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Date: Thu, 25 Mar 2010 18:40:52 +0200
From: "Michael S. Tsirkin" <mst@redhat.com>
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Subject: [Qemu-devel] Re: [PATCH v3 1/1] Shared memory uio_pci driver
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To: Avi Kivity <avi@redhat.com>
Cc: Cam Macdonell <cam@cs.ualberta.ca>, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, qemu-devel@nongnu.org

On Thu, Mar 25, 2010 at 06:32:15PM +0200, Avi Kivity wrote:
> On 03/25/2010 06:23 PM, Anthony Liguori wrote:
>>> There has been previous discussion of virtio, however while virtio is
>>> good for exporting guest memory, it's not ideal for importing memory
>>> into a guest.
>>
>> virtio is a DMA-based API which means that it doesn't assume cache  
>> coherent shared memory.  The PCI transport takes advantage of cache  
>> coherent shared memory but it's not strictly required.
>
> Aren't we violating this by not using dma_alloc_coherent() for the queues?

I don't see what changing this would buys us though, unless
a non-cache coherent architecture implements kvm.
TCG runs everything on a single processor so there are
no cache coherency issues.

> -- 
> error compiling committee.c: too many arguments to function