From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50367) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aaIFu-0004M9-2m for qemu-devel@nongnu.org; Mon, 29 Feb 2016 02:28:35 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aaIFq-0003mz-1H for qemu-devel@nongnu.org; Mon, 29 Feb 2016 02:28:34 -0500 Received: from mail-pa0-x22a.google.com ([2607:f8b0:400e:c03::22a]:34674) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aaIFp-0003mk-Pp for qemu-devel@nongnu.org; Mon, 29 Feb 2016 02:28:29 -0500 Received: by mail-pa0-x22a.google.com with SMTP id fy10so87353962pac.1 for ; Sun, 28 Feb 2016 23:28:29 -0800 (PST) References: <1456729587-17229-1-git-send-email-david@gibson.dropbear.id.au> <1456729587-17229-6-git-send-email-david@gibson.dropbear.id.au> From: Alexey Kardashevskiy Message-ID: <56D3F317.8050109@ozlabs.ru> Date: Mon, 29 Feb 2016 18:28:23 +1100 MIME-Version: 1.0 In-Reply-To: <1456729587-17229-6-git-send-email-david@gibson.dropbear.id.au> Content-Type: text/plain; charset=koi8-r; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCHv2 5/7] spapr_pci: (Mostly) remove spapr-pci-vfio-host-bridge List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: David Gibson , alex.williamson@redhat.com Cc: qemu-ppc@nongnu.org, agraf@suse.de, gwshan@au1.ibm.com, qemu-devel@nongnu.org On 02/29/2016 06:06 PM, David Gibson wrote: > Now that the regular spapr-pci-host-bridge can handle EEH, there are only > two things that spapr-pci-vfio-host-bridge does differently: > 1. automatically sizes its DMA window to match the host IOMMU > 2. checks if the attached VFIO container is backed by the > VFIO_SPAPR_TCE_IOMMU type on the host > > (1) is not particularly useful, since the default window used by the > regular host bridge will work with the host IOMMU configuration on all > current systems anyway. > > Plus, automatically changing guest visible configuration (such as the DMA > window) based on host settings is generally a bad idea. It's not > definitively broken, since spapr-pci-vfio-host-bridge is only supposed to > support VFIO devices which can't be migrated anyway, but still. > > (2) is not really useful, because if a guest tries to configure EEH on a > different host IOMMU, the first call will fail and that will be that. > > It's possible there are scripts or tools out there which expect > spapr-pci-vfio-host-bridge, so we don't remove it entirely. This patch > reduces it to just a stub for backwards compatibility. > > Signed-off-by: David Gibson Reviewed-by: Alexey Kardashevskiy -- Alexey