Re: [Qemu-devel] [PATCH v5 0/8] virtio endian-ambivalent target fixes

[Stefan Hajnoczi]

On Fri, Feb 21, 2014 at 12:28:03PM +0100, Greg Kurz wrote:
> This serie introduces helpers to enable virtio devices in a cross-endian
> environment. As of today, we only have legacy virtio but hopefully this
> helpers will be reused when we implement virtio 1.0.
> 
> Some assumptions are made for the legacy implementation:
> - all guest cpus have the same endianness
> - all virtio devices have the same endianness
> - endianness does not change while the device is in use
> 
> The decision to byteswap or not is hence controlled by a global variable that
> gets initialized on the virtio reset path for each device. This is slightly
> suboptimal, but since reset is not a critical path, it is a viable solution.
> 
> Of course, this patchset needs some arch specific enablement to be fully
> functionnal (PPC patches have already been posted to support KVM and TCG).
> 
> The changes since the last post are:
> - fixed SoB lines and subjects, as suggested by Andreas
> - fixed missing virtio_ in patch 2/8, spotted by Cornelia
> - relicensed virtio-access.h to GPLv2+ in patch 1/8, as requested by Rusty

The device conversions look fine but I think we should avoid using a
global bool.  I replied in more detail to Patch 1.