virt: tdx-guest: Refactor and streamline TDREPORT generation

Consolidate instances (code segments) of TDREPORT generation to improve
readability and maintainability, by refactoring each instance into invoking
a unified subroutine throughout the TDX guest driver. Implement proper
locking around TDG.MR.REPORT and TDG.MR.RTMR.EXTEND to avoid race inside
the TDX module. Preallocate TDREPORT buffer to reduce overhead in
subsequent TDREPORT generation.

Signed-off-by: Cedric Xing <cedric.xing@intel.com>
Acked-by: Dionna Amalie Glaze <dionnaglaze@google.com>
Link: https://patch.msgid.link/20250506-tdx-rtmr-v6-6-ac6ff5e9d58a@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Author: binxing

drivers/virt/coco/tdx-guest/tdx-guest.c

@@ -202,37 +202,8 @@ static u32 getquote_timeout = 30;
 
 static long tdx_get_report0(struct tdx_report_req __user *req)
 {
-	u8 *reportdata, *tdreport;
-	long ret;
-
-	reportdata = kmalloc(TDX_REPORTDATA_LEN, GFP_KERNEL);
-	if (!reportdata)
-		return -ENOMEM;
-
-	tdreport = kzalloc(TDX_REPORT_LEN, GFP_KERNEL);
-	if (!tdreport) {
-		ret = -ENOMEM;
-		goto out;
-	}
-
-	if (copy_from_user(reportdata, req->reportdata, TDX_REPORTDATA_LEN)) {
-		ret = -EFAULT;
-		goto out;
-	}
-
-	/* Generate TDREPORT0 using "TDG.MR.REPORT" TDCALL */
-	ret = tdx_mcall_get_report0(reportdata, tdreport);
-	if (ret)
-		goto out;
-
-	if (copy_to_user(req->tdreport, tdreport, TDX_REPORT_LEN))
-		ret = -EFAULT;
-
-out:
-	kfree(reportdata);
-	kfree(tdreport);
-
-	return ret;
+	return tdx_do_report(USER_SOCKPTR(req->reportdata),
+			     USER_SOCKPTR(req->tdreport));
 }
 
 static void free_quote_buf(void *buf)
@@ -293,7 +264,7 @@ static int wait_for_quote_completion(struct tdx_quote_buf *quote_buf, u32 timeou
 
 static int tdx_report_new(struct tsm_report *report, void *data)
 {
-	u8 *buf, *reportdata = NULL, *tdreport = NULL;
+	u8 *buf;
 	struct tdx_quote_buf *quote_buf = quote_data;
 	struct tsm_desc *desc = &report->desc;
 	int ret;
@@ -318,34 +289,16 @@ static int tdx_report_new(struct tsm_report *report, void *data)
 		goto done;
 	}
 
-	reportdata = kmalloc(TDX_REPORTDATA_LEN, GFP_KERNEL);
-	if (!reportdata) {
-		ret = -ENOMEM;
-		goto done;
-	}
-
-	tdreport = kzalloc(TDX_REPORT_LEN, GFP_KERNEL);
-	if (!tdreport) {
-		ret = -ENOMEM;
-		goto done;
-	}
-
-	memcpy(reportdata, desc->inblob, desc->inblob_len);
-
-	/* Generate TDREPORT0 using "TDG.MR.REPORT" TDCALL */
-	ret = tdx_mcall_get_report0(reportdata, tdreport);
-	if (ret) {
-		pr_err("GetReport call failed\n");
-		goto done;
-	}
-
 	memset(quote_data, 0, GET_QUOTE_BUF_SIZE);
 
 	/* Update Quote buffer header */
 	quote_buf->version = GET_QUOTE_CMD_VER;
 	quote_buf->in_len = TDX_REPORT_LEN;
 
-	memcpy(quote_buf->data, tdreport, TDX_REPORT_LEN);
+	ret = tdx_do_report(KERNEL_SOCKPTR(desc->inblob),
+			    KERNEL_SOCKPTR(quote_buf->data));
+	if (ret)
+		goto done;
 
 	err = tdx_hcall_get_quote(quote_data, GET_QUOTE_BUF_SIZE);
 	if (err) {
@@ -375,8 +328,6 @@ static int tdx_report_new(struct tsm_report *report, void *data)
 	 */
 done:
 	mutex_unlock(&quote_lock);
-	kfree(reportdata);
-	kfree(tdreport);
 
 	return ret;
 }