kvm: vmx: Basic APIC virtualization controls have three settings

Previously, we toggled between SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE
and SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES, depending on whether or
not the EXTD bit was set in MSR_IA32_APICBASE. However, if the local
APIC is disabled, we should not set either of these APIC
virtualization control bits.
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -995,7 +995,7 @@ struct kvm_x86_ops {
 	void (*hwapic_irr_update)(struct kvm_vcpu *vcpu, int max_irr);
 	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_x2apic_mode)(struct kvm_vcpu *vcpu, bool set);
+	void (*set_virtual_apic_mode)(struct kvm_vcpu *vcpu);
 	void (*set_apic_access_page_addr)(struct kvm_vcpu *vcpu, hpa_t hpa);
 	void (*deliver_posted_interrupt)(struct kvm_vcpu *vcpu, int vector);
 	int (*sync_pir_to_irr)(struct kvm_vcpu *vcpu);

arch/x86/kvm/lapic.c

@@ -1990,13 +1990,11 @@ void kvm_lapic_set_base(struct kvm_vcpu *vcpu, u64 value)
 		}
 	}
 
-	if ((old_value ^ value) & X2APIC_ENABLE) {
-		if (value & X2APIC_ENABLE) {
+	if (((old_value ^ value) & X2APIC_ENABLE) && (value & X2APIC_ENABLE))
 		kvm_apic_set_x2apic_id(apic, vcpu->vcpu_id);
-			kvm_x86_ops->set_virtual_x2apic_mode(vcpu, true);
-		} else
-			kvm_x86_ops->set_virtual_x2apic_mode(vcpu, false);
-	}
+
+	if ((old_value ^ value) & (MSR_IA32_APICBASE_ENABLE | X2APIC_ENABLE))
+		kvm_x86_ops->set_virtual_apic_mode(vcpu);
 
 	apic->base_address = apic->vcpu->arch.apic_base &
 			     MSR_IA32_APICBASE_BASE;

arch/x86/kvm/svm.c

@@ -5036,7 +5036,7 @@ static void update_cr8_intercept(struct kvm_vcpu *vcpu, int tpr, int irr)
 		set_cr_intercept(svm, INTERCEPT_CR8_WRITE);
 }
 
-static void svm_set_virtual_x2apic_mode(struct kvm_vcpu *vcpu, bool set)
+static void svm_set_virtual_apic_mode(struct kvm_vcpu *vcpu)
 {
 	return;
 }
@@ -7076,7 +7076,7 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
 	.enable_nmi_window = enable_nmi_window,
 	.enable_irq_window = enable_irq_window,
 	.update_cr8_intercept = update_cr8_intercept,
-	.set_virtual_x2apic_mode = svm_set_virtual_x2apic_mode,
+	.set_virtual_apic_mode = svm_set_virtual_apic_mode,
 	.get_enable_apicv = svm_get_enable_apicv,
 	.refresh_apicv_exec_ctrl = svm_refresh_apicv_exec_ctrl,
 	.load_eoi_exitmap = svm_load_eoi_exitmap,

arch/x86/kvm/vmx.c

@@ -481,7 +481,8 @@ struct nested_vmx {
 	bool sync_shadow_vmcs;
 	bool dirty_vmcs12;
 
-	bool change_vmcs01_virtual_x2apic_mode;
+	bool change_vmcs01_virtual_apic_mode;
+
 	/* L2 must run next, and mustn't decide to exit to L1. */
 	bool nested_run_pending;
 
@@ -9281,32 +9282,44 @@ static void update_cr8_intercept(struct kvm_vcpu *vcpu, int tpr, int irr)
 	vmcs_write32(TPR_THRESHOLD, irr);
 }
 
-static void vmx_set_virtual_x2apic_mode(struct kvm_vcpu *vcpu, bool set)
+static void vmx_set_virtual_apic_mode(struct kvm_vcpu *vcpu)
 {
 	u32 sec_exec_control;
 
+	if (!lapic_in_kernel(vcpu))
+		return;
+
 	/* Postpone execution until vmcs01 is the current VMCS. */
 	if (is_guest_mode(vcpu)) {
-		to_vmx(vcpu)->nested.change_vmcs01_virtual_x2apic_mode = true;
+		to_vmx(vcpu)->nested.change_vmcs01_virtual_apic_mode = true;
 		return;
 	}
 
-	if (!cpu_has_vmx_virtualize_x2apic_mode())
-		return;
-
 	if (!cpu_need_tpr_shadow(vcpu))
 		return;
 
 	sec_exec_control = vmcs_read32(SECONDARY_VM_EXEC_CONTROL);
+	sec_exec_control &= ~(SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES |
+			      SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE);
 
-	if (set) {
-		sec_exec_control &= ~SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
-		sec_exec_control |= SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE;
-	} else {
-		sec_exec_control &= ~SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE;
-		sec_exec_control |= SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
+	switch (kvm_get_apic_mode(vcpu)) {
+	case LAPIC_MODE_INVALID:
+		WARN_ONCE(true, "Invalid local APIC state");
+	case LAPIC_MODE_DISABLED:
+		break;
+	case LAPIC_MODE_XAPIC:
+		if (flexpriority_enabled) {
+			sec_exec_control |=
+				SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
 			vmx_flush_tlb(vcpu, true);
 		}
+		break;
+	case LAPIC_MODE_X2APIC:
+		if (cpu_has_vmx_virtualize_x2apic_mode())
+			sec_exec_control |=
+				SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE;
+		break;
+	}
 	vmcs_write32(SECONDARY_VM_EXEC_CONTROL, sec_exec_control);
 
 	vmx_update_msr_bitmap(vcpu);
@@ -12087,10 +12100,9 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason,
 	if (kvm_has_tsc_control)
 		decache_tsc_multiplier(vmx);
 
-	if (vmx->nested.change_vmcs01_virtual_x2apic_mode) {
-		vmx->nested.change_vmcs01_virtual_x2apic_mode = false;
-		vmx_set_virtual_x2apic_mode(vcpu,
-				vcpu->arch.apic_base & X2APIC_ENABLE);
+	if (vmx->nested.change_vmcs01_virtual_apic_mode) {
+		vmx->nested.change_vmcs01_virtual_apic_mode = false;
+		vmx_set_virtual_apic_mode(vcpu);
 	} else if (!nested_cpu_has_ept(vmcs12) &&
 		   nested_cpu_has2(vmcs12,
 				   SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES)) {
@@ -12718,7 +12730,7 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = {
 	.enable_nmi_window = enable_nmi_window,
 	.enable_irq_window = enable_irq_window,
 	.update_cr8_intercept = update_cr8_intercept,
-	.set_virtual_x2apic_mode = vmx_set_virtual_x2apic_mode,
+	.set_virtual_apic_mode = vmx_set_virtual_apic_mode,
 	.set_apic_access_page_addr = vmx_set_apic_access_page_addr,
 	.get_enable_apicv = vmx_get_enable_apicv,
 	.refresh_apicv_exec_ctrl = vmx_refresh_apicv_exec_ctrl,