RE: [Xen-users] PIO from domU

Vadim Makhervaks
Wed, 23 Nov 2005 22:01:35 -0000

Thanks, hack worked for me, for now; of course it would be really nice
to have a real and protected interface for such operation.

What do you envision to be a proper solution for this problem? Something
along the lines of module running in domO capable grant access or
transfer IO pages ownership to domU? Similar to existing grant_table
interface?

Vadim


-----Original Message-----
From: Ian Pratt [mailto:m+Ian.Pratt@cl.cam.ac.uk]
Sent: Tuesday, November 22, 2005 3:09 PM
To: Vadim Makhervaks; xen-users@lists.xensource.com
Cc: ian.pratt@cl.cam.ac.uk
Subject: RE: [Xen-users] PIO from domU

> We''re looking on sharing iWARP adapter by multiple guest
> domains, and having a direct adapter access.
>
> Does Xen/dom0 have a mechanism to map a page from adapter PCI
> address space to the domU memory space, and make it
> accessible by kernel/user space consumers running in domU?

Although Xen2 had this feature, the control API for it is currently
missing from xen3, but will be added back later. To enable you to make
progress with developing the rest of the s/w stack its probably easiest
to hack xen''s get_page_from_l1e so that it allows any domain to map IO
memory (we''ll fix this up properly in due course, allowing guests to be
granted regions of machine memory space)