Re: [Qemu-devel] [PATCH] virtio-pci: implement cfg capability

[Peter Maydell]

On 6 July 2015 at 11:03, Michael S. Tsirkin <address@hidden> wrote:
> On Mon, Jul 06, 2015 at 10:11:18AM +0100, Peter Maydell wrote:
>> But address_space_rw() is just the "memcpy bytes to the
>> target's memory" operation -- if you have a pile of bytes
>> then there are no endianness concerns. If you don't have
>> a pile of bytes then you need to know the structure of
>> the data you're DMAing around, and you should probably
>> have a loop doing things with the specify-the-width functions.

> Absolutely. But what if DMA happens to target another device
> and not memory? Device needs some endian-ness so it needs
> to be converted to that.

Yes, and address_space_rw() already deals with conversion to
that device's specified endianness.

-- PMM