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 <thomas.lendacky@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index 13f1c88810d8f4bdaee9fbedab40183f0a0c9708..e2f25926eb514e477f92eac95bb7d54a4eb834b1 100644 (file)
--- 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"
@@ -1335,7 +1336,10 @@ 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");