From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Campbell Subject: Re: [TESTDAY] PV / HVM pass-through works when IOMMU present; weird failures when not Date: Fri, 28 Jun 2013 17:13:39 +0100 Message-ID: <1372436019.8976.171.camel@zakaz.uk.xensource.com> References: <51CDCF5302000078000E1A47@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <51CDCF5302000078000E1A47@nat28.tlf.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich Cc: George Dunlap , "xen-devel@lists.xen.org" List-Id: xen-devel@lists.xenproject.org On Fri, 2013-06-28 at 17:00 +0100, Jan Beulich wrote: > Also, I can't really see how the guest would be able to interact > with a half way assigned device properly - I could imagine you > being able to look at its config space, and perhaps load the > driver, but I can't see an I/O to succeed, at least not as long > as any bus mastering is being used the device (this ought to > crash this guest, another guest, or the host, or deliver corrupt > data). Purely port based I/O would likely work, but other than > serial cards I can't think of many things that would do so. That's what I was thinking. I would be useful to know what sort of device this is and to what extent it is "working". Ian.