* [Qemu-devel] [PATCH v3] SGABIOS: fix wrong video attrs for int 10h, ah==13h
@ 2017-03-10 15:54 Herbie Robinson
2017-03-10 19:10 ` Laurent Vivier
2017-04-23 9:03 ` Michael Tokarev
0 siblings, 2 replies; 4+ messages in thread
From: Herbie Robinson @ 2017-03-10 15:54 UTC (permalink / raw)
To: qemu-devel; +Cc: qemu-trivial, lvivier, Herbie Robinson
Fix Bug #1670509: wrong video attrs for int 10h, ah==13h
The subroutine set_cursor_position is trashing %bx.
Unfortunately, %bl contains the video attribute for write_string.
The fix saves %bx in the function prolog and restores it in
the epilog.
Signed-off-by: Herbie Robinson <Herbie.Robinson@stratus.com>
---
Removed incorrect code deletions from set_current_cursor.
Removed explanation of same from the commit message.
BTW, I didn't see any test cases for this code, but if they exist
and somebody points me at them, I should be able to generate a
very small qcow2 file that demonstrates the problem.
sgabios.S | 2 ++
1 file changed, 2 insertions(+)
diff --git a/sgabios.S b/sgabios.S
index 275d063..96c4e23 100644
--- a/sgabios.S
+++ b/sgabios.S
@@ -1728,6 +1728,7 @@ write_string_tail:
set_cursor_position:
pushw %ax
+ pushw %bx
pushw %ds
pushw $BDA_SEG
popw %ds /* ds = 0x40 */
@@ -1738,6 +1739,7 @@ set_cursor_position:
movw %ax, %bx /* bx = cursor save offset */
movw %dx, (%bx) /* save new cursor value */
popw %ds
+ popw %bx
popw %ax
ret
--
1.8.3.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [PATCH v3] SGABIOS: fix wrong video attrs for int 10h, ah==13h
2017-03-10 15:54 [Qemu-devel] [PATCH v3] SGABIOS: fix wrong video attrs for int 10h, ah==13h Herbie Robinson
@ 2017-03-10 19:10 ` Laurent Vivier
2017-04-23 9:03 ` Michael Tokarev
1 sibling, 0 replies; 4+ messages in thread
From: Laurent Vivier @ 2017-03-10 19:10 UTC (permalink / raw)
To: Herbie Robinson, qemu-devel; +Cc: qemu-trivial
On 10/03/2017 16:54, Herbie Robinson wrote:
> Fix Bug #1670509: wrong video attrs for int 10h, ah==13h
> The subroutine set_cursor_position is trashing %bx.
> Unfortunately, %bl contains the video attribute for write_string.
>
> The fix saves %bx in the function prolog and restores it in
> the epilog.
>
> Signed-off-by: Herbie Robinson <Herbie.Robinson@stratus.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
> ---
> Removed incorrect code deletions from set_current_cursor.
> Removed explanation of same from the commit message.
>
> BTW, I didn't see any test cases for this code, but if they exist
> and somebody points me at them, I should be able to generate a
> very small qcow2 file that demonstrates the problem.
>
> sgabios.S | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/sgabios.S b/sgabios.S
> index 275d063..96c4e23 100644
> --- a/sgabios.S
> +++ b/sgabios.S
> @@ -1728,6 +1728,7 @@ write_string_tail:
>
> set_cursor_position:
> pushw %ax
> + pushw %bx
> pushw %ds
> pushw $BDA_SEG
> popw %ds /* ds = 0x40 */
> @@ -1738,6 +1739,7 @@ set_cursor_position:
> movw %ax, %bx /* bx = cursor save offset */
> movw %dx, (%bx) /* save new cursor value */
> popw %ds
> + popw %bx
> popw %ax
> ret
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [PATCH v3] SGABIOS: fix wrong video attrs for int 10h, ah==13h
2017-03-10 15:54 [Qemu-devel] [PATCH v3] SGABIOS: fix wrong video attrs for int 10h, ah==13h Herbie Robinson
2017-03-10 19:10 ` Laurent Vivier
@ 2017-04-23 9:03 ` Michael Tokarev
2017-04-24 12:08 ` Laurent Vivier
1 sibling, 1 reply; 4+ messages in thread
From: Michael Tokarev @ 2017-04-23 9:03 UTC (permalink / raw)
To: Herbie Robinson, qemu-devel; +Cc: qemu-trivial, lvivier
10.03.2017 18:54, Herbie Robinson wrote:
> Fix Bug #1670509: wrong video attrs for int 10h, ah==13h
> The subroutine set_cursor_position is trashing %bx.
> Unfortunately, %bl contains the video attribute for write_string.
>
> The fix saves %bx in the function prolog and restores it in
> the epilog.
>
> Signed-off-by: Herbie Robinson <Herbie.Robinson@stratus.com>
> ---
> Removed incorrect code deletions from set_current_cursor.
> Removed explanation of same from the commit message.
>
> BTW, I didn't see any test cases for this code, but if they exist
> and somebody points me at them, I should be able to generate a
> very small qcow2 file that demonstrates the problem.
>
> sgabios.S | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/sgabios.S b/sgabios.S
Now I'm not quite sure what to do with this.
It is part of sgabios, which is not qemu code but a submodule.
Maybe it's better to apply it upstream?
Or should we apply it directly?
Thanks,
/mjt
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [PATCH v3] SGABIOS: fix wrong video attrs for int 10h, ah==13h
2017-04-23 9:03 ` Michael Tokarev
@ 2017-04-24 12:08 ` Laurent Vivier
0 siblings, 0 replies; 4+ messages in thread
From: Laurent Vivier @ 2017-04-24 12:08 UTC (permalink / raw)
To: Michael Tokarev, Herbie Robinson, qemu-devel; +Cc: Paolo Bonzini
On 23/04/2017 11:03, Michael Tokarev wrote:
> 10.03.2017 18:54, Herbie Robinson wrote:
>> Fix Bug #1670509: wrong video attrs for int 10h, ah==13h
>> The subroutine set_cursor_position is trashing %bx.
>> Unfortunately, %bl contains the video attribute for write_string.
>>
>> The fix saves %bx in the function prolog and restores it in
>> the epilog.
>>
>> Signed-off-by: Herbie Robinson <Herbie.Robinson@stratus.com>
>> ---
>> Removed incorrect code deletions from set_current_cursor.
>> Removed explanation of same from the commit message.
>>
>> BTW, I didn't see any test cases for this code, but if they exist
>> and somebody points me at them, I should be able to generate a
>> very small qcow2 file that demonstrates the problem.
>>
>> sgabios.S | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/sgabios.S b/sgabios.S
>
> Now I'm not quite sure what to do with this.
>
> It is part of sgabios, which is not qemu code but a submodule.
>
> Maybe it's better to apply it upstream?
> Or should we apply it directly?
The original project is hosted by code.google.com, that has been closed
in 2015. I doesn't appear there is a real alive repository hosting this
project now (except some multiple clones on github).
So I think you should apply it directly (and regenerate sgabios.bin)
I cc Paolo as he has added the submodule.
Thanks,
Laurent
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2017-04-24 12:09 UTC | newest]
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2017-03-10 15:54 [Qemu-devel] [PATCH v3] SGABIOS: fix wrong video attrs for int 10h, ah==13h Herbie Robinson
2017-03-10 19:10 ` Laurent Vivier
2017-04-23 9:03 ` Michael Tokarev
2017-04-24 12:08 ` Laurent Vivier
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