From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752949AbeDCS1s (ORCPT ); Tue, 3 Apr 2018 14:27:48 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:38634 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752785AbeDCS1p (ORCPT ); Tue, 3 Apr 2018 14:27:45 -0400 Date: Tue, 3 Apr 2018 21:27:43 +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: <20180403212503-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> <20180403161151-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 Tue, Apr 03, 2018 at 10:32:00AM -0700, Alexander Duyck wrote: > On Tue, Apr 3, 2018 at 6:12 AM, Michael S. Tsirkin wrote: > > 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. > > I'm not sure why you would need a feature bit. The capability is > controlled via PCI configuration space. If it is present the device > has the capability. If it is not then it does not. > > Basically if the PCI configuration space is not present then the sysfs > entries will not be spawned and nothing will attempt to use this > function. > > - ALex It's about compability with older guests which ignore the capability. The feature is thus helpful so host knows whether guest supports VFs. -- MSR From mboxrd@z Thu Jan 1 00:00:00 1970 From: mst@redhat.com (Michael S. Tsirkin) Date: Tue, 3 Apr 2018 21:27:43 +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> <20180403161151-mutt-send-email-mst@kernel.org> Message-ID: <20180403212503-mutt-send-email-mst@kernel.org> On Tue, Apr 03, 2018@10:32:00AM -0700, Alexander Duyck wrote: > On Tue, Apr 3, 2018@6:12 AM, Michael S. Tsirkin wrote: > > 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. > > I'm not sure why you would need a feature bit. The capability is > controlled via PCI configuration space. If it is present the device > has the capability. If it is not then it does not. > > Basically if the PCI configuration space is not present then the sysfs > entries will not be spawned and nothing will attempt to use this > function. > > - ALex It's about compability with older guests which ignore the capability. The feature is thus helpful so host knows whether guest supports VFs. -- MSR From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-dev-return-3710-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 98B4F5818F9D for ; Tue, 3 Apr 2018 11:27:56 -0700 (PDT) Date: Tue, 3 Apr 2018 21:27:43 +0300 From: "Michael S. Tsirkin" Message-ID: <20180403212503-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> <20180403161151-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 Tue, Apr 03, 2018 at 10:32:00AM -0700, Alexander Duyck wrote: > On Tue, Apr 3, 2018 at 6:12 AM, Michael S. Tsirkin wrote: > > 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. > > I'm not sure why you would need a feature bit. The capability is > controlled via PCI configuration space. If it is present the device > has the capability. If it is not then it does not. > > Basically if the PCI configuration space is not present then the sysfs > entries will not be spawned and nothing will attempt to use this > function. > > - ALex It's about compability with older guests which ignore the capability. The feature is thus helpful so host knows whether guest supports VFs. -- MSR --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org