Re: [PATCH 1/2] Livepatch: resolve old address before function verification

[Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>]

> From: Bjoern Doebel <doebel@xxxxxxxxx>
> Sent: Monday, March 7, 2022 11:53 AM
> To: xen-devel@xxxxxxxxxxxxxxxxxxxx <xen-devel@xxxxxxxxxxxxxxxxxxxx>
> Cc: Michael Kurth <mku@xxxxxxxxx>; Martin Pohlack <mpohlack@xxxxxxxxx>; Roger 
> Pau Monne <roger.pau@xxxxxxxxxx>; Andrew Cooper <Andrew.Cooper3@xxxxxxxxxx>; 
> Bjoern Doebel <doebel@xxxxxxxxx>; Konrad Rzeszutek Wilk 
> <konrad.wilk@xxxxxxxxxx>; Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
> Subject: [PATCH 1/2] Livepatch: resolve old address before function 
> verification 
>  
> When verifying that a livepatch can be applied, we may as well want to
> inspect the target function to be patched. To do so, we need to resolve
> this function's address before running the arch-specific
> livepatch_verify hook.
> 
> Signed-off-by: Bjoern Doebel <doebel@xxxxxxxxx>
> CC: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> CC: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
> ---
>  xen/common/livepatch.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/xen/common/livepatch.c b/xen/common/livepatch.c
> index ec301a9f12..be2cf75c2d 100644
> --- a/xen/common/livepatch.c
> +++ b/xen/common/livepatch.c
> @@ -684,11 +684,11 @@ static int prepare_payload(struct payload *payload,
>                  return -EINVAL;
>              }
>  
> -            rc = arch_livepatch_verify_func(f);
> +            rc = resolve_old_address(f, elf);
>              if ( rc )
>                  return rc;
>  
> -            rc = resolve_old_address(f, elf);
> +            rc = arch_livepatch_verify_func(f);
>              if ( rc )
>                  return rc;
>  
> -- 
> 2.32.0

Reviewed-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>