From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt Subject: Re: [PATCH v4 0/6] virtio core DMA API conversion Date: Wed, 11 Nov 2015 11:44:42 +1100 Message-ID: <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> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: 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: Andy Lutomirski Cc: linux-s390 , sparclinux@vger.kernel.org, KVM , "Michael S. Tsirkin" , Sebastian Ott , "linux-kernel@vger.kernel.org" , Christoph Hellwig , Christian Borntraeger , Joerg Roedel , Martin Schwidefsky , Paolo Bonzini , Linux Virtualization , David Woodhouse , "David S. Miller" List-ID: T24gVHVlLCAyMDE1LTExLTEwIGF0IDE1OjQ0IC0wODAwLCBBbmR5IEx1dG9taXJza2kgd3JvdGU6 Cj4gCj4gPiBXaGF0IGFib3V0IHBhcnRpdGlvbiA8LT4gcGFydGl0aW9uIHZpcnRpbyBzdWNoIGFz IHdoYXQgd2UgY291bGQgZG8gb24KPiA+IFBBUFIgc3lzdGVtcy4gVGhhdCB3b3VsZCBoYXZlIHRo ZSB3ZWFrIGJhcnJpZXIgYml0Lgo+ID4KPiAKPiBJcyBpdCBwYXJ0aXRpb24gPC0+IHBhcnRpdGlv biwgYnlwYXNzaW5nIElPTU1VPwoKTm8uCgo+IEkgdGhpbmsgSSdkIHNldHRsZSBmb3IganVzdCBz b21ldGhpbmcgdGhhdCBkb2Vzbid0IHJlZ3Jlc3MKPiBub24tZXhwZXJpbWVudGFsIHNldHVwcyB0 aGF0IGFjdHVhbGx5IHdvcmsgdG9kYXkgYW5kIHRoYXQgYWxsb3cgbmV3Cj4gc2V0dXBzICh4ODYg d2l0aCBmaXhlZCBRRU1VIGFuZCBtYXliZSBzb21ldGhpbmcgbW9yZSBjb21wbGljYXRlZCBvbgo+ IHBvd2VycGMgYW5kL29yIHNwYXJjKSB0byB3b3JrIGluIGFsbCBjYXNlcy4KPiAKPiBXZSBjb3Vs ZCBjZXJ0YWlubHkganVzdCBtYWtlIHBvd2VycGMgYW5kIHNwYXJjIGNvbnRpbnVlIGJ5cGFzc2lu ZyB0aGUKPiBJT01NVSB1bnRpbCBzb21lb25lIGNvbWVzIHVwIHdpdGggYSB3YXkgdG8gZml4IGl0 LsKgIEknbGwgc2VuZCBvdXQgc29tZQo+IHBhdGNoZXMgdGhhdCBkbyB0aGF0LCBhbmQgbWF5YmUg dGhhdCdsbCBoZWxwIHRoaXMgbWFrZSBwcm9ncmVzcy4KCkJ1dCB3ZSBoYXZlbid0IGZvdW5kIGEg c29sdXRpb24gdGhhdCB3b3Jrcy4gQWxsIHdlIGhhdmUgY29tZSB1cCB3aXRoIGlzCmEgcXVpcmsg dGhhdCB3aWxsIGZvcmNlIGJ5cGFzcyBvbiB2aXJ0aW8gYWx3YXlzIGFuZCB3aWxsIG5vdCBhbGxv dyB1cwp0byBvcGVyYXRlIG5vbi1ieXBhc3NpbmcgZGV2aWNlcyBvbiBlaXRoZXIgb2YgdGhvc2Ug YXJjaGl0ZWN0dXJlcyBpbgp0aGUgZnV0dXJlLgoKSSdtIG5vdCB0b28gaGFwcHkgYWJvdXQgdGhp cy4KCkJlbi4KCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f ClZpcnR1YWxpemF0aW9uIG1haWxpbmcgbGlzdApWaXJ0dWFsaXphdGlvbkBsaXN0cy5saW51eC1m b3VuZGF0aW9uLm9yZwpodHRwczovL2xpc3RzLmxpbnV4Zm91bmRhdGlvbi5vcmcvbWFpbG1hbi9s aXN0aW5mby92aXJ0dWFsaXphdGlvbg== From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt Date: Wed, 11 Nov 2015 00:44:42 +0000 Subject: Re: [PATCH v4 0/6] virtio core DMA API conversion Message-Id: <1447202682.31884.123.camel@kernel.crashing.org> 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> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: Andy Lutomirski Cc: linux-s390 , sparclinux@vger.kernel.org, KVM , "Michael S. Tsirkin" , Sebastian Ott , "linux-kernel@vger.kernel.org" , Christoph Hellwig , Christian Borntraeger , Joerg Roedel , Martin Schwidefsky , Paolo Bonzini , Linux Virtualization , David Woodhouse , "David S. Miller" On Tue, 2015-11-10 at 15:44 -0800, Andy Lutomirski wrote: >=20 > > What about partition <-> partition virtio such as what we could do on > > PAPR systems. That would have the weak barrier bit. > > >=20 > 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. >=20 > We could certainly just make powerpc and sparc continue bypassing the > IOMMU until someone comes up with a way to fix it.=C2=A0 I'll send out so= me > 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. Ben. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752573AbbKKApr (ORCPT ); Tue, 10 Nov 2015 19:45:47 -0500 Received: from gate.crashing.org ([63.228.1.57]:59113 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751864AbbKKApp (ORCPT ); Tue, 10 Nov 2015 19:45:45 -0500 Message-ID: <1447202682.31884.123.camel@kernel.crashing.org> Subject: Re: [PATCH v4 0/6] virtio core DMA API conversion From: Benjamin Herrenschmidt To: Andy Lutomirski Cc: Christian Borntraeger , Paolo Bonzini , David Woodhouse , Martin Schwidefsky , "Michael S. Tsirkin" , Sebastian Ott , "David S. Miller" , linux-s390 , Cornelia Huck , Joerg Roedel , KVM , Christoph Hellwig , Linux Virtualization , "linux-kernel@vger.kernel.org" , sparclinux@vger.kernel.org Date: Wed, 11 Nov 2015 11:44:42 +1100 In-Reply-To: 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> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.18.1 (3.18.1-1.fc23) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Ben.