Merge tag 'x86_sev_for_v6.12_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 SEV updates from Borislav Petkov:

 - A bunch of cleanups to the sev-guest driver. All in preparation for
   future SEV work

* tag 'x86_sev_for_v6.12_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  virt: sev-guest: Ensure the SNP guest messages do not exceed a page
  virt: sev-guest: Fix user-visible strings
  virt: sev-guest: Rename local guest message variables
  virt: sev-guest: Replace dev_dbg() with pr_debug()

2 files changed, 69 insertions, 65 deletions

diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 79bbe2be900e..ee34ab00a8d6 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -164,7 +164,7 @@ struct snp_guest_msg_hdr {
 
 struct snp_guest_msg {
 	struct snp_guest_msg_hdr hdr;
-	u8 payload[4000];
+	u8 payload[PAGE_SIZE - sizeof(struct snp_guest_msg_hdr)];
 } __packed;
 
 struct sev_guest_platform_data {
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index 6fc7884ea0a1..89754b019be2 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -114,7 +114,7 @@ static bool is_vmpck_empty(struct snp_guest_dev *snp_dev)
  */
 static void snp_disable_vmpck(struct snp_guest_dev *snp_dev)
 {
-	dev_alert(snp_dev->dev, "Disabling vmpck_id %d to prevent IV reuse.\n",
+	dev_alert(snp_dev->dev, "Disabling VMPCK%d communication key to prevent IV reuse.\n",
 		  vmpck_id);
 	memzero_explicit(snp_dev->vmpck, VMPCK_KEY_LEN);
 	snp_dev->vmpck = NULL;
@@ -291,44 +291,45 @@ static int dec_payload(struct snp_guest_dev *snp_dev, struct snp_guest_msg *msg,
 static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload, u32 sz)
 {
 	struct snp_guest_crypto *crypto = snp_dev->crypto;
-	struct snp_guest_msg *resp = &snp_dev->secret_response;
-	struct snp_guest_msg *req = &snp_dev->secret_request;
-	struct snp_guest_msg_hdr *req_hdr = &req->hdr;
-	struct snp_guest_msg_hdr *resp_hdr = &resp->hdr;
+	struct snp_guest_msg *resp_msg = &snp_dev->secret_response;
+	struct snp_guest_msg *req_msg = &snp_dev->secret_request;
+	struct snp_guest_msg_hdr *req_msg_hdr = &req_msg->hdr;
+	struct snp_guest_msg_hdr *resp_msg_hdr = &resp_msg->hdr;
 
-	dev_dbg(snp_dev->dev, "response [seqno %lld type %d version %d sz %d]\n",
-		resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version, resp_hdr->msg_sz);
+	pr_debug("response [seqno %lld type %d version %d sz %d]\n",
+		 resp_msg_hdr->msg_seqno, resp_msg_hdr->msg_type, resp_msg_hdr->msg_version,
+		 resp_msg_hdr->msg_sz);
 
 	/* Copy response from shared memory to encrypted memory. */
-	memcpy(resp, snp_dev->response, sizeof(*resp));
+	memcpy(resp_msg, snp_dev->response, sizeof(*resp_msg));
 
 	/* Verify that the sequence counter is incremented by 1 */
-	if (unlikely(resp_hdr->msg_seqno != (req_hdr->msg_seqno + 1)))
+	if (unlikely(resp_msg_hdr->msg_seqno != (req_msg_hdr->msg_seqno + 1)))
 		return -EBADMSG;
 
 	/* Verify response message type and version number. */
-	if (resp_hdr->msg_type != (req_hdr->msg_type + 1) ||
-	    resp_hdr->msg_version != req_hdr->msg_version)
+	if (resp_msg_hdr->msg_type != (req_msg_hdr->msg_type + 1) ||
+	    resp_msg_hdr->msg_version != req_msg_hdr->msg_version)
 		return -EBADMSG;
 
