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Re: [Qemu-devel] KVM call minutes 2013-01-29 - Port I/O
From: |
Anthony Liguori |
Subject: |
Re: [Qemu-devel] KVM call minutes 2013-01-29 - Port I/O |
Date: |
Wed, 30 Jan 2013 10:33:35 -0600 |
User-agent: |
Notmuch/0.13.2+93~ged93d79 (http://notmuchmail.org) Emacs/23.3.1 (x86_64-pc-linux-gnu) |
Gerd Hoffmann <address@hidden> writes:
> Hi,
>
>> hw/qxl.c: portio_list_add(qxl_vga_port_list,
>> pci_address_space_io(dev), 0x3b0);
>> hw/vga.c: portio_list_add(vga_port_list, address_space_io, 0x3b0);
>
> That reminds me I should solve this in a more elegant way.
>
> qxl takes over the vga io ports. The reason it does this is because qxl
> switches into vga mode in case the vga ports are accessed while not in
> vga mode. After doing the check (and possibly switching mode) the vga
> handler is called to actually handle it.
The best way to handle this would be to remodel how we do VGA.
Make VGACommonState a proper QOM object and use it as the base class for
QXL, CirrusVGA, QEMUVGA (std-vga), and VMwareVGA.
The VGA accessors should be exposed as a memory region but the sub class
ought to be responsible for actually adding it to a subregion.
>
> That twist makes it a bit hard to convert vga ...
>
> Anyone knows how one would do that with the memory api instead? I think
> taking over the ports is easy as the memory regions have priorities so I
> can simply register a region with higher priority. I have no clue how to
> forward the access to the vga code though.
>
That should be possible with priorities, but I think it's wrong. There
aren't two VGA devices. QXL is-a VGA device and the best way to
override behavior of base VGA device is through polymorphism.
This isn't really a memory API issue, it's a modeling issue.
Regards,
Anthony Liguori
> Anyone has clues / suggestions?
>
> thanks,
> Gerd
- Re: [Qemu-devel] KVM call minutes 2013-01-29 - Port I/O, (continued)
- Re: [Qemu-devel] KVM call minutes 2013-01-29 - Port I/O, Anthony Liguori, 2013/01/30
- Re: [Qemu-devel] KVM call minutes 2013-01-29 - Port I/O, Andreas Färber, 2013/01/30
- Re: [Qemu-devel] KVM call minutes 2013-01-29 - Port I/O, Michael S. Tsirkin, 2013/01/30
- Re: [Qemu-devel] KVM call minutes 2013-01-29 - Port I/O, Andreas Färber, 2013/01/30
- Re: [Qemu-devel] KVM call minutes 2013-01-29 - Port I/O, Michael S. Tsirkin, 2013/01/30
Re: [Qemu-devel] KVM call minutes 2013-01-29 - Port I/O, Anthony Liguori, 2013/01/30
Re: [Qemu-devel] KVM call minutes 2013-01-29 - Port I/O, Gerd Hoffmann, 2013/01/30
Re: [Qemu-devel] KVM call minutes 2013-01-29 - Port I/O, Andreas Färber, 2013/01/30
Re: [Qemu-devel] KVM call minutes 2013-01-29 - Port I/O, Benjamin Herrenschmidt, 2013/01/30
Re: [Qemu-devel] KVM call minutes 2013-01-29 - Port I/O, Anthony Liguori, 2013/01/30
Re: [Qemu-devel] KVM call minutes 2013-01-29 - Port I/O, Paolo Bonzini, 2013/01/30
Re: [Qemu-devel] KVM call minutes 2013-01-29 - Port I/O, Benjamin Herrenschmidt, 2013/01/30