From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan Beulich" Subject: Re: pre Sandy bridge IOMMU support (gm45) Date: Tue, 26 Jan 2016 03:52:20 -0700 Message-ID: <56A75DF402000078000CAFAF@prv-mh.provo.novell.com> References: <56A63F9502000078000CAAD1@prv-mh.provo.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Thierry Laurion Cc: xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org >>> On 25.01.16 at 22:49, wrote: > The case is 1) disabling iommu for IGD, unilaterally since i915 + gm45 > doesn't play well together. Iommu is still desired to isolate usb and > network devices, so we don't want to disable iommu completely. The side > effect of this would be to have IGD only for dom0, which would also > completely make sense in this use case. > > The point is the iommu=no-igfx doesn't fix the issue, since remapping seems > to still happen for IGD. Does that make sense ? It certainly may make sense, just that in what you have written so far I don't think I've been able to spot any evidence thereof. Since, as you say, nothing interesting gets logged by Xen, you must be drawing this conclusion from something (or else you wouldn't say "doesn't fix the issue"). Jan