From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752125AbbKKErV (ORCPT ); Tue, 10 Nov 2015 23:47:21 -0500 Received: from mail-oi0-f43.google.com ([209.85.218.43]:34001 "EHLO mail-oi0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751820AbbKKErS (ORCPT ); Tue, 10 Nov 2015 23:47:18 -0500 MIME-Version: 1.0 In-Reply-To: <1447202682.31884.123.camel@kernel.crashing.org> References: <20151109133624-mutt-send-email-mst@redhat.com> <1447109937.31884.42.camel@kernel.crashing.org> <1447121076.31884.61.camel@kernel.crashing.org> <1447133316.31884.67.camel@kernel.crashing.org> <1447151874.31884.82.camel@kernel.crashing.org> <1447194427.31884.100.camel@kernel.crashing.org> <1447202682.31884.123.camel@kernel.crashing.org> From: Andy Lutomirski Date: Tue, 10 Nov 2015 20:46:57 -0800 Message-ID: Subject: Re: [PATCH v4 0/6] virtio core DMA API conversion To: Benjamin Herrenschmidt Cc: Christian Borntraeger , David Woodhouse , Paolo Bonzini , Martin Schwidefsky , "Michael S. Tsirkin" , "David S. Miller" , Sebastian Ott , linux-s390 , Joerg Roedel , Cornelia Huck , KVM , Christoph Hellwig , "linux-kernel@vger.kernel.org" , Linux Virtualization , sparclinux@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Nov 10, 2015 4:44 PM, "Benjamin Herrenschmidt" wrote: > > On Tue, 2015-11-10 at 15:44 -0800, Andy Lutomirski wrote: > > > > > What about partition <-> partition virtio such as what we could do on > > > PAPR systems. That would have the weak barrier bit. > > > > > > > Is it partition <-> partition, bypassing IOMMU? > > No. > > > I think I'd settle for just something that doesn't regress > > non-experimental setups that actually work today and that allow new > > setups (x86 with fixed QEMU and maybe something more complicated on > > powerpc and/or sparc) to work in all cases. > > > > We could certainly just make powerpc and sparc continue bypassing the > > IOMMU until someone comes up with a way to fix it. I'll send out some > > patches that do that, and maybe that'll help this make progress. > > But we haven't found a solution that works. All we have come up with is > a quirk that will force bypass on virtio always and will not allow us > to operate non-bypassing devices on either of those architectures in > the future. > > I'm not too happy about this. Me neither. At least it wouldn't be a regression, but it's still crappy. I think that arm is fine, at least. I was unable to find an arm QEMU config that has any problems with my patches. --Andy From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Lutomirski Subject: Re: [PATCH v4 0/6] virtio core DMA API conversion Date: Tue, 10 Nov 2015 20:46:57 -0800 Message-ID: References: <20151109133624-mutt-send-email-mst@redhat.com> <1447109937.31884.42.camel@kernel.crashing.org> <1447121076.31884.61.camel@kernel.crashing.org> <1447133316.31884.67.camel@kernel.crashing.org> <1447151874.31884.82.camel@kernel.crashing.org> <1447194427.31884.100.camel@kernel.crashing.org> <1447202682.31884.123.camel@kernel.crashing.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1447202682.31884.123.camel@kernel.crashing.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org List-Archive: List-Post: To: Benjamin Herrenschmidt Cc: linux-s390 , sparclinux@vger.kernel.org, Joerg Roedel , KVM , "Michael S. Tsirkin" , "linux-kernel@vger.kernel.org" , Sebastian Ott , Christoph Hellwig , Christian Borntraeger , Martin Schwidefsky , Paolo Bonzini , Linux Virtualization , David Woodhouse , "David S. Miller" List-ID: On Nov 10, 2015 4:44 PM, "Benjamin Herrenschmidt" wrote: > > On Tue, 2015-11-10 at 15:44 -0800, Andy Lutomirski wrote: > > > > > What about partition <-> partition virtio such as what we could do on > > > PAPR systems. That would have the weak barrier bit. > > > > > > > Is it partition <-> partition, bypassing IOMMU? > > No. > > > I think I'd settle for just something that doesn't regress > > non-experimental setups that actually work today and that allow new > > setups (x86 with fixed QEMU and maybe something more complicated on > > powerpc and/or sparc) to work in all cases. > > > > We could certainly just make powerpc and sparc continue bypassing the > > IOMMU until someone comes up with a way to fix it. I'll send out some > > patches that do that, and maybe that'll help this make progress. > > But we haven't found a solution that works. All we have come up with is > a quirk that will force bypass on virtio always and will not allow us > to operate non-bypassing devices on either of those architectures in > the future. > > I'm not too happy about this. Me neither. At least it wouldn't be a regression, but it's still crappy. I think that arm is fine, at least. I was unable to find an arm QEMU config that has any problems with my patches. --Andy From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Lutomirski Date: Wed, 11 Nov 2015 04:46:57 +0000 Subject: Re: [PATCH v4 0/6] virtio core DMA API conversion Message-Id: List-Id: References: <20151109133624-mutt-send-email-mst@redhat.com> <1447109937.31884.42.camel@kernel.crashing.org> <1447121076.31884.61.camel@kernel.crashing.org> <1447133316.31884.67.camel@kernel.crashing.org> <1447151874.31884.82.camel@kernel.crashing.org> <1447194427.31884.100.camel@kernel.crashing.org> <1447202682.31884.123.camel@kernel.crashing.org> In-Reply-To: <1447202682.31884.123.camel@kernel.crashing.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Benjamin Herrenschmidt Cc: linux-s390 , sparclinux@vger.kernel.org, Joerg Roedel , KVM , "Michael S. Tsirkin" , "linux-kernel@vger.kernel.org" , Sebastian Ott , Christoph Hellwig , Christian Borntraeger , Martin Schwidefsky , Paolo Bonzini , Linux Virtualization , David Woodhouse , "David S. Miller" On Nov 10, 2015 4:44 PM, "Benjamin Herrenschmidt" wrote: > > On Tue, 2015-11-10 at 15:44 -0800, Andy Lutomirski wrote: > > > > > What about partition <-> partition virtio such as what we could do on > > > PAPR systems. That would have the weak barrier bit. > > > > > > > Is it partition <-> partition, bypassing IOMMU? > > No. > > > I think I'd settle for just something that doesn't regress > > non-experimental setups that actually work today and that allow new > > setups (x86 with fixed QEMU and maybe something more complicated on > > powerpc and/or sparc) to work in all cases. > > > > We could certainly just make powerpc and sparc continue bypassing the > > IOMMU until someone comes up with a way to fix it. I'll send out some > > patches that do that, and maybe that'll help this make progress. > > But we haven't found a solution that works. All we have come up with is > a quirk that will force bypass on virtio always and will not allow us > to operate non-bypassing devices on either of those architectures in > the future. > > I'm not too happy about this. Me neither. At least it wouldn't be a regression, but it's still crappy. I think that arm is fine, at least. I was unable to find an arm QEMU config that has any problems with my patches. --Andy