This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


RE: [Xen-devel] address mapping between domains

To: "Rik van Riel" <riel@xxxxxxxxxx>, "Mark Williamson" <Mark.Williamson@xxxxxxxxxxxx>
Subject: RE: [Xen-devel] address mapping between domains
From: "Ian Pratt" <m+Ian.Pratt@xxxxxxxxxxxx>
Date: Tue, 8 Mar 2005 23:22:08 -0000
Cc: <xen-devel@xxxxxxxxxxxxxxxxxxxxx>, <hzy@xxxxxxxxxxxxxx>, <ian.pratt@xxxxxxxxxxxx>
Delivery-date: Tue, 08 Mar 2005 23:23:16 +0000
Envelope-to: xen+James.Bulpin@xxxxxxxxxxxx
List-archive: <http://sourceforge.net/mailarchive/forum.php?forum=xen-devel>
List-help: <mailto:xen-devel-request@lists.sourceforge.net?subject=help>
List-id: List for Xen developers <xen-devel.lists.sourceforge.net>
List-post: <mailto:xen-devel@lists.sourceforge.net>
List-subscribe: <https://lists.sourceforge.net/lists/listinfo/xen-devel>, <mailto:xen-devel-request@lists.sourceforge.net?subject=subscribe>
List-unsubscribe: <https://lists.sourceforge.net/lists/listinfo/xen-devel>, <mailto:xen-devel-request@lists.sourceforge.net?subject=unsubscribe>
Sender: xen-devel-admin@xxxxxxxxxxxxxxxxxxxxx
Thread-index: AcUkNGRagrYV0tZGSd+3z3c/E1mHawAANKIw
Thread-topic: [Xen-devel] address mapping between domains
> > The domain that's controlling the real device (usually 
> dom0) maps the domU's 
> > memory before putting data into it (either directly or using PIO).
> Surely this could be optimised by (on a 64 bit system) mapping
> all of physical memory into dom0 kernel virtual memory, so it
> doesn't need to bother mapping and unmapping pages that IO is
> being done to ?

At the expense of protection, yes.

With sane DMA-capable hardware the driver domain never needs to actually
map the page into its address space anyhow. However, the grant table
stuff will still be required to enable us to configure the IO MMU
appropriately to allow the DMA (we expect to see such h/w support become


SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now.
Xen-devel mailing list