[RFC PATCH v5 7/8] KVM: SVM: Add support for the SEV-SNP #HV IPI NAE event

[Melody Wang]

The #HV IPI NAE event allows the guest to send an IPI to other vCPUs in
the guest when Restricted Injection is enabled. Implement the NAE event
as per GHCB specification.

Co-developed-by: Thomas Lendacky <thomas.lendacky@xxxxxxx>
Signed-off-by: Thomas Lendacky <thomas.lendacky@xxxxxxx>
Signed-off-by: Melody Wang <huibo.wang@xxxxxxx>
---
 arch/x86/include/uapi/asm/svm.h |  1 +
 arch/x86/kvm/lapic.c            | 12 ++++++++++++
 arch/x86/kvm/lapic.h            |  2 ++
 arch/x86/kvm/svm/sev.c          | 21 +++++++++++++++++++++
 4 files changed, 36 insertions(+)

diff --git a/arch/x86/include/uapi/asm/svm.h b/arch/x86/include/uapi/asm/svm.h
index d84a13ac4627..1c0165e9db16 100644
--- a/arch/x86/include/uapi/asm/svm.h
+++ b/arch/x86/include/uapi/asm/svm.h
@@ -122,6 +122,7 @@
 #define SVM_VMGEXIT_HVDB_SET			1
 #define SVM_VMGEXIT_HVDB_QUERY			2
 #define SVM_VMGEXIT_HVDB_CLEAR			3
+#define SVM_VMGEXIT_HV_IPI			0x80000015ull
 #define SVM_VMGEXIT_SNP_RUN_VMPL		0x80000018ull
 #define SVM_VMGEXIT_SAVIC			0x8000001aull
 #define SVM_VMGEXIT_SAVIC_REGISTER_GPA		0
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 037a4599d6f1..3a83bdd13b5a 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -3673,3 +3673,15 @@ void kvm_lapic_exit(void)
 	static_key_deferred_flush(&apic_sw_disabled);
 	WARN_ON(static_branch_unlikely(&apic_sw_disabled.key));
 }
+
+int kvm_xapic_x2apic_send_ipi(struct kvm_vcpu *vcpu, u64 data)
+{
+	struct kvm_lapic *apic = vcpu->arch.apic;
+
+	if (!kvm_lapic_enabled(vcpu))
+		return 1;
+
+	kvm_apic_send_ipi(apic, (u32)data, (u32)(data >> 32));
+	return 0;
+}
+EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_xapic_x2apic_send_ipi);
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index 8530a6333bdd..e5e6730bfcca 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -194,6 +194,8 @@ int kvm_hv_vapic_msr_read(struct kvm_vcpu *vcpu, u32 msr, u64 *data);
 int kvm_lapic_set_pv_eoi(struct kvm_vcpu *vcpu, u64 data, unsigned long len);
 void kvm_lapic_exit(void);
 
+int kvm_xapic_x2apic_send_ipi(struct kvm_vcpu *vcpu, u64 data);
+
 u64 kvm_x2apic_disable_read_intercept_reg_mask(struct kvm_vcpu *vcpu);
 
 static inline void kvm_lapic_set_irr(int vec, struct kvm_lapic *apic)
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 9aafa6167ae6..b7c2993f8c63 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -4414,6 +4414,22 @@ static int sev_snp_hv_doorbell_page(struct vcpu_svm *svm)
 	return 0;
 }
 
+static int sev_snp_hv_ipi(struct vcpu_svm *svm)
+{
+	struct kvm_vcpu *vcpu = &svm->vcpu;
+	u64 icr_info;
+
+	if (!is_sev_snp_guest(vcpu))
+		return -EINVAL;
+
+	icr_info = svm->vmcb->control.exit_info_1;
+
+	if (kvm_xapic_x2apic_send_ipi(vcpu, icr_info))
+		return -EINVAL;
+
+	return 0;
+}
+
 static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm)
 {
 	struct vmcb_control_area *control = &svm->vmcb->control;
@@ -4566,6 +4582,7 @@ static bool is_snp_only_vmgexit(u64 exit_code)
 	case SVM_VMGEXIT_EXT_GUEST_REQUEST:
 	case SVM_VMGEXIT_PSC:
 	case SVM_VMGEXIT_HVDB_PAGE:
+	case SVM_VMGEXIT_HV_IPI:
 		return true;
 	default:
 		return false;
@@ -4754,6 +4771,10 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
 			svm_vmgexit_bad_input(svm, GHCB_ERR_INVALID_INPUT);
 
 		return 1;
+	case SVM_VMGEXIT_HV_IPI:
+		if (sev_snp_hv_ipi(svm))
+			svm_vmgexit_bad_input(svm, GHCB_ERR_INVALID_INPUT);
+		return 1;
 	case SVM_VMGEXIT_UNSUPPORTED_EVENT:
 		/*
 		 * Note, the _guest_ is reporting an unsupported #VC, i.e. this
-- 
2.43.0