[PATCH] x86/sev-es: Use GHCB accessor for setting the MMIO scratch buffer

[PATCH] x86/sev-es: Use GHCB accessor for setting the MMIO scratch buffer

[Tom Lendacky]

From: Tom Lendacky <thomas.lendacky@amd.com>

Use ghcb_set_sw_scratch() to set the GHCB scratch field, which will also
set the corresponding bit in the GHCB valid_bitmap field.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
 arch/x86/kernel/sev-es.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c
index 6fcfdd32769f..4a96726fbaf8 100644
--- a/arch/x86/kernel/sev-es.c
+++ b/arch/x86/kernel/sev-es.c
@@ -751,7 +751,7 @@ static enum es_result vc_do_mmio(struct ghcb *ghcb, struct es_em_ctxt *ctxt,
 	/* Can never be greater than 8 */
 	exit_info_2 = bytes;
 
-	ghcb->save.sw_scratch = ghcb_pa + offsetof(struct ghcb, shared_buffer);
+	ghcb_set_sw_scratch(ghcb, ghcb_pa + offsetof(struct ghcb, shared_buffer));
 
 	return sev_es_ghcb_hv_call(ghcb, ctxt, exit_code, exit_info_1, exit_info_2);
 }
-- 
2.28.0

Re: [PATCH] x86/sev-es: Use GHCB accessor for setting the MMIO scratch buffer

[Joerg Roedel]

On Fri, Sep 25, 2020 at 08:38:26AM -0500, Tom Lendacky wrote:
> From: Tom Lendacky <thomas.lendacky@amd.com>
> 
> Use ghcb_set_sw_scratch() to set the GHCB scratch field, which will also
> set the corresponding bit in the GHCB valid_bitmap field.
> 
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
> ---
>  arch/x86/kernel/sev-es.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c
> index 6fcfdd32769f..4a96726fbaf8 100644
> --- a/arch/x86/kernel/sev-es.c
> +++ b/arch/x86/kernel/sev-es.c
> @@ -751,7 +751,7 @@ static enum es_result vc_do_mmio(struct ghcb *ghcb, struct es_em_ctxt *ctxt,
>  	/* Can never be greater than 8 */
>  	exit_info_2 = bytes;
>  
> -	ghcb->save.sw_scratch = ghcb_pa + offsetof(struct ghcb, shared_buffer);
> +	ghcb_set_sw_scratch(ghcb, ghcb_pa + offsetof(struct ghcb, shared_buffer));

Reviewed-by: Joerg Roedel <jroedel@suse.de>

Thanks for catching this!