From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gordan Bobic Subject: Re: Multi-bridged PCIe devices (Was: Re: iommuu/vt-d issues with LSI MegaSAS (PERC5i)) Date: Wed, 11 Sep 2013 12:25:18 +0100 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1VJiY0-0001Tr-8R for xen-devel@lists.xenproject.org; Wed, 11 Sep 2013 11:25:24 +0000 Received: from mail.shatteredsilicon.net (localhost [127.0.0.1]) by external.sentinel2 (Postfix) with ESMTP id 3618B220294 for ; Wed, 11 Sep 2013 12:25:19 +0100 (BST) In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xenproject.org List-Id: xen-devel@lists.xenproject.org It looks like I'm definitely not the first person to hit this problem: http://www.gossamer-threads.com/lists/xen/users/168557?do=post_view_threaded#168557 No responses or workarounds suggested back then. :( Gordan On Wed, 11 Sep 2013 12:05:35 +0100, Gordan Bobic wrote: > I found this: > > http://lists.xen.org/archives/html/xen-devel/2010-06/msg00093.html > > while looking for a solution to a similar problem. I am > facing a similar issue with LSI (8408E, 3081E-R) and > Adaptec (31605) SAS cards. Was there ever a proper, more general > fix or workaround for this issue? > > These SAS cards experience these problems in dom0. When running > a vanilla kernel on bare metal, they work OK without intel_iommu > set. As soon as I set intel_iommu, the same thing happens (on > bare metal, not dom0). > > Clearly there is something badly broken with multiple layers > of bridges when it comes to IOMMU in my setup (Intel 5520 PCIe > root hub -> NF200 bridge -> Intel 80333 Bridge -> SAS controller) > > I tried iommu=dom0-passthrough and it doesn't appear to have > helped. > > I am not seeing similar problems with other PCIe devices that > are also, in theory doing DMA (e.g. GPUs), but LSI and Adapted > controllers appear to be affected for some reason. > > Is there anything else I could try/do to make this work? > > Gordan > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel