lkml.org 
[lkml]   [2021]   [Feb]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] x86/sev-es: Remove subtraction of res variable
On Tue, Feb 23, 2021 at 12:11:30PM +0100, Borislav Petkov wrote:
> From: Borislav Petkov <bp@suse.de>
>
> vc_decode_insn() calls copy_from_kernel_nofault() by way of
> vc_fetch_insn_kernel() to fetch 15 bytes max of opcodes to decode.
>
> copy_from_kernel_nofault() returns negative on error and 0 on success.
> The error case is handled by returning ES_EXCEPTION.
>
> In the success case, the ret variable which contains the return value is
> 0 so there's no need to subtract it from MAX_INSN_SIZE when initializing
> the insn buffer for further decoding. Remove it.
>
> No functional changes.
>
> Signed-off-by: Borislav Petkov <bp@suse.de>

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

> ---
> 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 84c1821819af..1e78f4bd7bf2 100644
> --- a/arch/x86/kernel/sev-es.c
> +++ b/arch/x86/kernel/sev-es.c
> @@ -267,7 +267,7 @@ static enum es_result vc_decode_insn(struct es_em_ctxt *ctxt)
> return ES_EXCEPTION;
> }
>
> - insn_init(&ctxt->insn, buffer, MAX_INSN_SIZE - res, 1);
> + insn_init(&ctxt->insn, buffer, MAX_INSN_SIZE, 1);
> insn_get_length(&ctxt->insn);
> }
>
> --
> 2.29.2

\
 
 \ /
  Last update: 2021-02-23 13:26    [W:0.038 / U:1.616 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site