[PATCH 6/7] KVM: SVM: Add support for the SEV-SNP #HV IPI NAE event

[Melody Wang <huibo.wang@amd.com>]

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@amd.com>
Signed-off-by: Thomas Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Melody Wang <huibo.wang@amd.com>
---
 arch/x86/include/uapi/asm/svm.h |  1 +
 arch/x86/kvm/lapic.c            | 24 +++++++++++++++++++++++-
 arch/x86/kvm/lapic.h            |  2 ++
 arch/x86/kvm/svm/sev.c          | 26 ++++++++++++++++++++++++++
 4 files changed, 52 insertions(+), 1 deletion(-)

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 e3ec4d8607c1..9601d960824f 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2556,7 +2556,7 @@ static int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
 static int apic_mmio_write(struct kvm_vcpu *vcpu, struct kvm_io_device *this,
 			    gpa_t address, int len, const void *data)
 {
-	struct kvm_lapic *apic = to_lapic(this);
+	struct kvm_lapic *apic = this ? to_lapic(this) : vcpu->arch.apic;
 	unsigned int offset = address - apic->base_address;
 	u32 val;
 
@@ -3581,3 +3581,25 @@ void kvm_lapic_exit(void)
 	static_key_deferred_flush(&apic_sw_disabled);
 	WARN_ON(static_branch_unlikely(&apic_sw_disabled.key));
 }
+
+/* Send IPI by writing ICR with MSR write when X2APIC enabled, with mmio write when XAPIC enabled */
+int kvm_xapic_x2apic_send_ipi(struct kvm_vcpu *vcpu, u64 data)
+{
+	u32 icr_msr_addr = APIC_BASE_MSR + (APIC_ICR >> 4);
+	struct kvm_lapic *apic = vcpu->arch.apic;
+	gpa_t gpa = apic->base_address + APIC_ICR;
+
+	if (!kvm_lapic_enabled(vcpu))
+		return 1;
+
+	if (vcpu->arch.apic_base & X2APIC_ENABLE) {
+		if (!kvm_x2apic_msr_write(vcpu, icr_msr_addr, data))
+			return 0;
+	} else {
+		if (!apic_mmio_write(vcpu, NULL, gpa, 4, &data))
+			return 0;
+	}
+
+	return 1;
+}
+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 274885af4ebc..afd440c88981 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -156,6 +156,8 @@ 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_lapic_readable_reg_mask(struct kvm_lapic *apic);
 
 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 2483357bdd97..95ee199e38fb 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -35,6 +35,7 @@
 #include "svm_ops.h"
 #include "cpuid.h"
 #include "trace.h"
+#include "lapic.h"
 
 #define GHCB_VERSION_MAX	2ULL
 #define GHCB_VERSION_MIN	1ULL
@@ -3554,6 +3555,7 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
 			goto vmgexit_err;
 		break;
 	case SVM_VMGEXIT_HVDB_PAGE:
+	case SVM_VMGEXIT_HV_IPI:
 		if (!is_sev_snp_guest(vcpu))
 			goto vmgexit_err;
 		break;
@@ -4362,6 +4364,22 @@ 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;
@@ -4635,6 +4653,14 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
 			ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, GHCB_ERR_INVALID_INPUT);
 		}
 
+		ret = 1;
+		break;
+	case SVM_VMGEXIT_HV_IPI:
+		if (sev_snp_hv_ipi(svm)) {
+			ghcb_set_sw_exit_info_1(svm->sev_es.ghcb, 2);
+			ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, GHCB_ERR_INVALID_INPUT);
+		}
+
 		ret = 1;
 		break;
 	case SVM_VMGEXIT_UNSUPPORTED_EVENT:
-- 
2.43.0