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Re: [Xen-devel] Is there a way to map pv guest pseudo physical address i

To: Wei Liu <liuw@xxxxxxxxx>
Subject: Re: [Xen-devel] Is there a way to map pv guest pseudo physical address into dom0?
From: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
Date: Mon, 27 Jun 2011 10:01:57 +0100
Cc: Anthony, Perard <anthony.perard@xxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Stefano Stabellini <Stefano.Stabellini@xxxxxxxxxxxxx>
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On Mon, 2011-06-27 at 09:47 +0100, Wei Liu wrote:
> Hi, all
> 
> I'm reading the code of QEMU's virtio infrastructure (hw/virtio.c) and
> Linux's virtio driver (virtio_blk.c, virtio_net.c).
> 
> Virtio drivers utilize scatter gather infrastructure in the Linux
> kernel. It stores the physical addresses in scatter list. In Xen's hvm
> case, QEMU can access guest address space with
> cpu_physical_memory_map.
> 
> However, in Xen's pv case, this "physical address" will be "pseudo
> physical address". In order to retrieve theirs content, backend must
> map them into its own address space. I'm wondering if there is such
> infrastructure to get this job done.

I think you want one of xc_map_* provided by libxc (see xenctrl.h). (But
avoid xc_map_foreign_batch which is deprecated).

Ian.



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