From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: swiotlb=force in Konrad's xen-pcifront-0.8.2 pvops domU kernel with PCI passthrough Date: Fri, 12 Nov 2010 11:58:40 -0500 Message-ID: <20101112165840.GB10339@dumpdata.com> References: <20101111160459.GB25654@dumpdata.com> <20101111190351.GB15530@dumpdata.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Dante Cinco Cc: Xen-devel List-Id: xen-devel@lists.xenproject.org On Thu, Nov 11, 2010 at 05:02:55PM -0800, Dante Cinco wrote: > Here's another datapoint: with iommu=1,passthrough,no-intremap,verbose > in the Xen command line and iommu=soft in the pvops domU command line > also results in an NMI (see below). Replacing iommu=soft with Ok, so that enabled the VT-D and enables you to do 64-bit DMA. > swiotlb=force in pvops domU works reliably but with the I/O > performance degradation. It seems that regardless of whether iommu is > enabled or disabled in the hypervisor, swiotlb=force is necessary in > the pvops domU. That is bizzare. I am pretty sure it should work just fine with 'iommu=soft'. My test scripts confirm this, but let me run once more just to make sure.