From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932293AbeDCNMo (ORCPT ); Tue, 3 Apr 2018 09:12:44 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:50306 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932260AbeDCNMl (ORCPT ); Tue, 3 Apr 2018 09:12:41 -0400 Date: Tue, 3 Apr 2018 16:12:39 +0300 From: "Michael S. Tsirkin" To: Alexander Duyck Cc: "Daly, Dan" , Bjorn Helgaas , "Duyck, Alexander H" , linux-pci@vger.kernel.org, virtio-dev@lists.oasis-open.org, kvm@vger.kernel.org, Netdev , LKML , linux-nvme@lists.infradead.org, Keith Busch , netanel@amazon.com, Don Dutile , Maximilian Heyne , "Wang, Liang-min" , "Rustad, Mark D" , David Woodhouse , Christoph Hellwig , dwmw@amazon.co.uk Subject: Re: [virtio-dev] [pci PATCH v7 2/5] virtio_pci: Add support for unmanaged SR-IOV on virtio_pci devices Message-ID: <20180403161151-mutt-send-email-mst@kernel.org> References: <20180315183449.3102.64791.stgit@localhost.localdomain> <20180315184132.3102.90947.stgit@localhost.localdomain> <20180316183042-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 16, 2018 at 09:40:34AM -0700, Alexander Duyck wrote: > On Fri, Mar 16, 2018 at 9:34 AM, Michael S. Tsirkin wrote: > > On Thu, Mar 15, 2018 at 11:42:41AM -0700, Alexander Duyck wrote: > >> From: Alexander Duyck > >> > >> Hardware-realized virtio_pci devices can implement SR-IOV, so this > >> patch enables its use. The device in question is an upcoming Intel > >> NIC that implements both a virtio_net PF and virtio_net VFs. These > >> are hardware realizations of what has been up to now been a software > >> interface. > >> > >> The device in question has the following 4-part PCI IDs: > >> > >> PF: vendor: 1af4 device: 1041 subvendor: 8086 subdevice: 15fe > >> VF: vendor: 1af4 device: 1041 subvendor: 8086 subdevice: 05fe > >> > >> The patch currently needs no check for device ID, because the callback > >> will never be made for devices that do not assert the capability or > >> when run on a platform incapable of SR-IOV. > >> > >> One reason for this patch is because the hardware requires the > >> vendor ID of a VF to be the same as the vendor ID of the PF that > >> created it. So it seemed logical to simply have a fully-functioning > >> virtio_net PF create the VFs. This patch makes that possible. > >> > >> Reviewed-by: Christoph Hellwig > >> Signed-off-by: Mark Rustad > >> Signed-off-by: Alexander Duyck > > > > So if and when virtio PFs can manage the VFs, then we can > > add a feature bit for that? > > Seems reasonable. > > Yes. If nothing else you may not even need a feature bit depending on > how things go. OTOH if the interface is changed in an incompatible way, and old Linux will attempt to drive the new device since there is no check. I think we should add a feature bit right away. > One of the reasons why Mark called out the > subvendor/subdevice was because that might be able to be used to > identify the specific hardware that is providing the SR-IOV feature so > in the future if it is added to virtio itself then you could exclude > devices like this by just limiting things based on subvendor/subdevice > IDs. > > > Also, I am guessing that hardware implementations will want > > to add things like stong memory barriers - I guess we > > will add new feature bits for that too down the road? > > That piece I don't have visibility into at this time. Perhaps Dan > might have more visibility into future plans on what this might need. > > Thanks. > > - Alex From mboxrd@z Thu Jan 1 00:00:00 1970 From: mst@redhat.com (Michael S. Tsirkin) Date: Tue, 3 Apr 2018 16:12:39 +0300 Subject: [virtio-dev] [pci PATCH v7 2/5] virtio_pci: Add support for unmanaged SR-IOV on virtio_pci devices In-Reply-To: References: <20180315183449.3102.64791.stgit@localhost.localdomain> <20180315184132.3102.90947.stgit@localhost.localdomain> <20180316183042-mutt-send-email-mst@kernel.org> Message-ID: <20180403161151-mutt-send-email-mst@kernel.org> On Fri, Mar 16, 2018@09:40:34AM -0700, Alexander Duyck wrote: > On Fri, Mar 16, 2018@9:34 AM, Michael S. Tsirkin wrote: > > On Thu, Mar 15, 2018@11:42:41AM -0700, Alexander Duyck wrote: > >> From: Alexander Duyck > >> > >> Hardware-realized virtio_pci devices can implement SR-IOV, so this > >> patch enables its use. The device in question is an upcoming Intel > >> NIC that implements both a virtio_net PF and virtio_net VFs. These > >> are hardware realizations of what has been up to now been a software > >> interface. > >> > >> The device in question has the following 4-part PCI IDs: > >> > >> PF: vendor: 1af4 device: 1041 subvendor: 8086 subdevice: 15fe > >> VF: vendor: 1af4 device: 1041 subvendor: 8086 subdevice: 05fe > >> > >> The patch currently needs no check for device ID, because the callback > >> will never be made for devices that do not assert the capability or > >> when run on a platform incapable of SR-IOV. > >> > >> One reason for this patch is because the hardware requires