From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Samudrala, Sridhar" Subject: Re: Re: [Qemu-devel] [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices... Date: Thu, 12 Jul 2018 21:20:41 -0400 Message-ID: <77823ff9-a02a-808b-e919-b4950a64ae3c@intel.com> References: <20180703095825.GC30904@rkaganb.sw.ru> <20180709130035.GA6271@rkaganb.sw.ru> <9136094e-a510-4201-7c71-d1c49226fa5f@oracle.com> <20180710045101-mutt-send-email-mst@kernel.org> <20180711115344.633eba9e.cohuck@redhat.com> <20180712133121.3b5f2bae.cohuck@redhat.com> <20180712235500-mutt-send-email-mst@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Cornelia Huck , si-wei liu , Roman Kagan , Venu Busireddy , Marcel Apfelbaum , virtio-dev@lists.oasis-open.org, qemu-devel@nongnu.org, Alexander Duyck , Netdev To: Siwei Liu , "Michael S. Tsirkin" Return-path: Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: In-Reply-To: Content-Language: en-US List-Id: netdev.vger.kernel.org On 7/12/2018 6:19 PM, Siwei Liu wrote: > On Thu, Jul 12, 2018 at 2:00 PM, Michael S. Tsirkin wrote: >> On Thu, Jul 12, 2018 at 01:52:53PM -0700, Siwei Liu wrote: >>> The definition is incomplete due to lack of spec. There's no "host" >>> part defined yet in the host-guest interface. If match by MAC is an >>> interface, the same must be done on the host(device) side as well, >>> which has been agreed not the way to go. However, I don't think that's >>> what the author intends to do by interpreting his QEMU patch - it >>> missed the other parts as well, such as the feature negotiation and >>> how it interacts with the paired device. >>> >>> What I said is that match by MAC is just a guest implementation that >>> one can change at any time. We now have the group ID on QEMU, why >>> still sticking to matching by MAC? It shoulnd't be a host-guest >>> interface in the first place anyway. >> I think that match by MAC is a simple portable way to match devices. >> E.g. it will work seamlessly with niche things like zPCI. However > That's a good point. I'm not sure if it's a valid assumption that zPCI > should always use the same MAC address as that of virtio. Someone > who's more familiar with the use case may decide and work on that. It > means VFIO device has to take in the MAC address as an identifier to > the "-device vfio-pci,.." QEMU option. I think there's no point to > match device using group ID in QEMU while using MAC in the guest. > Based on that assumption, I'd go with making VIRTIO_NET_F_STANDBY to > match device based on group ID, while someone may come up with another > feature bit later, say VIRTIO_NET_F_STANDBY_BY_MAC when its QEMU > support is available. Would it make sense? VIRTIO_NET_F_STANDBY as defined in the guest virtio_net driver supports match by MAC address. I think we should add support for this feature bit in QEMU. If submitting a patch to update the spec is a pre-requisite to add this feature bit to QEMU, i can do that. As far as i understand, group id patches to QEMU are still under review. Matching by group ID can be another feature bit that could support matching by group id as well as MAC. > -Siwei > >> there are other niche use-cases that aren't addressed by match by MAC >> such as PF pass-through as a primary, and the pci bridge trick addresses >> that at cost of some portability. >> >> So I see no issues supporting both mechanisms, but others on the TC >> might feel differently. >> >> -- >> MST From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55689) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fdmlS-0008IV-Hk for qemu-devel@nongnu.org; Thu, 12 Jul 2018 21:20:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fdmlP-0002IO-ED for qemu-devel@nongnu.org; Thu, 12 Jul 2018 21:20:54 -0400 Received: from mga17.intel.com ([192.55.52.151]:34609) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fdmlP-0002Dp-3k for qemu-devel@nongnu.org; Thu, 12 Jul 2018 21:20:51 -0400 References: <20180703095825.GC30904@rkaganb.sw.ru> <20180709130035.GA6271@rkaganb.sw.ru> <9136094e-a510-4201-7c71-d1c49226fa5f@oracle.com> <20180710045101-mutt-send-email-mst@kernel.org> <20180711115344.633eba9e.cohuck@redhat.com> <20180712133121.3b5f2bae.cohuck@redhat.com> <20180712235500-mutt-send-email-mst@kernel.org> From: "Samudrala, Sridhar" Message-ID: <77823ff9-a02a-808b-e919-b4950a64ae3c@intel.com> Date: Thu, 12 Jul 2018 21:20:41 -0400 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Subject: Re: [Qemu-devel] [virtio-dev] Re: [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices... List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Siwei Liu , "Michael S. Tsirkin" Cc: Cornelia Huck , si-wei liu , Roman Kagan , Venu Busireddy , Marcel Apfelbaum , virtio-dev@lists.oasis-open.org, qemu-devel@nongnu.org, Alexander Duyck , Netdev On 7/12/2018 6:19 PM, Siwei Liu wrote: > On Thu, Jul 12, 2018 at 2:00 PM, Michael S. Tsirkin wrote: >> On Thu, Jul 12, 2018 at 01:52:53PM -0700, Siwei Liu wrote: >>> The definition is incomplete due to lack of spec. There's no "host" >>> part defined yet in the host-guest interface. If match by MAC is an >>> interface, the same must be done on the host(device) side as well, >>> which has been agreed not the way to go. However, I don't think that's >>> what the author intends to do by interpreting his QEMU patch - it >>> missed the other parts as well, such as the feature negotiation and >>> how it interacts with the paired