[PATCH v8 03/18] KVM: SVM: Add KVM_SEV_SEND_FINISH command

[Ashish Kalra <Ashish.Kalra@xxxxxxx>]

From: Brijesh Singh <Brijesh.Singh@xxxxxxx>

The command is used to finailize the encryption context created with
KVM_SEV_SEND_START command.

Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: "Radim Krčmář" <rkrcmar@xxxxxxxxxx>
Cc: Joerg Roedel <joro@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: Tom Lendacky <thomas.lendacky@xxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: kvm@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Reviewed-by: Steve Rutherford <srutherford@xxxxxxxxxx>
Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
Signed-off-by: Ashish Kalra <ashish.kalra@xxxxxxx>
---
 .../virt/kvm/amd-memory-encryption.rst        |  8 +++++++
 arch/x86/kvm/svm/sev.c                        | 23 +++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/Documentation/virt/kvm/amd-memory-encryption.rst b/Documentation/virt/kvm/amd-memory-encryption.rst
index d0dfa5b54e4f..93884ec8918e 100644
--- a/Documentation/virt/kvm/amd-memory-encryption.rst
+++ b/Documentation/virt/kvm/amd-memory-encryption.rst
@@ -314,6 +314,14 @@ Returns: 0 on success, -negative on error
                 __u32 trans_len;
         };
 
+12. KVM_SEV_SEND_FINISH
+------------------------
+
+After completion of the migration flow, the KVM_SEV_SEND_FINISH command can be
+issued by the hypervisor to delete the encryption context.
+
+Returns: 0 on success, -negative on error
+
 References
 ==========
 
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 7031b660f64d..4d3031c9fdcf 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -1153,6 +1153,26 @@ static int sev_send_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
 	return ret;
 }
 
+static int sev_send_finish(struct kvm *kvm, struct kvm_sev_cmd *argp)
+{
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+	struct sev_data_send_finish *data;
+	int ret;
+
+	if (!sev_guest(kvm))
+		return -ENOTTY;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->handle = sev->handle;
+	ret = sev_issue_cmd(kvm, SEV_CMD_SEND_FINISH, data, &argp->error);
+
+	kfree(data);
+	return ret;
+}
+
 int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
 {
 	struct kvm_sev_cmd sev_cmd;
@@ -1203,6 +1223,9 @@ int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
 	case KVM_SEV_SEND_UPDATE_DATA:
 		r = sev_send_update_data(kvm, &sev_cmd);
 		break;
+	case KVM_SEV_SEND_FINISH:
+		r = sev_send_finish(kvm, &sev_cmd);
+		break;
 	default:
 		r = -EINVAL;
 		goto out;
-- 
2.17.1