[Part2 PATCH v4 23/29] KVM: SVM: Add support for SEV LAUNCH_SECRET command

[Brijesh Singh <brijesh.singh@xxxxxxx>]

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

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

Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
---
 arch/x86/kvm/svm.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 16b338d9dc87..dadfb8e15db9 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -6392,6 +6392,81 @@ static int sev_dbg_encrypt(struct kvm *kvm, struct kvm_sev_cmd *argp)
 	return sev_dbg_crypt(kvm, argp, false);
 }
 
+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(struct kvm_sev_launch_secret)))
+		return -EFAULT;
+
+	/* verify that request has a valid guest memory region and length */
+	if (!params.guest_uaddr ||
+	    !params.guest_len   ||
+	     (params.guest_len > SEV_FW_BLOB_MAX_SIZE))
+		return -EINVAL;
+
+	/* pin the guest memory region */
+	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 pinned memory pages are contiguous otherwise fail the 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;
+
+	/* copy the secret from userspace into a kernel buffer */
+	blob = 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;
+
+	/* copy the packet header from userspace into a kernel buffer */
+	hdr = 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 +6510,10 @@ static int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
 		r = sev_dbg_encrypt(kvm, &sev_cmd);
 		break;
 	}
+	case KVM_SEV_LAUNCH_SECRET: {
+		r = sev_launch_secret(kvm, &sev_cmd);
+		break;
+	}
 	default:
 		break;
 	}
-- 
2.9.5