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Re: [Qemu-ppc] Bug in qemu-system-ppc in Windows using the SDL2 GUI
From: |
Thomas Huth |
Subject: |
Re: [Qemu-ppc] Bug in qemu-system-ppc in Windows using the SDL2 GUI |
Date: |
Fri, 24 Mar 2017 10:33:04 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 |
On 24.03.2017 09:56, Mark Cave-Ayland wrote:
> On 24/03/17 08:47, Howard Spoelstra wrote:
>
>> Hi,
>>
>> Running qemu-system-ppc.exe in windows with the SDL2 GUI results in a
>> hangup. I bisected to this commit:
>>
>> 8bb93c6f99a42c2e0943bc904b283cd622d302c5 is the first bad commit
>> commit 8bb93c6f99a42c2e0943bc904b283cd622d302c5
>> Author: Alex Bennée <address@hidden>
>> Date: Wed Mar 15 14:48:25 2017 +0000
>>
>> ui/console: ensure graphic updates don't race with TCG vCPUs
>>
>> Commit 8d04fb55..
>>
>> tcg: drop global lock during TCG code execution
>>
>> ..broke the assumption that updates to the GUI couldn't happen at the
>> same time as TCG vCPUs where running. As a result the TCG vCPU could
>> still be updating a directly mapped frame-buffer while the display
>> side was updating. This would cause artefacts to appear when the
>> update code assumed that memory block hadn't changed.
>>
>> The simplest solution is to ensure the two things can't happen at the
>> same time like the old BQL locking scheme. Here we use the solution
>> introduced for MTTCG and schedule the update as async_safe_work when
>> we know no vCPUs can be running.
>>
>> Reported-by: Mark Cave-Ayland <address@hidden>
>> Signed-off-by: Alex Bennée <address@hidden>
>> Message-id: address@hidden
>> Cc: BALATON Zoltan <address@hidden>
>> Cc: Gerd Hoffmann <address@hidden>
>> Cc: Paolo Bonzini <address@hidden>
>> Signed-off-by: Alex Bennée <address@hidden>
>>
>> [ kraxel: updated comment clarifying the display adapters are buggy
>> and this is a temporary workaround ]
>>
>> Signed-off-by: Gerd Hoffmann <address@hidden>
>
> Hi Howard,
>
> Alex posted another patch yesterday to resolve a similar issue:
> https://lists.nongnu.org/archive/html/qemu-devel/2017-03/msg04474.html.
>
> Does applying the above patch help at all?
Luigi Burdo reported a similar issue here:
https://bugs.launchpad.net/qemu/+bug/1675549
Luigi, could you please try Alex' patch to see whether it fixes your crash?
Thanks,
Thomas