[RFC PATCH 2/9] KVM: SVM: Add support for Alternate Injection for the SEV-SNP #HV doorbell page NAE event

[Melody Wang]

To support Alternate Injection, there are three new NAE
events added in the spec:

1. "configure Injection Notification Vector": configures the interrupt
   vector that will be used by the hypervisor whenever it needs to
   notify the SVSM that the interrupt processing for VMPL1-3 is
   required

2. "Specific EOI" - requests the hypervisor to perform an EOI cycle on
   level-sensitive interrupt, and

3. "Disable Alternate Injection" - requests the hypervisor to disable
   Alternate Injection for a specific VMPL.

Implement the first two.

Signed-off-by: Melody Wang <huibo.wang@xxxxxxx>
---
 arch/x86/include/uapi/asm/svm.h |  2 ++
 arch/x86/kvm/lapic.c            |  3 ++-
 arch/x86/kvm/lapic.h            |  1 +
 arch/x86/kvm/svm/sev.c          | 40 +++++++++++++++++++++++++++++++--
 arch/x86/kvm/svm/svm.h          |  1 +
 5 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/uapi/asm/svm.h b/arch/x86/include/uapi/asm/svm.h
index 60b7a52f6f7e..786f50f33457 100644
--- a/arch/x86/include/uapi/asm/svm.h
+++ b/arch/x86/include/uapi/asm/svm.h
@@ -127,6 +127,8 @@
 #define SVM_VMGEXIT_AP_VMPL_SHIFT		16
 #define SVM_VMGEXIT_GET_APIC_IDS		0x80000017ull
 #define SVM_VMGEXIT_SNP_RUN_VMPL		0x80000018ull
+#define SVM_VMGEXIT_SNP_CONFIG_INT_INJ		0x8000001bull
+#define SVM_VMGEXIT_SVSM_SPECIFIC_EOI		0x8000001dull
 #define SVM_VMGEXIT_SAVIC			0x8000001aull
 #define SVM_VMGEXIT_SAVIC_REGISTER_GPA		0
 #define SVM_VMGEXIT_SAVIC_UNREGISTER_GPA	1
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index dc7a08831a54..9ebae1052f64 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1543,7 +1543,7 @@ static bool kvm_ioapic_handles_vector(struct kvm_lapic *apic, int vector)
 	return test_bit(vector, apic->vcpu->arch.ioapic_handled_vectors);
 }
 
-static void kvm_ioapic_send_eoi(struct kvm_lapic *apic, int vector)
+void kvm_ioapic_send_eoi(struct kvm_lapic *apic, int vector)
 {
 	int __maybe_unused trigger_mode;
 
@@ -1584,6 +1584,7 @@ static void kvm_ioapic_send_eoi(struct kvm_lapic *apic, int vector)
 	kvm_ioapic_update_eoi(apic->vcpu, vector, trigger_mode);
 #endif
 }
+EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_ioapic_send_eoi);
 
 static int apic_set_eoi(struct kvm_lapic *apic)
 {
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index a9ede0e145d9..9d202ef3016b 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -254,6 +254,7 @@ void kvm_lapic_switch_to_hv_timer(struct kvm_vcpu *vcpu);
 void kvm_lapic_expired_hv_timer(struct kvm_vcpu *vcpu);
 bool kvm_lapic_hv_timer_in_use(struct kvm_vcpu *vcpu);
 void kvm_lapic_restart_hv_timer(struct kvm_vcpu *vcpu);
+void kvm_ioapic_send_eoi(struct kvm_lapic *apic, int vector);
 
 static inline enum lapic_mode kvm_apic_mode(u64 apic_base)
 {
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 0736e1c778d9..924c1b968fdc 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -3432,6 +3432,8 @@ static void sev_es_sync_from_ghcb(struct vcpu_svm *svm)
 	memset(ghcb->save.valid_bitmap, 0, sizeof(ghcb->save.valid_bitmap));
 }
 
+#define SVM_SEV_VMPL_MAX        4
+
 static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
 {
 	struct vmcb_control_area *control = &svm->vmcb->control;
@@ -3566,6 +3568,21 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
 		if (!sev_snp_guest(vcpu->kvm))
 			goto vmgexit_err;
 		break;
+	case SVM_VMGEXIT_SNP_CONFIG_INT_INJ:
+		if (!sev_snp_guest(vcpu->kvm))
+			goto vmgexit_err;
+		break;
+	case SVM_VMGEXIT_SVSM_SPECIFIC_EOI: {
+		u8 vmpl;
+
+		if (!sev_snp_guest(vcpu->kvm))
+			goto vmgexit_err;
+
+		vmpl = (control->exit_info_1 >> 16) & 0xff;
+		if (vmpl >= SVM_SEV_VMPL_MAX)
+			goto vmgexit_err;
+		break;
+	}
 	default:
 		reason = GHCB_ERR_INVALID_EVENT;
 		goto vmgexit_err;
@@ -4217,8 +4234,6 @@ static unsigned int get_ap_creation_apic_id(struct vcpu_svm *svm)
 	return upper_32_bits(svm->vmcb->control.exit_info_1);
 }
 
-#define SVM_SEV_VMPL_MAX	4
-
 static int sev_snp_ap_creation(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *target_svm = NULL, *svm = to_svm(vcpu);
@@ -4953,6 +4968,27 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
 		}
 		ret = 1;
 		break;
+	case SVM_VMGEXIT_SNP_CONFIG_INT_INJ:
+		svm->sev_es.hvdb_ai_vector = svm->vmcb->control.exit_info_1 & 0xff;
+		ret = 1;
+		break;
+	case SVM_VMGEXIT_SVSM_SPECIFIC_EOI: {
+		struct kvm_plane *target_plane;
+		struct kvm_vcpu *target_vcpu;
+		u8 vmpl = array_index_nospec((control->exit_info_1 >> 16) & 0xff,
+					       SVM_SEV_VMPL_MAX);
+		int vector = control->exit_info_1 & 0xff;
+
+		target_plane = vcpu->kvm->planes[vmpl];
+
+		if (target_plane) {
+			target_vcpu = plane_get_vcpu_by_id(target_plane, vcpu->vcpu_id);
+			if (target_vcpu)
+				kvm_ioapic_send_eoi(target_vcpu->arch.apic, vector);
+		}
+		ret = 1;
+		break;
+	}
 	case SVM_VMGEXIT_GET_APIC_IDS:
 		sev_get_apic_ids(svm);
 		ret = 1;
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 7aba2cceb44d..d2e397542a84 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -287,6 +287,7 @@ struct vcpu_sev_es_state {
 	bool snp_has_guest_vmsa;
 
 	gpa_t hvdb_gpa;
+	u8 hvdb_ai_vector;
 };
 
 struct vcpu_svm {
-- 
2.43.0