KVM: SVM: Add support for SEV LAUNCH_SECRET command

The command is used for injecting a secret into the guest memory region.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86@kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Borislav Petkov <bp@suse.de>

arch/x86/kvm/svm.c

@@ -6397,6 +6397,71 @@ static int sev_dbg_crypt(struct kvm *kvm, struct kvm_sev_cmd *argp, bool dec)
 	return ret;
 }
 
+static int sev_launch_secret(struct kvm *kvm, struct kvm_sev_cmd *argp)
+{
+	struct kvm_sev_info *sev = &kvm->arch.sev_info;
+	struct sev_data_launch_secret *data;
+	struct kvm_sev_launch_secret params;
+	struct page **pages;
+	void *blob, *hdr;
+	unsigned long n;
+	int ret;
+
+	if (!sev_guest(kvm))
+		return -ENOTTY;
+
+	if (copy_from_user(&params, (void __user *)(uintptr_t)argp->data, sizeof(params)))
+		return -EFAULT;
+
+	pages = sev_pin_memory(kvm, params.guest_uaddr, params.guest_len, &n, 1);
+	if (!pages)
+		return -ENOMEM;
+
+	/*
+	 * The secret must be copied into contiguous memory region, lets verify
+	 * that userspace memory pages are contiguous before we issue command.
+	 */
+	if (get_num_contig_pages(0, pages, n) != n) {
+		ret = -EINVAL;
+		goto e_unpin_memory;
+	}
+
+	ret = -ENOMEM;
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		goto e_unpin_memory;
+
+	blob = psp_copy_user_blob(params.trans_uaddr, params.trans_len);
+	if (IS_ERR(blob)) {
+		ret = PTR_ERR(blob);
+		goto e_free;
+	}
+
+	data->trans_address = __psp_pa(blob);
+	data->trans_len = params.trans_len;
+
+	hdr = psp_copy_user_blob(params.hdr_uaddr, params.hdr_len);
+	if (IS_ERR(hdr)) {
+		ret = PTR_ERR(hdr);
+		goto e_free_blob;
+	}
+	data->trans_address = __psp_pa(blob);
+	data->trans_len = params.trans_len;
+
+	data->handle = sev->handle;
+	ret = sev_issue_cmd(kvm, SEV_CMD_LAUNCH_UPDATE_SECRET, data, &argp->error);
+
+	kfree(hdr);
+
+e_free_blob:
+	kfree(blob);
+e_free:
+	kfree(data);
+e_unpin_memory:
+	sev_unpin_memory(kvm, pages, n);
+	return ret;
+}
+
 static int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
 {
 	struct kvm_sev_cmd sev_cmd;
@@ -6435,6 +6500,9 @@ static int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
 	case KVM_SEV_DBG_ENCRYPT:
 		r = sev_dbg_crypt(kvm, &sev_cmd, false);
 		break;
+	case KVM_SEV_LAUNCH_SECRET:
+		r = sev_launch_secret(kvm, &sev_cmd);
+		break;
 	default:
 		r = -EINVAL;
 		goto out;