From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161880AbbKTC5r (ORCPT ); Thu, 19 Nov 2015 21:57:47 -0500 Received: from gate.crashing.org ([63.228.1.57]:50017 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161124AbbKTC5p (ORCPT ); Thu, 19 Nov 2015 21:57:45 -0500 Message-ID: <1447988199.3016.2.camel@kernel.crashing.org> Subject: Re: [PATCH v3 0/3] virtio DMA API core stuff From: Benjamin Herrenschmidt To: David Woodhouse , Andy Lutomirski , "Michael S. Tsirkin" Cc: Christian Borntraeger , Paolo Bonzini , "linux-kernel@vger.kernel.org" , Martin Schwidefsky , Sebastian Ott , linux-s390 , Cornelia Huck , Joerg Roedel , Linux Virtualization , Christoph Hellwig , KVM Date: Fri, 20 Nov 2015 13:56:39 +1100 In-Reply-To: <1447976286.145626.122.camel@infradead.org> References: <20151119153821-mutt-send-email-mst@redhat.com> <1447976286.145626.122.camel@infradead.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 Thu, 2015-11-19 at 23:38 +0000, David Woodhouse wrote: > > I understand that POWER and other platforms don't currently have a > clean way to indicate that certain device don't have translation. And I > understand that we may end up with a *quirk* which ensures that the DMA > API does the right thing (i.e. nothing) in certain cases. > > But we should *NOT* be involving the virtio device drivers in that > quirk, in any way. And putting a feature bit in the virtio device > itself doesn't seem at all sane either. > > Bear in mind that qemu-system-x86_64 currently has the *same* problem > with assigned physical devices. It's claiming they're translated, and > they're not. It's not that clear but yeah ... as I mentioned, I can't find a way to do that quirk that won't break when we want to actually use the iommu...  Ben. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt Subject: Re: [PATCH v3 0/3] virtio DMA API core stuff Date: Fri, 20 Nov 2015 13:56:39 +1100 Message-ID: <1447988199.3016.2.camel@kernel.crashing.org> References: <20151119153821-mutt-send-email-mst@redhat.com> <1447976286.145626.122.camel@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <1447976286.145626.122.camel@infradead.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: David Woodhouse , Andy Lutomirski , "Michael S. Tsirkin" Cc: linux-s390 , KVM , Sebastian Ott , "linux-kernel@vger.kernel.org" , Linux Virtualization , Christian Borntraeger , Joerg Roedel , Martin Schwidefsky , Paolo Bonzini , Christoph Hellwig List-ID: T24gVGh1LCAyMDE1LTExLTE5IGF0IDIzOjM4ICswMDAwLCBEYXZpZCBXb29kaG91c2Ugd3JvdGU6 Cj4gCj4gSSB1bmRlcnN0YW5kIHRoYXQgUE9XRVIgYW5kIG90aGVyIHBsYXRmb3JtcyBkb24ndCBj dXJyZW50bHkgaGF2ZSBhCj4gY2xlYW4gd2F5IHRvIGluZGljYXRlIHRoYXQgY2VydGFpbiBkZXZp Y2UgZG9uJ3QgaGF2ZSB0cmFuc2xhdGlvbi4gQW5kIEkKPiB1bmRlcnN0YW5kIHRoYXQgd2UgbWF5 IGVuZCB1cCB3aXRoIGEgKnF1aXJrKiB3aGljaCBlbnN1cmVzIHRoYXQgdGhlIERNQQo+IEFQSSBk b2VzIHRoZSByaWdodCB0aGluZyAoaS5lLiBub3RoaW5nKSBpbiBjZXJ0YWluIGNhc2VzLgo+IAo+ IEJ1dCB3ZSBzaG91bGQgKk5PVCogYmUgaW52b2x2aW5nIHRoZSB2aXJ0aW8gZGV2aWNlIGRyaXZl cnMgaW4gdGhhdAo+IHF1aXJrLCBpbiBhbnkgd2F5LiBBbmQgcHV0dGluZyBhIGZlYXR1cmUgYml0 IGluIHRoZSB2aXJ0aW8gZGV2aWNlCj4gaXRzZWxmIGRvZXNuJ3Qgc2VlbSBhdCBhbGwgc2FuZSBl aXRoZXIuCj4gCj4gQmVhciBpbiBtaW5kIHRoYXQgcWVtdS1zeXN0ZW0teDg2XzY0IGN1cnJlbnRs eSBoYXMgdGhlICpzYW1lKiBwcm9ibGVtCj4gd2l0aCBhc3NpZ25lZCBwaHlzaWNhbCBkZXZpY2Vz LiBJdCdzIGNsYWltaW5nIHRoZXkncmUgdHJhbnNsYXRlZCwgYW5kCj4gdGhleSdyZSBub3QuCgpJ dCdzIG5vdCB0aGF0IGNsZWFyIGJ1dCB5ZWFoIC4uLiBhcyBJIG1lbnRpb25lZCwgSSBjYW4ndCBm aW5kIGEKd2F5IHRvIGRvIHRoYXQgcXVpcmsgdGhhdCB3b24ndCBicmVhayB3aGVuIHdlIHdhbnQg dG8gYWN0dWFsbHkgdXNlCnRoZSBpb21tdS4uLsKgCgpCZW4uCgpfX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fXwpWaXJ0dWFsaXphdGlvbiBtYWlsaW5nIGxpc3QK VmlydHVhbGl6YXRpb25AbGlzdHMubGludXgtZm91bmRhdGlvbi5vcmcKaHR0cHM6Ly9saXN0cy5s aW51eGZvdW5kYXRpb24ub3JnL21haWxtYW4vbGlzdGluZm8vdmlydHVhbGl6YXRpb24=