[PATCH v5 2/6] virt: tdx-guest: Give the Quote buffer an explicit type

[Peter Fang]

The Quote buffer is always a "struct tdx_quote_buf", but its global
pointer is a "void *". A function would have to convert it back to make
sense of it.

Declare the global with its actual type, and give it a better name.

This creates variable shadowing in wait_for_quote_completion(), so
rename its parameter for clarity.

AI was used under supervision to collect/apply feedback, review code and
workshop logs.

Signed-off-by: Peter Fang <peter.fang@xxxxxxxxx>
---
v5:
 - New patch. [Dave]
---
 drivers/virt/coco/tdx-guest/tdx-guest.c | 35 ++++++++++++-------------
 1 file changed, 17 insertions(+), 18 deletions(-)

diff --git a/drivers/virt/coco/tdx-guest/tdx-guest.c b/drivers/virt/coco/tdx-guest/tdx-guest.c
index d0303e31e816..896eb0a09c4a 100644
--- a/drivers/virt/coco/tdx-guest/tdx-guest.c
+++ b/drivers/virt/coco/tdx-guest/tdx-guest.c
@@ -192,7 +192,7 @@ struct tdx_quote_buf {
 };
 
 /* Quote data buffer */
-static void *quote_data;
+static struct tdx_quote_buf *quote_buf;
 
 /* Lock to streamline quote requests */
 static DEFINE_MUTEX(quote_lock);
@@ -209,7 +209,7 @@ static long tdx_get_report0(struct tdx_report_req __user *req)
 			     USER_SOCKPTR(req->tdreport));
 }
 
-static void free_quote_buf(void *buf)
+static void free_quote_buf(struct tdx_quote_buf *buf)
 {
 	size_t len = PAGE_ALIGN(GET_QUOTE_BUF_SIZE);
 	unsigned int count = len >> PAGE_SHIFT;
@@ -222,25 +222,25 @@ static void free_quote_buf(void *buf)
 	free_pages_exact(buf, len);
 }
 
-static void *alloc_quote_buf(void)
+static struct tdx_quote_buf *alloc_quote_buf(void)
 {
 	size_t len = PAGE_ALIGN(GET_QUOTE_BUF_SIZE);
 	unsigned int count = len >> PAGE_SHIFT;
-	void *addr;
+	struct tdx_quote_buf *buf;
 
-	addr = alloc_pages_exact(len, GFP_KERNEL | __GFP_ZERO);
-	if (!addr)
+	buf = alloc_pages_exact(len, GFP_KERNEL | __GFP_ZERO);
+	if (!buf)
 		return NULL;
 
-	if (set_memory_decrypted((unsigned long)addr, count))
+	if (set_memory_decrypted((unsigned long)buf, count))
 		return NULL;
 
-	return addr;
+	return buf;
 }
 
 /*
  * wait_for_quote_completion() - Wait for Quote request completion
- * @quote_buf: Address of Quote buffer.
+ * @buf: Address of Quote buffer.
  * @timeout: Timeout in seconds to wait for the Quote generation.
  *
  * As per TDX GHCI v1.0 specification, sec titled "TDG.VP.VMCALL<GetQuote>",
@@ -249,7 +249,7 @@ static void *alloc_quote_buf(void)
  * or error code after processing is complete. So wait till the status
  * changes from GET_QUOTE_IN_FLIGHT or the request being timed out.
  */
-static int wait_for_quote_completion(struct tdx_quote_buf *quote_buf, u32 timeout)
+static int wait_for_quote_completion(struct tdx_quote_buf *buf, u32 timeout)
 {
 	int i = 0;
 
@@ -257,7 +257,7 @@ static int wait_for_quote_completion(struct tdx_quote_buf *quote_buf, u32 timeou
 	 * Quote requests usually take a few seconds to complete, so waking up
 	 * once per second to recheck the status is fine for this use case.
 	 */
-	while (quote_buf->status == GET_QUOTE_IN_FLIGHT && i++ < timeout) {
+	while (buf->status == GET_QUOTE_IN_FLIGHT && i++ < timeout) {
 		if (msleep_interruptible(MSEC_PER_SEC))
 			return -EINTR;
 	}
@@ -268,7 +268,6 @@ static int wait_for_quote_completion(struct tdx_quote_buf *quote_buf, u32 timeou
 static int tdx_report_new_locked(struct tsm_report *report, void *data)
 {
 	u8 *buf;
-	struct tdx_quote_buf *quote_buf = quote_data;
 	struct tsm_report_desc *desc = &report->desc;
 	u32 out_len;
 	int ret;
@@ -285,7 +284,7 @@ static int tdx_report_new_locked(struct tsm_report *report, void *data)
 	if (desc->inblob_len != TDX_REPORTDATA_LEN)
 		return -EINVAL;
 
-	memset(quote_data, 0, GET_QUOTE_BUF_SIZE);
+	memset(quote_buf, 0, GET_QUOTE_BUF_SIZE);
 
 	/* Update Quote buffer header */
 	quote_buf->version = GET_QUOTE_CMD_VER;
@@ -296,7 +295,7 @@ static int tdx_report_new_locked(struct tsm_report *report, void *data)
 	if (ret)
 		return ret;
 
-	err = tdx_hcall_get_quote(quote_data, GET_QUOTE_BUF_SIZE);
+	err = tdx_hcall_get_quote(quote_buf, GET_QUOTE_BUF_SIZE);
 	if (err) {
 		pr_err("GetQuote hypercall failed, status:%llx\n", err);
 		return -EIO;
@@ -417,8 +416,8 @@ static int __init tdx_guest_init(void)
 	if (ret)
 		goto deinit_mr;
 
-	quote_data = alloc_quote_buf();
-	if (!quote_data) {
+	quote_buf = alloc_quote_buf();
+	if (!quote_buf) {
 		pr_err("Failed to allocate Quote buffer\n");
 		ret = -ENOMEM;
 		goto free_misc;
@@ -431,7 +430,7 @@ static int __init tdx_guest_init(void)
 	return 0;
 
 free_quote:
-	free_quote_buf(quote_data);
+	free_quote_buf(quote_buf);
 free_misc:
 	misc_deregister(&tdx_misc_dev);
 deinit_mr:
@@ -444,7 +443,7 @@ module_init(tdx_guest_init);
 static void __exit tdx_guest_exit(void)
 {
 	tsm_report_unregister(&tdx_tsm_ops);
-	free_quote_buf(quote_data);
+	free_quote_buf(quote_buf);
 	misc_deregister(&tdx_misc_dev);
 	tdx_mr_deinit(tdx_attr_groups[0]);
 }
-- 
2.53.0