2021-03-04 13:15:40

by Tom Lendacky

Subject: [PATCH] crypto: ccp - Don't initialize SEV support without the SEV feature

From: Tom Lendacky <[email protected]>

If SEV has been disabled (e.g. through BIOS), the driver probe will still
issue SEV firmware commands. The SEV INIT firmware command will return an
error in this situation, but the error code is a general error code that
doesn't highlight the exact reason.

Add a check for X86_FEATURE_SEV in sev_dev_init() and emit a meaningful
message and skip attempting to initialize the SEV firmware if the feature
is not enabled. Since building the SEV code is dependent on X86_64, adding
the check won't cause any build problems.

Cc: John Allen <[email protected]>
Cc: Brijesh Singh <[email protected]>
Signed-off-by: Tom Lendacky <[email protected]>
---
drivers/crypto/ccp/sev-dev.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index 476113e12489..b9fc8d7aca73 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -21,6 +21,7 @@
#include <linux/ccp.h>
#include <linux/firmware.h>
#include <linux/gfp.h>
+#include <linux/cpufeature.h>

#include <asm/smp.h>

@@ -971,6 +972,11 @@ int sev_dev_init(struct psp_device *psp)
struct sev_device *sev;
int ret = -ENOMEM;

+ if (!boot_cpu_has(X86_FEATURE_SEV)) {
+ dev_info_once(dev, "SEV: memory encryption not enabled by BIOS\n");
+ return 0;
+ }
+
sev = devm_kzalloc(dev, sizeof(*sev), GFP_KERNEL);
if (!sev)
goto e_err;
--
2.30.0

2021-03-05 01:03:42

by Brijesh Singh

Subject: Re: [PATCH] crypto: ccp - Don't initialize SEV support without the SEV feature

On 3/3/21 4:31 PM, Tom Lendacky wrote:
> From: Tom Lendacky <[email protected]>
>
> If SEV has been disabled (e.g. through BIOS), the driver probe will still
> issue SEV firmware commands. The SEV INIT firmware command will return an
> error in this situation, but the error code is a general error code that
> doesn't highlight the exact reason.
>
> Add a check for X86_FEATURE_SEV in sev_dev_init() and emit a meaningful
> message and skip attempting to initialize the SEV firmware if the feature
> is not enabled. Since building the SEV code is dependent on X86_64, adding
> the check won't cause any build problems.
>
> Cc: John Allen <[email protected]>
> Cc: Brijesh Singh <[email protected]>
> Signed-off-by: Tom Lendacky <[email protected]>


Reviewed-By: Brijesh Singh <[email protected]>

> ---
> drivers/crypto/ccp/sev-dev.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
> index 476113e12489..b9fc8d7aca73 100644
> --- a/drivers/crypto/ccp/sev-dev.c
> +++ b/drivers/crypto/ccp/sev-dev.c
> @@ -21,6 +21,7 @@
> #include <linux/ccp.h>
> #include <linux/firmware.h>
> #include <linux/gfp.h>
> +#include <linux/cpufeature.h>
>
> #include <asm/smp.h>
>
> @@ -971,6 +972,11 @@ int sev_dev_init(struct psp_device *psp)
> struct sev_device *sev;
> int ret = -ENOMEM;
>
> + if (!boot_cpu_has(X86_FEATURE_SEV)) {
> + dev_info_once(dev, "SEV: memory encryption not enabled by BIOS\n");
> + return 0;
> + }
> +
> sev = devm_kzalloc(dev, sizeof(*sev), GFP_KERNEL);
> if (!sev)
> goto e_err;

2021-03-12 13:14:47

by Herbert Xu

Subject: Re: [PATCH] crypto: ccp - Don't initialize SEV support without the SEV feature

On Wed, Mar 03, 2021 at 04:31:09PM -0600, Tom Lendacky wrote:
> From: Tom Lendacky <[email protected]>
>
> If SEV has been disabled (e.g. through BIOS), the driver probe will still
> issue SEV firmware commands. The SEV INIT firmware command will return an
> error in this situation, but the error code is a general error code that
> doesn't highlight the exact reason.
>
> Add a check for X86_FEATURE_SEV in sev_dev_init() and emit a meaningful
> message and skip attempting to initialize the SEV firmware if the feature
> is not enabled. Since building the SEV code is dependent on X86_64, adding
> the check won't cause any build problems.
>
> Cc: John Allen <[email protected]>
> Cc: Brijesh Singh <[email protected]>
> Signed-off-by: Tom Lendacky <[email protected]>
> ---
> drivers/crypto/ccp/sev-dev.c | 6 ++++++
> 1 file changed, 6 insertions(+)

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