From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54603) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WnoCr-0002Fh-8L for qemu-devel@nongnu.org; Fri, 23 May 2014 08:04:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WnoCk-0006vt-Um for qemu-devel@nongnu.org; Fri, 23 May 2014 08:04:13 -0400 Received: from mail-pa0-f51.google.com ([209.85.220.51]:63377) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WnoCk-0006vW-OB for qemu-devel@nongnu.org; Fri, 23 May 2014 08:04:06 -0400 Received: by mail-pa0-f51.google.com with SMTP id kq14so4063536pab.10 for ; Fri, 23 May 2014 05:04:05 -0700 (PDT) Message-ID: <537F392B.7020209@ozlabs.ru> Date: Fri, 23 May 2014 22:03:55 +1000 From: Alexey Kardashevskiy MIME-Version: 1.0 References: <1400821160-25258-1-git-send-email-aik@ozlabs.ru> <1400821160-25258-6-git-send-email-aik@ozlabs.ru> <537F30C7.3010704@suse.de> In-Reply-To: <537F30C7.3010704@suse.de> Content-Type: text/plain; charset=KOI8-R Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v6 5/7] vfio: Introduce VFIO address spaces List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexander Graf , qemu-devel@nongnu.org Cc: Alex Williamson , qemu-ppc@nongnu.org, David Gibson On 05/23/2014 09:28 PM, Alexander Graf wrote: > > On 23.05.14 06:59, Alexey Kardashevskiy wrote: >> From: David Gibson >> >> The only model so far supported for VFIO passthrough devices is the model >> usually used on x86, where all of the guest's RAM is mapped into the >> (host) IOMMU and there is no IOMMU visible in the guest. >> >> This patch begins to relax this model, introducing the notion of a >> VFIOAddressSpace. This represents a logical DMA address space which will >> be visible to one or more VFIO devices by appropriate mapping in the (host) >> IOMMU. Thus the currently global list of containers becomes local to >> a VFIOAddressSpace, and we verify that we don't attempt to add a VFIO >> group to multiple address spaces. >> >> For now, only one VFIOAddressSpace is created and used, corresponding to >> main system memory, that will change in future patches. >> >> Signed-off-by: David Gibson >> Signed-off-by: Alexey Kardashevskiy > > Don't we already have a DMA address space in the PCI bus? We could just use > that one instead, no? I do not know about x86, but for spapr that VFIOAddressSpace is nothing but wrapper around an AddressSpace from the SPAPR PHB. -- Alexey