the > >> vendor ID of a VF to be the same as the vendor ID of the PF that > >> created it. So it seemed logical to simply have a fully-functioning > >> virtio_net PF create the VFs. This patch makes that possible. > >> > >> Reviewed-by: Christoph Hellwig > >> Signed-off-by: Mark Rustad > >> Signed-off-by: Alexander Duyck > > > > So if and when virtio PFs can manage the VFs, then we can > > add a feature bit for that? > > Seems reasonable. > > Yes. If nothing else you may not even need a feature bit depending on > how things go. OTOH if the interface is changed in an incompatible way, and old Linux will attempt to drive the new device since there is no check. I think we should add a feature bit right away. > One of the reasons why Mark called out the > subvendor/subdevice was because that might be able to be used to > identify the specific hardware that is providing the SR-IOV feature so > in the future if it is added to virtio itself then you could exclude > devices like this by just limiting things based on subvendor/subdevice > IDs. > > > Also, I am guessing that hardware implementations will want > > to add things like stong memory barriers - I guess we > > will add new feature bits for that too down the road? > > That piece I don't have visibility into at this time. Perhaps Dan > might have more visibility into future plans on what this might need. > > Thanks. > > - Alex From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-dev-return-3707-cohuck=redhat.com@lists.oasis-open.org Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [66.179.20.138]) by lists.oasis-open.org (Postfix) with ESMTP id 2EA755818F8A for ; Tue, 3 Apr 2018 06:12:52 -0700 (PDT) Date: Tue, 3 Apr 2018 16:12:39 +0300 From: "Michael S. Tsirkin" Message-ID: <20180403161151-mutt-send-email-mst@kernel.org> References: <20180315183449.3102.64791.stgit@localhost.localdomain> <20180315184132.3102.90947.stgit@localhost.localdomain> <20180316183042-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [virtio-dev] [pci PATCH v7 2/5] virtio_pci: Add support for unmanaged SR-IOV on virtio_pci devices To: Alexander Duyck Cc: "Daly, Dan" , Bjorn Helgaas , "Duyck, Alexander H" , linux-pci@vger.kernel.org, virtio-dev@lists.oasis-open.org, kvm@vger.kernel.org, Netdev , LKML , linux-nvme@lists.infradead.org, Keith Busch , netanel@amazon.com, Don Dutile , Maximilian Heyne , "Wang, Liang-min" , "Rustad, Mark D" , David Woodhouse , Christoph Hellwig , dwmw@amazon.co.uk List-ID: On Fri, Mar 16, 2018 at 09:40:34AM -0700, Alexander Duyck wrote: > On Fri, Mar 16, 2018 at 9:34 AM, Michael S. Tsirkin wrote: > > On Thu, Mar 15, 2018 at 11:42:41AM -0700, Alexander Duyck wrote: > >> From: Alexander Duyck > >> > >> Hardware-realized virtio_pci devices can implement SR-IOV, so this > >> patch enables its use. The device in question is an upcoming Intel > >> NIC that implements both a virtio_net PF and virtio_net VFs. These > >> are hardware realizations of what has been up to now been a software > >> interface. > >> > >> The device in question has the following 4-part PCI IDs: > >> > >> PF: vendor: 1af4 device: 1041 subvendor: 8086 subdevice: 15fe > >> VF: vendor: 1af4 device: 1041 subvendor: 8086 subdevice: 05fe > >> > >> The patch currently needs no check for device ID, because the callback > >> will never be made for devices that do not assert the capability or > >> when run on a platform incapable of SR-IOV. > >> > >> One reason for this patch is because the hardware requires the > >> vendor ID of a VF to be the same as the vendor ID of the PF that > >> created it. So it seemed logical to simply have a fully-functioning > >> virtio_net PF create the VFs. This patch makes that possible. > >> > >> Reviewed-by: Christoph Hellwig > >> Signed-off-by: Mark Rustad > >> Signed-off-by: Alexander Duyck > > > > So if and when virtio PFs can manage the VFs, then we can > > add a feature bit for that? > > Seems reasonable. > > Yes. If nothing else you may not even need a feature bit depending on > how things go. OTOH if the interface is changed in an incompatible way, and old Linux will attempt to drive the new device since there is no check. I think we should add a feature bit right away. > One of the reasons why Mark called out the > subvendor/subdevice was because that might be able to be used to > identify the specific hardware that is providing the SR-IOV feature so > in the future if it is added to virtio itself then you could exclude > devices like this by just limiting things based on subvendor/subdevice > IDs. > > > Also, I am guessing that hardware implementations will want > > to add things like stong memory barriers - I guess we > > will add new feature bits for that too down the road? > > That piece I don't have visibility into at this time. Perhaps Dan > might have more visibility into future plans on what this might need. > > Thanks. > > - Alex --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org