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Re: [Qemu-devel] Cirrus bugs vs endian: how two bugs cancel each other o
From: |
Anthony Liguori |
Subject: |
Re: [Qemu-devel] Cirrus bugs vs endian: how two bugs cancel each other out |
Date: |
Mon, 30 Jul 2012 09:29:01 -0500 |
User-agent: |
Notmuch/0.13.2+93~ged93d79 (http://notmuchmail.org) Emacs/23.3.1 (x86_64-pc-linux-gnu) |
Avi Kivity <address@hidden> writes:
>>> Virtio makes sense for qxl, but for now we have the original pci model
>>> which I don't see a reason why it can't work for ppc.
>>
>> I'm sure it can work for PPC given enough effort. But I think the
>> question becomes, why not invest that effort in moving qxl to the
>> standard transport that the rest of our PV devices use.
>
> The drm drivers for the current model are needed anyway; so moving to
> virtio is extra effort, not an alternative.
This is just a point in time statement. If we were serious about using
virtio then we could quickly introduce a virtio transport and only
target the DRM drivers at the virtio transport.
> Note virtio doesn't support mapping framebuffers yet
Yes. I haven't seen a good proposal yet on how to handle this. I think
this is the main problem to solve.
> or the entire vga compatibility stuff
This is actually independent of virtio. A virtio-pci device could
expose it's class code as a VGA adapter and also handle I/O accesses for
the legacy region. This is strictly a PC-ism.
For non-virtio-pci versions of the device, the legacy I/O area would not exist.
> so the pc-oriented card will have to be a mix of
> virtio and stdvga multiplexed on one pci card (maybe two functions, but
> I'd rather avoid that).
Yes. We could modify stdvga to expose the VGA ram area as the second
bar and make the first bar a virtio-pci compatible area. This would
require modifying the VGA bios to understand the change but otherwise,
should be compatible.
It would take modeling VGACommonState as a proper device and then it's a
pretty simple process of embedding a VGACommonState within a virtio-pci
device. It should work fairly well.
It gets a little complicated in terms of who owns the DisplayState but
that's a solvable problem.
Regards,
Anthony Liguori
>
> --
> error compiling committee.c: too many arguments to function
- Re: [Qemu-devel] Cirrus bugs vs endian: how two bugs cancel each other out, (continued)
- Re: [Qemu-devel] Cirrus bugs vs endian: how two bugs cancel each other out, Alon Levy, 2012/07/30
- Re: [Qemu-devel] Cirrus bugs vs endian: how two bugs cancel each other out, Anthony Liguori, 2012/07/30
- Re: [Qemu-devel] Cirrus bugs vs endian: how two bugs cancel each other out, Benjamin Herrenschmidt, 2012/07/30
- Re: [Qemu-devel] Cirrus bugs vs endian: how two bugs cancel each other out, Alon Levy, 2012/07/31
- Re: [Qemu-devel] Cirrus bugs vs endian: how two bugs cancel each other out, Anthony Liguori, 2012/07/30
- Re: [Qemu-devel] Cirrus bugs vs endian: how two bugs cancel each other out, Avi Kivity, 2012/07/30
- Re: [Qemu-devel] Cirrus bugs vs endian: how two bugs cancel each other out, Anthony Liguori, 2012/07/30
- Re: [Qemu-devel] Cirrus bugs vs endian: how two bugs cancel each other out, Avi Kivity, 2012/07/30
- Re: [Qemu-devel] Cirrus bugs vs endian: how two bugs cancel each other out,
Anthony Liguori <=
- Re: [Qemu-devel] Cirrus bugs vs endian: how two bugs cancel each other out, Avi Kivity, 2012/07/30
- Re: [Qemu-devel] Cirrus bugs vs endian: how two bugs cancel each other out, Anthony Liguori, 2012/07/30
- Re: [Qemu-devel] Cirrus bugs vs endian: how two bugs cancel each other out, Rusty Russell, 2012/07/30
- Re: [Qemu-devel] Cirrus bugs vs endian: how two bugs cancel each other out, Benjamin Herrenschmidt, 2012/07/30
- Re: [Qemu-devel] Cirrus bugs vs endian: how two bugs cancel each other out, Alon Levy, 2012/07/31
- Re: [Qemu-devel] Cirrus bugs vs endian: how two bugs cancel each other out, Benjamin Herrenschmidt, 2012/07/30
- Re: [Qemu-devel] Cirrus bugs vs endian: how two bugs cancel each other out, Anthony Liguori, 2012/07/30
- Re: [Qemu-devel] Cirrus bugs vs endian: how two bugs cancel each other out, Benjamin Herrenschmidt, 2012/07/30
- Re: [Qemu-devel] Cirrus bugs vs endian: how two bugs cancel each other out, Alon Levy, 2012/07/30
Re: [Qemu-devel] Cirrus bugs vs endian: how two bugs cancel each other out, Blue Swirl, 2012/07/30