. Unlike VMX, TDX doesn't have
access to vmcs.GUEST_INTR_STATUS and so can't emulate posted interrupts,
i.e. needs to generate a posted interrupt and more importantly can't
manually move requested interrupts into the vIRR (which it also doesn't
have access to).

Because pi_has_pending_interrupt() is heavy operation which uses two atomic
test bit operations and one atomic 256 bit bitmap check, introduce new
callback for this check instead of reusing dy_apicv_has_pending_interrupt()
callback to avoid affecting the exiting code.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/vmx/main.c | 9 +++++++++
arch/x86/kvm/x86.c | 5 ++++-
3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 489374a57b66..8dab9f16f559 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1491,6 +1491,7 @@ struct kvm_x86_ops {
void (*start_assignment)(struct kvm *kvm);
void (*apicv_post_state_restore)(struct kvm_vcpu *vcpu);
bool (*dy_apicv_has_pending_interrupt)(struct kvm_vcpu *vcpu);
+ bool (*apicv_has_pending_interrupt)(struct kvm_vcpu *vcpu);

int (*set_hv_timer)(struct kvm_vcpu *vcpu, u64 guest_deadline_tsc,
bool *expired);
diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index 882358ac270b..d75caf0d6861 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -148,6 +148,14 @@ static void vt_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
return vmx_vcpu_load(vcpu, cpu);
}

+static bool vt_apicv_has_pending_interrupt(struct kvm_vcpu *vcpu)
+{
+ if (is_td_vcpu(vcpu))
+ return pi_has_pending_interrupt(vcpu);
+
+ return false;
+}
+
static void vt_flush_tlb_all(struct kvm_vcpu *vcpu)
{
if (is_td_vcpu(vcpu))
@@ -297,6 +305,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
.sync_pir_to_irr = vmx_sync_pir_to_irr,
.deliver_interrupt = vmx_deliver_interrupt,
.dy_apicv_has_pending_interrupt = pi_has_pending_interrupt,
+ .apicv_has_pending_interrupt = vt_apicv_has_pending_interrupt,

.set_tss_addr = vmx_set_tss_addr,
.set_identity_map_addr = vmx_set_identity_map_addr,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 89d04cd64cd0..314ae43e07bf 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -12111,7 +12111,10 @@ static inline bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu)

if (kvm_arch_interrupt_allowed(vcpu) &&
(kvm_cpu_has_interrupt(vcpu) ||
- kvm_guest_apic_has_interrupt(vcpu)))
+ kvm_guest_apic_has_interrupt(vcpu) ||
+ (vcpu->arch.apicv_active &&
+ kvm_x86_ops.apicv_has_pending_interrupt &&
+ kvm_x86_ops.apicv_has_pending_interrupt(vcpu))))
return true;

if (kvm_hv_has_stimer_pending(vcpu))
--
2.25.1
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