From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: Re: [PATCH linux-next] iommu: add iommu for s390 platform Date: Wed, 22 Oct 2014 16:17:29 +0200 Message-ID: <20141022141728.GG10074@8bytes.org> References: <1413892645-37657-1-git-send-email-blaschka@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1413892645-37657-1-git-send-email-blaschka-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@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: Frank Blaschka Cc: linux-s390-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, sebott-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, schwidefsky-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org, gerald.schaefer-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org List-Id: iommu@lists.linux-foundation.org Hi Frank, On Tue, Oct 21, 2014 at 01:57:25PM +0200, Frank Blaschka wrote: > Add a basic iommu for the s390 platform. The code is pretty simple > since on s390 each PCI device has its own virtual io address space > starting at the same vio address. Are there any limitations on IOVA address space for the devices or can be really any system physical address mapped starting from 0 to 2^64? > For this a domain could hold only one pci device. This bothers me, as it is not compatible with the IOMMU-API. I looked a little bit into how the mappings are created, and it seems there is a per-device dma_table. Is there any reason a dma_table can't be per IOMMU domain and assigned to multiple devices at the same time? Otherwise the code looks quite simple and straight forward. Joerg