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Reply-To: Sean Christopherson <seanjc@google.com>
Date: Fri,  7 Jun 2024 10:26:08 -0700
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Subject: [PATCH 5/6] KVM: nVMX: Fold requested virtual interrupt check into has_nested_events()
From: Sean Christopherson <seanjc@google.com>
To: Sean Christopherson <seanjc@google.com>, Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, 
	Maxim Levitsky <mlevitsk@redhat.com>, Jim Mattson <jmattson@google.com>
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Check for a Requested Virtual Interrupt, i.e. a virtual interrupt that is
pending delivery, in vmx_has_nested_events() and drop the one-off
kvm_x86_ops.guest_apic_has_interrupt() hook.

In addition to dropping a superfluous hook, this fixes a bug where KVM
would incorrectly treat virtual interrupts _for L2_ as always enabled due
to kvm_arch_interrupt_allowed(), by way of vmx_interrupt_blocked(),
treating IRQs as enabled if L2 is active and vmcs12 is configured to exit
on IRQs, i.e. KVM would treat a virtual interrupt for L2 as a valid wake
event based on L1's IRQ blocking status.

Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/include/asm/kvm-x86-ops.h |  1 -
 arch/x86/include/asm/kvm_host.h    |  1 -
 arch/x86/kvm/vmx/main.c            |  1 -
 arch/x86/kvm/vmx/nested.c          |  4 ++++
 arch/x86/kvm/vmx/vmx.c             | 20 --------------------
 arch/x86/kvm/vmx/x86_ops.h         |  1 -
 arch/x86/kvm/x86.c                 | 10 +---------
 7 files changed, 5 insertions(+), 33 deletions(-)

diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 566d19b02483..f91d413d7de1 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -85,7 +85,6 @@ KVM_X86_OP_OPTIONAL(update_cr8_intercept)
 KVM_X86_OP(refresh_apicv_exec_ctrl)
 KVM_X86_OP_OPTIONAL(hwapic_irr_update)
 KVM_X86_OP_OPTIONAL(hwapic_isr_update)
-KVM_X86_OP_OPTIONAL_RET0(guest_apic_has_interrupt)
 KVM_X86_OP_OPTIONAL(load_eoi_exitmap)
 KVM_X86_OP_OPTIONAL(set_virtual_apic_mode)
 KVM_X86_OP_OPTIONAL(set_apic_access_page_addr)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 473f7e1d245c..f2336c646088 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1728,7 +1728,6 @@ struct kvm_x86_ops {
 	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);
-	bool (*guest_apic_has_interrupt)(struct kvm_vcpu *vcpu);
 	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);
diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index d0e1a5b5c915..7e846a842443 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -97,7 +97,6 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
 	.required_apicv_inhibits = VMX_REQUIRED_APICV_INHIBITS,
 	.hwapic_irr_update = vmx_hwapic_irr_update,
 	.hwapic_isr_update = vmx_hwapic_isr_update,
-	.guest_apic_has_interrupt = vmx_guest_apic_has_interrupt,
 	.sync_pir_to_irr = vmx_sync_pir_to_irr,
 	.deliver_interrupt = vmx_deliver_interrupt,
 	.dy_apicv_has_pending_interrupt = pi_has_pending_interrupt,
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 3bac65591f20..2392a7ef254d 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -4060,6 +4060,10 @@ static bool vmx_has_nested_events(struct kvm_vcpu *vcpu, bool for_injection)
 
 	vppr = *((u32 *)(vapic + APIC_PROCPRI));
 
+	max_irr = vmx_get_rvi();
+	if ((max_irr & 0xf0) > (vppr & 0xf0))
+		return true;
+
 	if (vmx->nested.pi_pending && vmx->nested.pi_desc &&
 	    pi_test_on(vmx->nested.pi_desc)) {
 		max_irr = pi_find_highest_vector(vmx->nested.pi_desc);
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index d8d9e1f6c340..c7558bcb0241 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -4106,26 +4106,6 @@ void pt_update_intercept_for_msr(struct kvm_vcpu *vcpu)
 	}
 }
 
-bool vmx_guest_apic_has_interrupt(struct kvm_vcpu *vcpu)
-{
-	struct vcpu_vmx *vmx = to_vmx(vcpu);
-	void *vapic_page;
-	u32 vppr;
-	int rvi;
-
-	if (WARN_ON_ONCE(!is_guest_mode(vcpu)) ||
-		!nested_cpu_has_vid(get_vmcs12(vcpu)) ||
-		WARN_ON_ONCE(!vmx->nested.virtual_apic_map.gfn))
-		return false;
-
-	rvi = vmx_get_rvi();
-
-	vapic_page = vmx->nested.virtual_apic_map.hva;
-	vppr = *((u32 *)(vapic_page + APIC_PROCPRI));
-
-	return ((rvi & 0xf0) > (vppr & 0xf0));
-}
-
 void vmx_msr_filter_changed(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
index 502704596c83..d404227c164d 100644
--- a/arch/x86/kvm/vmx/x86_ops.h
+++ b/arch/x86/kvm/vmx/x86_ops.h
@@ -49,7 +49,6 @@ void vmx_apicv_pre_state_restore(struct kvm_vcpu *vcpu);
 bool vmx_check_apicv_inhibit_reasons(enum kvm_apicv_inhibit reason);
 void vmx_hwapic_irr_update(struct kvm_vcpu *vcpu, int max_irr);
 void vmx_hwapic_isr_update(int max_isr);
-bool vmx_guest_apic_has_interrupt(struct kvm_vcpu *vcpu);
 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);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5ec24d9cb231..82442960b499 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -13133,12 +13133,6 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
 		kvm_arch_free_memslot(kvm, old);
 }
 
-static inline bool kvm_guest_apic_has_interrupt(struct kvm_vcpu *vcpu)
-{
-	return (is_guest_mode(vcpu) &&
-		static_call(kvm_x86_guest_apic_has_interrupt)(vcpu));
-}
-
 static inline bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu)
 {
 	if (!list_empty_careful(&vcpu->async_pf.done))
@@ -13172,9 +13166,7 @@ static inline bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu)
 	if (kvm_test_request(KVM_REQ_UPDATE_PROTECTED_GUEST_STATE, vcpu))
 		return true;
 
-	if (kvm_arch_interrupt_allowed(vcpu) &&
-	    (kvm_cpu_has_interrupt(vcpu) ||
-	    kvm_guest_apic_has_interrupt(vcpu)))
+	if (kvm_arch_interrupt_allowed(vcpu) && kvm_cpu_has_interrupt(vcpu))
 		return true;
 
 	if (kvm_hv_has_stimer_pending(vcpu))
-- 
2.45.2.505.gda0bf45e8d-goog