diff mbox series

crypto: ccp - Flush the SEV-ES TMR memory before giving it to firmware

Message ID 9d112c35bf613a42453e05c69ec0c96a32ba6078.1674514388.git.thomas.lendacky@amd.com
State New
Headers
Series crypto: ccp - Flush the SEV-ES TMR memory before giving it to firmware |

Commit Message

Tom Lendacky Jan. 23, 2023, 10:53 p.m. UTC 
  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>
---
 drivers/crypto/ccp/sev-dev.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

Comments

Herbert Xu Feb. 3, 2023, 5:04 a.m. UTC | #1 
On Mon, Jan 23, 2023 at 04:53:08PM -0600, Tom Lendacky wrote:
> 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>
> ---
>  drivers/crypto/ccp/sev-dev.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)

Patch applied.  Thanks.
diff mbox series

Patch

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index 06fc7156c04f..04059b705db4 100644
--- 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"
@@ -1327,7 +1328,10 @@  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");