 	/*
 	 * If the message size is greater than our buffer length then return
 	 * an error.
 	 */
-	if (unlikely((resp_hdr->msg_sz + crypto->a_len) > sz))
+	if (unlikely((resp_msg_hdr->msg_sz + crypto->a_len) > sz))
 		return -EBADMSG;
 
 	/* Decrypt the payload */
-	return dec_payload(snp_dev, resp, payload, resp_hdr->msg_sz + crypto->a_len);
+	return dec_payload(snp_dev, resp_msg, payload, resp_msg_hdr->msg_sz + crypto->a_len);
 }
 
 static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8 type,
 			void *payload, size_t sz)
 {
-	struct snp_guest_msg *req = &snp_dev->secret_request;
-	struct snp_guest_msg_hdr *hdr = &req->hdr;
+	struct snp_guest_msg *msg = &snp_dev->secret_request;
+	struct snp_guest_msg_hdr *hdr = &msg->hdr;
 
-	memset(req, 0, sizeof(*req));
+	memset(msg, 0, sizeof(*msg));
 
 	hdr->algo = SNP_AEAD_AES_256_GCM;
 	hdr->hdr_version = MSG_HDR_VER;
@@ -343,10 +344,10 @@ static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8
 	if (!hdr->msg_seqno)
 		return -ENOSR;
 
-	dev_dbg(snp_dev->dev, "request [seqno %lld type %d version %d sz %d]\n",
-		hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz);
+	pr_debug("request [seqno %lld type %d version %d sz %d]\n",
+		 hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz);
 
-	return __enc_payload(snp_dev, req, payload, sz);
+	return __enc_payload(snp_dev, msg, payload, sz);
 }
 
 static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
@@ -495,8 +496,8 @@ struct snp_req_resp {
 static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
 {
 	struct snp_guest_crypto *crypto = snp_dev->crypto;
-	struct snp_report_req *req = &snp_dev->req.report;
-	struct snp_report_resp *resp;
+	struct snp_report_req *report_req = &snp_dev->req.report;
+	struct snp_report_resp *report_resp;
 	int rc, resp_len;
 
 	lockdep_assert_held(&snp_cmd_mutex);
@@ -504,7 +505,7 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
 	if (!arg->req_data || !arg->resp_data)
 		return -EINVAL;
 
-	if (copy_from_user(req, (void __user *)arg->req_data, sizeof(*req)))
+	if (copy_from_user(report_req, (void __user *)arg->req_data, sizeof(*report_req)))
 		return -EFAULT;
 
 	/*
@@ -512,30 +513,29 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
 	 * response payload. Make sure that it has enough space to cover the
 	 * authtag.
 	 */
-	resp_len = sizeof(resp->data) + crypto->a_len;
-	resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT);
-	if (!resp)
+	resp_len = sizeof(report_resp->data) + crypto->a_len;
+	report_resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT);
+	if (!report_resp)
 		return -ENOMEM;
 
-	rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg,
-				  SNP_MSG_REPORT_REQ, req, sizeof(*req), resp->data,
-				  resp_len);
+	rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg, SNP_MSG_REPORT_REQ,
+				  report_req, sizeof(*report_req), report_resp->data, resp_len);
 	if (rc)
 		goto e_free;
 
-	if (copy_to_user((void __user *)arg->resp_data, resp, sizeof(*resp)))
+	if (copy_to_user((void __user *)arg->resp_data, report_resp, sizeof(*report_resp)))
 		rc = -EFAULT;
 
 e_free:
-	kfree(resp);
+	kfree(report_resp);
 	return rc;
 }
 
 static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
 {
-	struct snp_derived_key_req *req = &snp_dev->req.derived_key;
+	struct snp_derived_key_req *derived_key_req = &snp_dev->req.derived_key;
 	struct snp_guest_crypto *crypto = snp_dev->crypto;
-	struct snp_derived_key_resp resp = {0};
+	struct snp_derived_key_resp derived_key_resp = {0};
 	int rc, resp_len;
 	/* Response data is 64 bytes and max authsize for GCM is 16 bytes. */
 	u8 buf[64 + 16];
@@ -550,25 +550,27 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque
 	 * response payload. Make sure that it has enough space to cover the
 	 * authtag.
 	 */
-	resp_len = sizeof(resp.data) + crypto->a_len;
+	resp_len = sizeof(derived_key_resp.data) + crypto->a_len;
 	if (sizeof(buf) < resp_len)
 		return -ENOMEM;
 
