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Re: [Qemu-devel] [PATCH 4/4] pci: use pci_config_header in pci.c
From: |
Gerd Hoffmann |
Subject: |
Re: [Qemu-devel] [PATCH 4/4] pci: use pci_config_header in pci.c |
Date: |
Thu, 02 Oct 2008 09:56:03 +0200 |
User-agent: |
Thunderbird 2.0.0.16 (X11/20080723) |
Anthony Liguori wrote:
> Because the config structure is loaded after pci_register device and
> because the MMIO callbacks into the config space? If you look at
> pci_default_read_config(), it actually does conversion from le to host
> CPU because that's what MMIO callbacks expect.
Yep.
> If you simply removed
> this, it would work.
Ah, *now* I see what you mean.
Well. That assumes the guests always use the correct in{b,w,l}
instruction to access the config space values, i.e. never ever try to
use two inb reads for a 16bit value for example. Or a inw for the lower
16 bits of a 32bit value because they know the high bits are zero anyway.
I have my doubts that this is a sane expectation.
> Of course, you'll have to audit each caller of
> pci_register_device() and make sure their config's get changed too.
Sure, that would be a *big* task & patch.
cheers,
Gerd
[Qemu-devel] [PATCH 2/4] pci: add config space struct (from qemu-xen)., Gerd Hoffmann, 2008/10/01
[Qemu-devel] [PATCH 3/4] pci: add default pci subsystem id for all devices., Gerd Hoffmann, 2008/10/01
Re: [Qemu-devel] [PATCH 1/4] add byteordered types to qemu., Christoph Hellwig, 2008/10/02