x86/hvm: Correct error message in check_segment()

[PATCH] x86/hvm: Correct error message in check_segment()

Posted by Andrew Cooper 3 years, 6 months ago

The error message is wrong (given AMD's older interpretation of what a NUL
segment should contain, attribute wise), and actively unhelpful because you
only get it in response to a hypercall where the one piece of information you
cannot provide is the segment selector.

Fix the message to talk about segment attributes, rather than the selector.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
CC: Wei Liu <wl@xen.org>
---
 xen/arch/x86/hvm/domain.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/arch/x86/hvm/domain.c b/xen/arch/x86/hvm/domain.c
index 8e3375265c..ffe952c2df 100644
--- a/xen/arch/x86/hvm/domain.c
+++ b/xen/arch/x86/hvm/domain.c
@@ -39,7 +39,7 @@ static int check_segment(struct segment_register *reg, enum x86_segment seg)
     {
         if ( seg != x86_seg_ds && seg != x86_seg_es )
         {
-            gprintk(XENLOG_ERR, "Null selector provided for CS, SS or TR\n");
+            gprintk(XENLOG_ERR, "Empty segment attributes for CS, SS or TR\n");
             return -EINVAL;
         }
         return 0;
-- 
2.11.0

Re: [PATCH] x86/hvm: Correct error message in check_segment()

Posted by Jan Beulich 3 years, 6 months ago

On 02.10.2020 13:30, Andrew Cooper wrote:
> The error message is wrong (given AMD's older interpretation of what a NUL
> segment should contain, attribute wise), and actively unhelpful because you
> only get it in response to a hypercall where the one piece of information you
> cannot provide is the segment selector.
> 
> Fix the message to talk about segment attributes, rather than the selector.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

Acked-by: Jan Beulich <jbeulich@suse.com>
albeit ...

> --- a/xen/arch/x86/hvm/domain.c
> +++ b/xen/arch/x86/hvm/domain.c
> @@ -39,7 +39,7 @@ static int check_segment(struct segment_register *reg, enum x86_segment seg)
>      {
>          if ( seg != x86_seg_ds && seg != x86_seg_es )
>          {
> -            gprintk(XENLOG_ERR, "Null selector provided for CS, SS or TR\n");
> +            gprintk(XENLOG_ERR, "Empty segment attributes for CS, SS or TR\n");

... may I suggest "Null" or "Zero" instead of "Empty"?

Jan