-	if (copy_from_user(req, (void __user *)arg->req_data, sizeof(*req)))
+	if (copy_from_user(derived_key_req, (void __user *)arg->req_data,
+			   sizeof(*derived_key_req)))
 		return -EFAULT;
 
-	rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg,
-				  SNP_MSG_KEY_REQ, req, sizeof(*req), buf, resp_len);
+	rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg, SNP_MSG_KEY_REQ,
+				  derived_key_req, sizeof(*derived_key_req), buf, resp_len);
 	if (rc)
 		return rc;
 
-	memcpy(resp.data, buf, sizeof(resp.data));
-	if (copy_to_user((void __user *)arg->resp_data, &resp, sizeof(resp)))
+	memcpy(derived_key_resp.data, buf, sizeof(derived_key_resp.data));
+	if (copy_to_user((void __user *)arg->resp_data, &derived_key_resp,
+			 sizeof(derived_key_resp)))
 		rc = -EFAULT;
 
 	/* The response buffer contains the sensitive data, explicitly clear it. */
 	memzero_explicit(buf, sizeof(buf));
-	memzero_explicit(&resp, sizeof(resp));
+	memzero_explicit(&derived_key_resp, sizeof(derived_key_resp));
 	return rc;
 }
 
@@ -576,9 +578,9 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
 			  struct snp_req_resp *io)
 
 {
-	struct snp_ext_report_req *req = &snp_dev->req.ext_report;
+	struct snp_ext_report_req *report_req = &snp_dev->req.ext_report;
 	struct snp_guest_crypto *crypto = snp_dev->crypto;
-	struct snp_report_resp *resp;
+	struct snp_report_resp *report_resp;
 	int ret, npages = 0, resp_len;
 	sockptr_t certs_address;
 
@@ -587,22 +589,22 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
 	if (sockptr_is_null(io->req_data) || sockptr_is_null(io->resp_data))
 		return -EINVAL;
 
-	if (copy_from_sockptr(req, io->req_data, sizeof(*req)))
+	if (copy_from_sockptr(report_req, io->req_data, sizeof(*report_req)))
 		return -EFAULT;
 
 	/* caller does not want certificate data */
-	if (!req->certs_len || !req->certs_address)
+	if (!report_req->certs_len || !report_req->certs_address)
 		goto cmd;
 
-	if (req->certs_len > SEV_FW_BLOB_MAX_SIZE ||
-	    !IS_ALIGNED(req->certs_len, PAGE_SIZE))
+	if (report_req->certs_len > SEV_FW_BLOB_MAX_SIZE ||
+	    !IS_ALIGNED(report_req->certs_len, PAGE_SIZE))
 		return -EINVAL;
 
 	if (sockptr_is_kernel(io->resp_data)) {
-		certs_address = KERNEL_SOCKPTR((void *)req->certs_address);
+		certs_address = KERNEL_SOCKPTR((void *)report_req->certs_address);
 	} else {
-		certs_address = USER_SOCKPTR((void __user *)req->certs_address);
-		if (!access_ok(certs_address.user, req->certs_len))
+		certs_address = USER_SOCKPTR((void __user *)report_req->certs_address);
+		if (!access_ok(certs_address.user, report_req->certs_len))
 			return -EFAULT;
 	}
 
