Patch "crypto: ccp - Avoid discarding errors in psp_send_platform_access_msg()" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    crypto: ccp - Avoid discarding errors in psp_send_platform_access_msg()

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     crypto-ccp-avoid-discarding-errors-in-psp_send_platf.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit df605f7dd85a9df1f9545e9cd1d65d81eac98773
Author: Mario Limonciello <mario.limonciello@xxxxxxx>
Date:   Tue Feb 13 11:34:28 2024 -0600

    crypto: ccp - Avoid discarding errors in psp_send_platform_access_msg()
    
    [ Upstream commit 0e8fca2f12ceb77c3a6b6f210135031f264aa612 ]
    
    Errors can potentially occur in the "processing" of PSP commands or
    commands can be processed successfully but still return an error code in
    the header.
    
    This second case was being discarded because PSP communication worked but
    the command returned an error code in the payload header.
    
    Capture both cases and return them to the caller as -EIO for the caller
    to investigate. The caller can detect the latter by looking at
    `req->header->status`.
    
    Reported-and-tested-by: Tim Van Patten <timvp@xxxxxxxxxx>
    Fixes: 7ccc4f4e2e50 ("crypto: ccp - Add support for an interface for platform features")
    Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
    Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/crypto/ccp/platform-access.c b/drivers/crypto/ccp/platform-access.c
index 94367bc49e35b..1b8ed33897332 100644
--- a/drivers/crypto/ccp/platform-access.c
+++ b/drivers/crypto/ccp/platform-access.c
@@ -118,9 +118,16 @@ int psp_send_platform_access_msg(enum psp_platform_access_msg msg,
 		goto unlock;
 	}
 
-	/* Store the status in request header for caller to investigate */
+	/*
+	 * Read status from PSP. If status is non-zero, it indicates an error
+	 * occurred during "processing" of the command.
+	 * If status is zero, it indicates the command was "processed"
+	 * successfully, but the result of the command is in the payload.
+	 * Return both cases to the caller as -EIO to investigate.
+	 */
 	cmd_reg = ioread32(cmd);
-	req->header.status = FIELD_GET(PSP_CMDRESP_STS, cmd_reg);
+	if (FIELD_GET(PSP_CMDRESP_STS, cmd_reg))
+		req->header.status = FIELD_GET(PSP_CMDRESP_STS, cmd_reg);
 	if (req->header.status) {
 		ret = -EIO;
 		goto unlock;