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Date: Thu, 4 Jul 2013 11:37:25 +0300
From: "Michael S. Tsirkin" <mst@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] Citrix PV Bus device
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To: Peter Maydell <peter.maydell@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>, Paul Durrant <Paul.Durrant@citrix.com>, "xen-devel@lists.xen.org" <xen-devel@lists.xen.org>, Andreas =?iso-8859-1?Q?F=E4rber?= <afaerber@suse.de>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>

On Tue, Jul 02, 2013 at 12:10:17PM +0100, Peter Maydell wrote:
> On 2 July 2013 11:57, Paul Durrant <Paul.Durrant@citrix.com> wrote:
> >> -----Original Message-----
> >> From: Paolo Bonzini [mailto:pbonzini@redhat.com]
> >> > So the reason to place the device here is TARGET_PAGE_SIZE...
> >> > We really need a way to access that value from common code,
> >> > somewhere down my TODO list. :/
> 
> We probably don't, because it generally doesn't mean what you
> think it does. It's the smallest possible page size the guest
> CPU supports, which may not be the same as the actual page
> size the guest OS is using.
> 
> >> Why does it need to be in pages rather than bytes?
> 
> > It doesn't necessarily need to be in pages; it's just a more
> > convenient quantity than bytes.
> 
> It isn't really more convienient, because the guest would have
> to tell QEMU what the page size was. (I'm told that virtio is
> planning to move to a simple "just use a byte count" approach.)
> 
> thanks
> -- PMM

Yes, sometime in a distant future ...