KVM: x86: Plumb in the vCPU to kvm_x86_ops.hwapic_isr_update()

Pass the target vCPU to the hwapic_isr_update() vendor hook so that VMX
can defer the update until after nested VM-Exit if an EOI for L1's vAPIC
occurs while L2 is active.

Note, commit d39850f ("KVM: x86: Drop @vcpu parameter from
kvm_x86_ops.hwapic_isr_update()") removed the parameter with the
justification that doing so "allows for a decent amount of (future)
cleanup in the APIC code", but it's not at all clear what cleanup was
intended, or if it was ever realized.

No functional change intended.

Cc: stable@vger.kernel.org
Reviewed-by: Chao Gao <chao.gao@intel.com>
Tested-by: Chao Gao <chao.gao@intel.com>
Link: https://lore.kernel.org/r/20241128000010.4051275-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: sean-jc

arch/x86/include/asm/kvm_host.h

@@ -1735,7 +1735,7 @@ struct kvm_x86_ops {
 	bool allow_apicv_in_x2apic_without_x2apic_virtualization;
 	void (*refresh_apicv_exec_ctrl)(struct kvm_vcpu *vcpu);
 	void (*hwapic_irr_update)(struct kvm_vcpu *vcpu, int max_irr);
-	void (*hwapic_isr_update)(int isr);
+	void (*hwapic_isr_update)(struct kvm_vcpu *vcpu, int isr);
 	void (*load_eoi_exitmap)(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap);
 	void (*set_virtual_apic_mode)(struct kvm_vcpu *vcpu);
 	void (*set_apic_access_page_addr)(struct kvm_vcpu *vcpu);

arch/x86/kvm/lapic.c

@@ -763,7 +763,7 @@ static inline void apic_set_isr(int vec, struct kvm_lapic *apic)
 	 * just set SVI.
 	 */
 	if (unlikely(apic->apicv_active))
-		kvm_x86_call(hwapic_isr_update)(vec);
+		kvm_x86_call(hwapic_isr_update)(apic->vcpu, vec);
 	else {
 		++apic->isr_count;
 		BUG_ON(apic->isr_count > MAX_APIC_VECTOR);
@@ -808,7 +808,7 @@ static inline void apic_clear_isr(int vec, struct kvm_lapic *apic)
 	 * and must be left alone.
 	 */
 	if (unlikely(apic->apicv_active))
-		kvm_x86_call(hwapic_isr_update)(apic_find_highest_isr(apic));
+		kvm_x86_call(hwapic_isr_update)(apic->vcpu, apic_find_highest_isr(apic));
 	else {
 		--apic->isr_count;
 		BUG_ON(apic->isr_count < 0);
@@ -2806,7 +2806,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event)
 	if (apic->apicv_active) {
 		kvm_x86_call(apicv_post_state_restore)(vcpu);
 		kvm_x86_call(hwapic_irr_update)(vcpu, -1);
-		kvm_x86_call(hwapic_isr_update)(-1);
+		kvm_x86_call(hwapic_isr_update)(vcpu, -1);
 	}
 
 	vcpu->arch.apic_arb_prio = 0;
@@ -3121,9 +3121,8 @@ int kvm_apic_set_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s)
 	kvm_apic_update_apicv(vcpu);
 	if (apic->apicv_active) {
 		kvm_x86_call(apicv_post_state_restore)(vcpu);
-		kvm_x86_call(hwapic_irr_update)(vcpu,
-						apic_find_highest_irr(apic));
-		kvm_x86_call(hwapic_isr_update)(apic_find_highest_isr(apic));
+		kvm_x86_call(hwapic_irr_update)(vcpu, apic_find_highest_irr(apic));
+		kvm_x86_call(hwapic_isr_update)(vcpu, apic_find_highest_isr(apic));
 	}
 	kvm_make_request(KVM_REQ_EVENT, vcpu);
 	if (ioapic_in_kernel(vcpu->kvm))

arch/x86/kvm/vmx/vmx.c

@@ -6862,7 +6862,7 @@ void vmx_set_apic_access_page_addr(struct kvm_vcpu *vcpu)
 	read_unlock(&vcpu->kvm->mmu_lock);
 }
 
-void vmx_hwapic_isr_update(int max_isr)
+void vmx_hwapic_isr_update(struct kvm_vcpu *vcpu, int max_isr)
 {
 	u16 status;
 	u8 old;

arch/x86/kvm/vmx/x86_ops.h

@@ -48,7 +48,7 @@ void vmx_migrate_timers(struct kvm_vcpu *vcpu);
 void vmx_set_virtual_apic_mode(struct kvm_vcpu *vcpu);
 void vmx_apicv_pre_state_restore(struct kvm_vcpu *vcpu);
 void vmx_hwapic_irr_update(struct kvm_vcpu *vcpu, int max_irr);
-void vmx_hwapic_isr_update(int max_isr);
+void vmx_hwapic_isr_update(struct kvm_vcpu *vcpu, int max_isr);
 int vmx_sync_pir_to_irr(struct kvm_vcpu *vcpu);
 void vmx_deliver_interrupt(struct kvm_lapic *apic, int delivery_mode,
 			   int trig_mode, int vector);