Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752102AbbKVNGP (ORCPT ); Sun, 22 Nov 2015 08:06:15 -0500 Received: from mail-wm0-f53.google.com ([74.125.82.53]:35852 "EHLO mail-wm0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751606AbbKVNGN (ORCPT ); Sun, 22 Nov 2015 08:06:13 -0500 Reply-To: marcel@redhat.com Subject: Re: [PATCH v3 0/3] virtio DMA API core stuff References: <1446039327.3405.216.camel@infradead.org> <20151028155105-mutt-send-email-mst@redhat.com> <1446041609.3405.228.camel@infradead.org> <20151028161424-mutt-send-email-mst@redhat.com> <1446042754.3405.237.camel@infradead.org> <20151028175136-mutt-send-email-mst@redhat.com> <20151029104301-mutt-send-email-mst@redhat.com> <1446135536.3405.279.camel@infradead.org> <20151108120627-mutt-send-email-mst@redhat.com> <20151108114946.GG2255@suse.de> To: Joerg Roedel , "Michael S. Tsirkin" Cc: linux-s390 , KVM , Benjamin Herrenschmidt , Sebastian Ott , "linux-kernel@vger.kernel.org" , Andy Lutomirski , Christian Borntraeger , Andy Lutomirski , Paolo Bonzini , Linux Virtualization , David Woodhouse , Christoph Hellwig , Martin Schwidefsky From: Marcel Apfelbaum Message-ID: <5651BDC0.2040206@gmail.com> Date: Sun, 22 Nov 2015 15:06:08 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 MIME-Version: 1.0 In-Reply-To: <20151108114946.GG2255@suse.de> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1548 Lines: 43 On 11/08/2015 01:49 PM, Joerg Roedel wrote: > On Sun, Nov 08, 2015 at 12:37:47PM +0200, Michael S. Tsirkin wrote: >> I have no problem with that. For example, can we teach >> the DMA API on intel x86 to use PT for virtio by default? >> That would allow merging Andy's patches with >> full compatibility with old guests and hosts. > > Well, the only incompatibility comes from an experimental qemu feature, > more explicitly from a bug in that features implementation. So why > should we work around that in the kernel? I think it is not too hard to > fix qemu to generate a correct DMAR table which excludes the virtio > devices from iommu translation. Hi, I tried to generate a DMAR table that excludes some devices from IOMMU translation, however it does not help. The reason is, as far as I understand, that Linux kernel does not allow any device being outside an IOMMU scope if the iommu kernel option is activated. Does anybody know if it is "by design" or is simply an uncommon configuration? (some devices in an IOMMU scope, while others outside *any* IOMMU scope) Thanks, Marcel > > > Joerg > > _______________________________________________ > Virtualization mailing list > Virtualization@lists.linux-foundation.org > https://lists.linuxfoundation.org/mailman/listinfo/virtualization > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/