From: Tom Lendacky <thomas.lendacky@amd.com>
Date: Mon, 23 Jan 2023 16:53:08 -0600
Subject: crypto: ccp - Flush the SEV-ES TMR memory before giving it to
 firmware
Git-commit: 46a334a98f585ef78d51d8f5736596887bdd7f54
Patch-mainline: v6.3-rc1
References: jsc#PED-7167

Perform a cache flush on the SEV-ES TMR memory after allocation to prevent
any possibility of the firmware encountering an error should dirty cache
lines be present. Use clflush_cache_range() to flush the SEV-ES TMR memory.

Fixes: 97f9ac3db661 ("crypto: ccp - Add support for SEV-ES to the PSP driver")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 drivers/crypto/ccp/sev-dev.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -26,6 +26,7 @@
 #include <linux/fs_struct.h>
 
 #include <asm/smp.h>
+#include <asm/cacheflush.h>
 
 #include "psp-dev.h"
 #include "sev-dev.h"
@@ -1334,7 +1335,10 @@ void sev_pci_init(void)
 
 	/* Obtain the TMR memory area for SEV-ES use */
 	sev_es_tmr = sev_fw_alloc(SEV_ES_TMR_SIZE);
-	if (!sev_es_tmr)
+	if (sev_es_tmr)
+		/* Must flush the cache before giving it to the firmware */
+		clflush_cache_range(sev_es_tmr, SEV_ES_TMR_SIZE);
+	else
 		dev_warn(sev->dev,
 			 "SEV: TMR allocation failed, SEV-ES support unavailable\n");