Re: [Qemu-devel] Re: Another SIGFPE in display code, now in cirrus

[Michael Tokarev <mjt@tls.msk.ru>]

12.05.2010 22:11, Stefano Stabellini wrote:
> On Wed, 12 May 2010, Jamie Lokier wrote:
>> Stefano Stabellini wrote:
>>> On Wed, 12 May 2010, Avi Kivity wrote:
>>>> It's useful if you have a one-line horizontal pattern you want to
>>>> propagate all over.
>>>
>>> It might be useful all right, but it is not entirely clear what the
>>> hardware should do in this situation from the documentation we have, and
>>> certainly the current state of the cirrus emulation code doesn't help.
>>
>> It's quite a reasonable thing for hardware to do, even if not documented.
>> It would be surprising if the hardware didn't copy the one-line pattern.
>
> All right then, you convinced me :)
>
> This is my proposed solution, however it is untested with Windows NT.

Well.  At least it does not crash anymore.

With this patch applied, when hitting "Test" (of a new video mode)
button on WindowsNT, the guest window gets resized to correct size,
but is painted with yellow and nothing happens.  The CPU enters
100%, and on the kvm console the following messages are displayed:

  BUG: kvm_dirty_pages_log_enable_slot: invalid parameters
  BUG: kvm_dirty_pages_log_enable_slot: invalid parameters

That's not new, it sometimes displays that shit on attempt to
migrate too, as I mentioned in another thread.

Thanks!

/mjt

> diff --git a/hw/cirrus_vga.c b/hw/cirrus_vga.c
> index 9f61a01..a7f0d3c 100644
> --- a/hw/cirrus_vga.c
> +++ b/hw/cirrus_vga.c
> @@ -676,15 +676,17 @@ static void cirrus_do_copy(CirrusVGAState *s, int dst, int src, int w, int h)
>       int sx, sy;
>       int dx, dy;
>       int width, height;
> +    uint32_t start_addr, line_offset, line_compare;
>       int depth;
>       int notify = 0;
[...]