From mboxrd@z Thu Jan  1 00:00:00 1970
From: Keir Fraser <keir.xen@gmail.com>
Subject: Re: [PATCH] x86: convert BUG_ON()s to WARN_ON()s in
 read_descriptor()
Date: Fri, 16 Dec 2011 09:09:20 +0000
Message-ID: <CB10BB40.27633%keir.xen@gmail.com>
References: <4EE9D92A020000780006813A@nat28.tlf.novell.com>
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To: Jan Beulich <JBeulich@suse.com>, "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
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On 15/12/2011 10:25, "Jan Beulich" <JBeulich@suse.com> wrote:

> In the light of AMD erratum #700, and given that these checks happen
> for debugging purposes only and also only in debug builds of the
> hypervisor, make the failures non-fatal.

I think the changeset comment should have a brief description of erratum
#700. I also some reference should be made in a comment above the first
WARN_ON, explaining why they are now WARN_Ons (again, with reference to #700
and its symptoms).

Apart from that:
Acked-by: Keir Fraser <keir@xen.org>

> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> 
> --- a/xen/arch/x86/traps.c
> +++ b/xen/arch/x86/traps.c
> @@ -1544,11 +1544,11 @@ static int read_descriptor(unsigned int
>              asm volatile (
>                  "larl %2,%0 ; setz %1"
>                  : "=r" (a), "=qm" (valid) : "rm" (sel));
> -            BUG_ON(valid && ((a & 0x00f0ff00) != *ar));
> +            WARN_ON(valid && ((a & 0x00f0ff00) != *ar));
>              asm volatile (
>                  "lsll %2,%0 ; setz %1"
>                  : "=r" (l), "=qm" (valid) : "rm" (sel));
> -            BUG_ON(valid && (l != *limit));
> +            WARN_ON(valid && (l != *limit));
>          }
>  #endif
>      }
> 
> 
> 
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