From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: Re: [PATCH v2] Intel IOMMU patch to reprocess RMRR info Date: Fri, 28 Sep 2012 19:06:41 +0200 Message-ID: <20120928170641.GF18962@8bytes.org> References: <5065D1F5.1090003@hp.com> <20120928170106.GE18962@8bytes.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20120928170106.GE18962-zLv9SwRftAIdnm+yROfE0A@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Linda Knippers Cc: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, "Khan, Shuah" , David Woodhouse , "Mingarelli, Thomas" List-Id: iommu@lists.linux-foundation.org On Fri, Sep 28, 2012 at 07:01:06PM +0200, Joerg Roedel wrote: > On Fri, Sep 28, 2012 at 12:36:05PM -0400, Linda Knippers wrote: > > I can only speak to the HP servers. We have been shipping devices > > 'for a while' that provide sensor-type data to the platform. The > > device does DMA writes to a range of memory (the RMRR) and > > iLO does DMA reads of that data. > > And what PCI request-ids are used for these DMA transfers? Are this > request-ids which belong to devices Linux handles on its own? > > > If we address Alex's comments and we make a change to disallow the > > devices (non-USB devices?) with RMRRs from being assigned to > > a guest, will those changes be considered? > > This is overkill in my eyes. It means that *any* device which has an > RMRR defined, whether it is on your platform or not, can not be assigned > to a guest. > > I think it is better to have the RMRR regions mapped in the domains used > for DMA-API mappings and disallow to assign these devices to guests. Of course I meant "allow to assign these devices to guests." > For devices where this breaks we can implement some quirk-solution and > disallow guest assignment. But disallowing assignment of devices with > RMRR defined in general is pure overkill. > > > Joerg > > > _______________________________________________ > iommu mailing list > iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org > https://lists.linuxfoundation.org/mailman/listinfo/iommu