Re: [Qemu-devel] [PATCH] virtio-gpu: fix crashes upon warm reboot with vga mode

[Peter Maydell]

On 7 August 2018 at 14:41, Gerd Hoffmann <address@hidden> wrote:
> On Tue, Aug 07, 2018 at 03:02:49PM +0200, Marc-André Lureau wrote:
>> Hi
>>
>> On Tue, Aug 7, 2018 at 2:55 PM, Gerd Hoffmann <address@hidden> wrote:
>> > On Fri, Aug 03, 2018 at 05:32:35PM +0200, Marc-André Lureau wrote:
>> >> With vga=775 on the Linux command line a first boot of the VM running
>> >> Linux works fine. After a warm reboot it crashes during Linux boot.
>> >>
>> >> Before that, valgrind points out bad memory write to console
>> >> surface. The VGA code is not aware that virtio-gpu got a message
>> >> surface scanout when the display is disabled. Let's reset VGA graphic
>> >> mode when it is the case, so that a new display surface is created
>> >> when doing further VGA operations.
>> >
>> > I guess we should simply call vga_common_reset() in virtio_vga_reset()
>> > instead, can you try that?
>> >
>> Yes I tried, and it still fails. However I think the call is missing
>> and I was planning to send it for 3.1 later, since I don't think it's
>> RC material.
>> The ordering of events is not completely obvious to me, but it's still
>> crashing/corrupting memory after the reset occurs. The scanout get's
>> disable after it iirc.
>
> Ok, lets go with this patch for -rc4 and figure the reset issues later.
> It is correct, even though I think there must be a simpler way to do it.
> When we have a better fix we can revert it.
>
> Peter, can you apply it directly?
>
> Reviewed-by: Gerd Hoffmann <address@hidden>

Applied to master, thanks.

-- PMM