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Re: [Qemu-devel] [PATCH] virtio-pci: implement cfg capability
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH] virtio-pci: implement cfg capability |
Date: |
Mon, 6 Jul 2015 12:06:28 +0300 |
On Mon, Jul 06, 2015 at 10:46:31AM +0200, Paolo Bonzini wrote:
>
>
> On 06/07/2015 10:33, Michael S. Tsirkin wrote:
> > Also, by luck, some values work the same whatever the endian-ness.
> > E.g. dma_memory_set fills the buffer with a given pattern, so
> > nothing changes if you byte-swap it.
> >
> > Here's an example that's wrong: dp8393x. Typically it's accessing
> > memory for DMA, so there's no byteswap. Works fine.
> >
> > But should device attempt to access another device memory,
> > it would break because MIPS target is BE.
> >
> > Cc Hervé for confirmation.
> >
> > I conclude that virtio is not so special in needing a variant
> > of address_space_rw that assumes host endian format for the data.
>
> Why host endian and not device (in this case little) endian?
>
> Paolo
It's the endian of the originator of the transaction.
And emulated device code is all compiled in host endian-ness.
--
MST
- [Qemu-devel] [PATCH] virtio-pci: implement cfg capability, Michael S. Tsirkin, 2015/07/02
- Re: [Qemu-devel] [PATCH] virtio-pci: implement cfg capability, Paolo Bonzini, 2015/07/02
- Re: [Qemu-devel] [PATCH] virtio-pci: implement cfg capability, Michael S. Tsirkin, 2015/07/02
- Re: [Qemu-devel] [PATCH] virtio-pci: implement cfg capability, Paolo Bonzini, 2015/07/02
- Re: [Qemu-devel] [PATCH] virtio-pci: implement cfg capability, Michael S. Tsirkin, 2015/07/04
- Re: [Qemu-devel] [PATCH] virtio-pci: implement cfg capability, Paolo Bonzini, 2015/07/06
- Re: [Qemu-devel] [PATCH] virtio-pci: implement cfg capability, Michael S. Tsirkin, 2015/07/06
- Re: [Qemu-devel] [PATCH] virtio-pci: implement cfg capability, Paolo Bonzini, 2015/07/06
- Re: [Qemu-devel] [PATCH] virtio-pci: implement cfg capability,
Michael S. Tsirkin <=
- Re: [Qemu-devel] [PATCH] virtio-pci: implement cfg capability, Peter Maydell, 2015/07/06
- Re: [Qemu-devel] [PATCH] virtio-pci: implement cfg capability, Michael S. Tsirkin, 2015/07/06
- Re: [Qemu-devel] [PATCH] virtio-pci: implement cfg capability, Peter Maydell, 2015/07/06
- Re: [Qemu-devel] [PATCH] virtio-pci: implement cfg capability, Michael S. Tsirkin, 2015/07/06
- Re: [Qemu-devel] [PATCH] virtio-pci: implement cfg capability, Peter Maydell, 2015/07/06
- Re: [Qemu-devel] [PATCH] virtio-pci: implement cfg capability, Paolo Bonzini, 2015/07/06
- Re: [Qemu-devel] [PATCH] virtio-pci: implement cfg capability, Michael S. Tsirkin, 2015/07/06
- Re: [Qemu-devel] [PATCH] virtio-pci: implement cfg capability, Michael S. Tsirkin, 2015/07/06
- Re: [Qemu-devel] [PATCH] virtio-pci: implement cfg capability, Paolo Bonzini, 2015/07/06
Re: [Qemu-devel] [PATCH] virtio-pci: implement cfg capability, Gerd Hoffmann, 2015/07/03