device. >>> >>> What I said is that match by MAC is just a guest implementation that >>> one can change at any time. We now have the group ID on QEMU, why >>> still sticking to matching by MAC? It shoulnd't be a host-guest >>> interface in the first place anyway. >> I think that match by MAC is a simple portable way to match devices. >> E.g. it will work seamlessly with niche things like zPCI. However > That's a good point. I'm not sure if it's a valid assumption that zPCI > should always use the same MAC address as that of virtio. Someone > who's more familiar with the use case may decide and work on that. It > means VFIO device has to take in the MAC address as an identifier to > the "-device vfio-pci,.." QEMU option. I think there's no point to > match device using group ID in QEMU while using MAC in the guest. > Based on that assumption, I'd go with making VIRTIO_NET_F_STANDBY to > match device based on group ID, while someone may come up with another > feature bit later, say VIRTIO_NET_F_STANDBY_BY_MAC when its QEMU > support is available. Would it make sense? VIRTIO_NET_F_STANDBY as defined in the guest virtio_net driver supports match by MAC address. I think we should add support for this feature bit in QEMU. If submitting a patch to update the spec is a pre-requisite to add this feature bit to QEMU, i can do that. As far as i understand, group id patches to QEMU are still under review. Matching by group ID can be another feature bit that could support matching by group id as well as MAC. > -Siwei > >> there are other niche use-cases that aren't addressed by match by MAC >> such as PF pass-through as a primary, and the pci bridge trick addresses >> that at cost of some portability. >> >> So I see no issues supporting both mechanisms, but others on the TC >> might feel differently. >> >> -- >> MST From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-dev-return-4701-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 [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 135B6985507 for ; Fri, 13 Jul 2018 01:20:48 +0000 (UTC) References: <20180703095825.GC30904@rkaganb.sw.ru> <20180709130035.GA6271@rkaganb.sw.ru> <9136094e-a510-4201-7c71-d1c49226fa5f@oracle.com> <20180710045101-mutt-send-email-mst@kernel.org> <20180711115344.633eba9e.cohuck@redhat.com> <20180712133121.3b5f2bae.cohuck@redhat.com> <20180712235500-mutt-send-email-mst@kernel.org> From: "Samudrala, Sridhar" Message-ID: <77823ff9-a02a-808b-e919-b4950a64ae3c@intel.com> Date: Thu, 12 Jul 2018 21:20:41 -0400 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Subject: Re: [virtio-dev] Re: [Qemu-devel] [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices... To: Siwei Liu , "Michael S. Tsirkin" Cc: Cornelia Huck , si-wei liu , Roman Kagan , Venu Busireddy , Marcel Apfelbaum , virtio-dev@lists.oasis-open.org, qemu-devel@nongnu.org, Alexander Duyck , Netdev List-ID: On 7/12/2018 6:19 PM, Siwei Liu wrote: > On Thu, Jul 12, 2018 at 2:00 PM, Michael S. Tsirkin wrote: >> On Thu, Jul 12, 2018 at 01:52:53PM -0700, Siwei Liu wrote: >>> The definition is incomplete due to lack of spec. There's no "host" >>> part defined yet in the host-guest interface. If match by MAC is an >>> interface, the same must be done on the host(device) side as well, >>> which has been agreed not the way to go. However, I don't think that's >>> what the author intends to do by interpreting his QEMU patch - it >>> missed the other parts as well, such as the feature negotiation and >>> how it interacts with the paired device. >>> >>> What I said is that match by MAC is just a guest implementation that >>> one can change at any time. We now have the group ID on QEMU, why >>> still sticking to matching by MAC? It shoulnd't be a host-guest >>> interface in the first place anyway. >> I think that match by MAC is a simple portable way to match devices. >> E.g. it will work seamlessly with niche things like zPCI. However > That's a good point. I'm not sure if it's a valid assumption that zPCI > should always use the same MAC address as that of virtio. Someone > who's more familiar with the use case may decide and work on that. It > means VFIO device has to take in the MAC address as an identifier to > the "-device vfio-pci,.." QEMU option. I think there's no point to > match device using group ID in QEMU while using MAC in the guest. > Based on that assumption, I'd go with making VIRTIO_NET_F_STANDBY to > match device based on group ID, while someone may come up with another > feature bit later, say VIRTIO_NET_F_STANDBY_BY_MAC when its QEMU > support is available. Would it make sense? VIRTIO_NET_F_STANDBY as defined in the guest virtio_net driver supports match by MAC address. I think we should add support for this feature bit in QEMU. If submitting a patch to update the spec is a pre-requisite to add this feature bit to QEMU, i can do that. As far as i understand, group id patches to QEMU are still under review. Matching by group ID can be another feature bit that could support matching by group id as well as MAC. > -Siwei > >> there are other niche use-cases that aren't addressed by match by MAC >> such as PF pass-through as a primary, and the pci bridge trick addresses >> that at cost of some portability. >> >> So I see no issues supporting both mechanisms, but others on the TC >> might feel differently. >> >> -- >> MST --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org