@@ -612,45 +614,45 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
 	 * the host. If host does not supply any certs in it, then copy
 	 * zeros to indicate that certificate data was not provided.
 	 */
-	memset(snp_dev->certs_data, 0, req->certs_len);
-	npages = req->certs_len >> PAGE_SHIFT;
+	memset(snp_dev->certs_data, 0, report_req->certs_len);
+	npages = report_req->certs_len >> PAGE_SHIFT;
 cmd:
 	/*
 	 * The intermediate response buffer is used while decrypting the
 	 * response payload. Make sure that it has enough space to cover the
 	 * authtag.
 	 */
-	resp_len = sizeof(resp->data) + crypto->a_len;
-	resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT);
-	if (!resp)
+	resp_len = sizeof(report_resp->data) + crypto->a_len;
+	report_resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT);
+	if (!report_resp)
 		return -ENOMEM;
 
 	snp_dev->input.data_npages = npages;
-	ret = handle_guest_request(snp_dev, SVM_VMGEXIT_EXT_GUEST_REQUEST, arg,
-				   SNP_MSG_REPORT_REQ, &req->data,
-				   sizeof(req->data), resp->data, resp_len);
+	ret = handle_guest_request(snp_dev, SVM_VMGEXIT_EXT_GUEST_REQUEST, arg, SNP_MSG_REPORT_REQ,
+				   &report_req->data, sizeof(report_req->data),
+				   report_resp->data, resp_len);
 
 	/* If certs length is invalid then copy the returned length */
 	if (arg->vmm_error == SNP_GUEST_VMM_ERR_INVALID_LEN) {
-		req->certs_len = snp_dev->input.data_npages << PAGE_SHIFT;
+		report_req->certs_len = snp_dev->input.data_npages << PAGE_SHIFT;
 
-		if (copy_to_sockptr(io->req_data, req, sizeof(*req)))
+		if (copy_to_sockptr(io->req_data, report_req, sizeof(*report_req)))
 			ret = -EFAULT;
 	}
 
 	if (ret)
 		goto e_free;
 
-	if (npages && copy_to_sockptr(certs_address, snp_dev->certs_data, req->certs_len)) {
+	if (npages && copy_to_sockptr(certs_address, snp_dev->certs_data, report_req->certs_len)) {
 		ret = -EFAULT;
 		goto e_free;
 	}
 
-	if (copy_to_sockptr(io->resp_data, resp, sizeof(*resp)))
+	if (copy_to_sockptr(io->resp_data, report_resp, sizeof(*report_resp)))
 		ret = -EFAULT;
 
 e_free:
-	kfree(resp);
+	kfree(report_resp);
 	return ret;
 }
 
@@ -1090,6 +1092,8 @@ static int __init sev_guest_probe(struct platform_device *pdev)
 	void __iomem *mapping;
 	int ret;
 
+	BUILD_BUG_ON(sizeof(struct snp_guest_msg) > PAGE_SIZE);
+
 	if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
 		return -ENODEV;
 
@@ -1115,13 +1119,13 @@ static int __init sev_guest_probe(struct platform_device *pdev)
 	ret = -EINVAL;
 	snp_dev->vmpck = get_vmpck(vmpck_id, secrets, &snp_dev->os_area_msg_seqno);
 	if (!snp_dev->vmpck) {
-		dev_err(dev, "invalid vmpck id %d\n", vmpck_id);
+		dev_err(dev, "Invalid VMPCK%d communication key\n", vmpck_id);
 		goto e_unmap;
 	}
 
 	/* Verify that VMPCK is not zero. */
 	if (is_vmpck_empty(snp_dev)) {
-		dev_err(dev, "vmpck id %d is null\n", vmpck_id);
+		dev_err(dev, "Empty VMPCK%d communication key\n", vmpck_id);
 		goto e_unmap;
 	}
 
@@ -1172,7 +1176,7 @@ static int __init sev_guest_probe(struct platform_device *pdev)
 	if (ret)
 		goto e_free_cert_data;
 
-	dev_info(dev, "Initialized SEV guest driver (using vmpck_id %d)\n", vmpck_id);
+	dev_info(dev, "Initialized SEV guest driver (using VMPCK%d communication key)\n", vmpck_id);
 	return 0;
 
 e_free_cert_data: