Re: [Qemu-devel] [PATCH v8 00/20] virtio endian-ambivalent target

[Stefan Hajnoczi]

On Fri, Jun 13, 2014 at 01:18:00PM +0200, Greg Kurz wrote:
> This version merges the changes requested during the v7 review, remarks from
> ppc64 dump support review (yes, we talked about virtio there) and the work on
> virtio subsections migration. Also two new patches have been added:
> - patch #1 is a preliminary fix for virtio-serial posted by Alexander Graf
> - patch #9 prepares the work on the virtio_is_big_endian() helper
> 
> The most significant changes are:
> - introduction of a new CPU method for virtio
> - endianness is taken from CPU that resets the device
> - fastpath virtio memory accessors for fixed endian targets
> - VMState based virtio subsections (compatibility friendly)

I'm surprised it's not enough for the virtio device to have an
endianness field (big/little).  It seems these patches make endianness
depend on the CPUState through which the device is being accessed.

Can you explain why it's necessary to check the CPUState?

Stefan

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