[PATCH] x86/sev: Fix __reserved field in sev_config

[PATCH] x86/sev: Fix __reserved field in sev_config

[Pavan Kumar Paluri]

sev_config currently has debug, ghcbs_initialized, and use_cas fields.
However, __reserved count has not been updated. Fix this.

Fixes: 34ff65901735 ("x86/sev: Use kernel provided SVSM Calling Areas")
Cc: stable@vger.kernel.org
Signed-off-by: Pavan Kumar Paluri <papaluri@amd.com>
---
 arch/x86/coco/sev/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c
index 082d61d85dfc..de1df0cb45da 100644
--- a/arch/x86/coco/sev/core.c
+++ b/arch/x86/coco/sev/core.c
@@ -163,7 +163,7 @@ struct sev_config {
 	       */
 	      use_cas		: 1,
 
-	      __reserved	: 62;
+	      __reserved	: 61;
 };
 
 static struct sev_config sev_cfg __read_mostly;
-- 
2.34.1

Re: [PATCH] x86/sev: Fix __reserved field in sev_config

[Borislav Petkov]

On Mon, Jul 29, 2024 at 01:08:08PM -0500, Pavan Kumar Paluri wrote:
> sev_config currently has debug, ghcbs_initialized, and use_cas fields.
> However, __reserved count has not been updated. Fix this.
> 
> Fixes: 34ff65901735 ("x86/sev: Use kernel provided SVSM Calling Areas")
> Cc: stable@vger.kernel.org

stable because?


-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

Re: [PATCH] x86/sev: Fix __reserved field in sev_config

[Paluri, PavanKumar]

Hi Boris,

On 7/29/2024 2:32 PM, Borislav Petkov wrote:
> On Mon, Jul 29, 2024 at 01:08:08PM -0500, Pavan Kumar Paluri wrote:
>> sev_config currently has debug, ghcbs_initialized, and use_cas fields.
>> However, __reserved count has not been updated. Fix this.
>>
>> Fixes: 34ff65901735 ("x86/sev: Use kernel provided SVSM Calling Areas")
>> Cc: stable@vger.kernel.org
> 
> stable because?
> 

Thanks for noticing this.

I shall remove Cc tag since:
1. The commit that introduced the bug is only part of 6.11-rc1. So there
is no stable kernel fix needed here.
2. An incorrect __reserved field did not cause any hang/data corruption
or a build-error.

I will re-spin a v2.

Thanks,
Pavan
> 

Re: [PATCH] x86/sev: Fix __reserved field in sev_config

[Borislav Petkov]

On Mon, Jul 29, 2024 at 06:45:21PM -0500, Paluri, PavanKumar wrote:
> I will re-spin a v2.

You don't have to - I'll fix it up.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

[tip: x86/urgent] x86/sev: Fix __reserved field in sev_config

[tip-bot2 for Pavan Kumar Paluri]

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     c14e4114582c20276467226387d5bae7310a849e
Gitweb:        https://git.kernel.org/tip/c14e4114582c20276467226387d5bae7310a849e
Author:        Pavan Kumar Paluri <papaluri@amd.com>
AuthorDate:    Mon, 29 Jul 2024 13:08:08 -05:00
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Tue, 30 Jul 2024 10:07:26 +02:00

x86/sev: Fix __reserved field in sev_config

sev_config currently has debug, ghcbs_initialized, and use_cas fields.
However, __reserved count has not been updated. Fix this.

Fixes: 34ff65901735 ("x86/sev: Use kernel provided SVSM Calling Areas")
Signed-off-by: Pavan Kumar Paluri <papaluri@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240729180808.366587-1-papaluri@amd.com
---
 arch/x86/coco/sev/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c
index 082d61d..de1df0c 100644
--- a/arch/x86/coco/sev/core.c
+++ b/arch/x86/coco/sev/core.c
@@ -163,7 +163,7 @@ struct sev_config {
 	       */
 	      use_cas		: 1,
 
-	      __reserved	: 62;
+	      __reserved	: 61;
 };
 
 static struct sev_config sev_cfg __read_mostly;

Re: [PATCH] x86/sev: Fix __reserved field in sev_config

[Tom Lendacky]

On 7/29/24 13:08, Pavan Kumar Paluri wrote:
> sev_config currently has debug, ghcbs_initialized, and use_cas fields.
> However, __reserved count has not been updated. Fix this.
> 
> Fixes: 34ff65901735 ("x86/sev: Use kernel provided SVSM Calling Areas")
> Cc: stable@vger.kernel.org
> Signed-off-by: Pavan Kumar Paluri <papaluri@amd.com>

Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>

You'd think the compiler would spit out some kind of warning when this
happens, but I guess it just happily adds another u64 to the struct.

Thanks,
Tom

> ---
>  arch/x86/coco/sev/core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c
> index 082d61d85dfc..de1df0cb45da 100644
> --- a/arch/x86/coco/sev/core.c
> +++ b/arch/x86/coco/sev/core.c
> @@ -163,7 +163,7 @@ struct sev_config {
>  	       */
>  	      use_cas		: 1,
>  
> -	      __reserved	: 62;
> +	      __reserved	: 61;
>  };
>  
>  static struct sev_config sev_cfg __read_mostly;