2023-01-23 22:53:26

by Tom Lendacky

Subject: [PATCH] crypto: ccp - Flush the SEV-ES TMR memory before giving it to firmware

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 <[email protected]>
---
drivers/crypto/ccp/sev-dev.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

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");

--
2.39.0

2023-02-03 05:05:02

by Herbert Xu

Subject: Re: [PATCH] crypto: ccp - Flush the SEV-ES TMR memory before giving it to firmware

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 <[email protected]>
> ---
> drivers/crypto/ccp/sev-dev.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)

Patch applied. Thanks.
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt