From: Shahaf Shuler <shahafs@mellanox.com> To: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Gunthorpe <jgg@mellanox.com>, Jason Wang <jasowang@redhat.com>, Rob Miller <rob.miller@broadcom.com>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "kvm@vger.kernel.org" <kvm@vger.kernel.org>, "virtualization@lists.linux-foundation.org" <virtualization@lists.linux-foundation.org>, Netdev <netdev@vger.kernel.org>, "Bie, Tiwei" <tiwei.bie@intel.com>, "maxime.coquelin@redhat.com" <maxime.coquelin@redhat.com>, "Liang, Cunming" <cunming.liang@intel.com>, "Wang, Zhihong" <zhihong.wang@intel.com>, "Wang, Xiao W" <xiao.w.wang@intel.com>, "haotian.wang@sifive.com" <haotian.wang@sifive.com>, "Zhu, Lingshan" <lingshan.zhu@intel.com>, "eperezma@redhat.com" <eperezma@redhat.com>, "lulu@redhat.com" <lulu@redhat.com>, Parav Pandit <parav@mellanox.com>, "Tian, Kevin" <kevin.tian@intel.com>, "stefanha@redhat.com" <stefanha@redhat.com>, "rdunlap@infradead.org" <rdunlap@infradead.org>, "hch@infradead.org" <hch@infradead.org>, Ariel Adam <aadam@redhat.com>, "jakub.kicinski@netronome.com" <jakub.kicinski@netronome.com>, Jiri Pirko <jiri@mellanox.com>, "hanand@xilinx.com" <hanand@xilinx.com>, "mhabets@solarflare.com" <mhabets@solarflare.com> Subject: RE: [PATCH 3/5] vDPA: introduce vDPA bus Date: Mon, 20 Jan 2020 21:47:18 +0000 [thread overview] Message-ID: <AM0PR0502MB3795A7BE7F434964D6102517C3320@AM0PR0502MB3795.eurprd05.prod.outlook.com> (raw) In-Reply-To: <20200120162449-mutt-send-email-mst@kernel.org> Monday, January 20, 2020 11:25 PM, Michael S. Tsirkin: > Subject: Re: [PATCH 3/5] vDPA: introduce vDPA bus > > On Mon, Jan 20, 2020 at 08:51:43PM +0000, Shahaf Shuler wrote: > > Monday, January 20, 2020 7:50 PM, Jason Gunthorpe: > > > Subject: Re: [PATCH 3/5] vDPA: introduce vDPA bus > > > > > > On Mon, Jan 20, 2020 at 04:43:53PM +0800, Jason Wang wrote: > > > > This is similar to the design of platform IOMMU part of > > > > vhost-vdpa. We decide to send diffs to platform IOMMU there. If > > > > it's ok to do that in driver, we can replace set_map with incremental API > like map()/unmap(). > > > > > > > > Then driver need to maintain rbtree itself. > > > > > > I think we really need to see two modes, one where there is a fixed > > > translation without dynamic vIOMMU driven changes and one that > > > supports vIOMMU. > > > > > > There are different optimization goals in the drivers for these two > > > configurations. > > > > +1. > > It will be best to have one API for static config (i.e. mapping can be > > set only before virtio device gets active), and one API for dynamic > > changes that can be set after the virtio device is active. > > Frankly I don't see when we'd use the static one. > Memory hotplug is enabled for most guests... The fact memory hotplug is enabled doesn't necessarily means there is not cold-plugged memory on the hot plugged slots. So your claim is majority of guests are deployed w/o any cold-plugged memory? > > > > > > > > > If the first one, then I think memory hotplug is a heavy flow > > > > > regardless. Do you think the extra cycles for the tree traverse > > > > > will be visible in any way? > > > > > > > > I think if the driver can pause the DMA during the time for > > > > setting up new mapping, it should be fine. > > > > > > This is very tricky for any driver if the mapping change hits the > > > virtio rings. :( > > > > > > Even a IOMMU using driver is going to have problems with that.. > > > > > > Jason
WARNING: multiple messages have this Message-ID (diff)
From: Shahaf Shuler <shahafs@mellanox.com> To: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Gunthorpe <jgg@mellanox.com>, Jason Wang <jasowang@redhat.com>, Rob Miller <rob.miller@broadcom.com>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "kvm@vger.kernel.org" <kvm@vger.kernel.org>, "virtualization@lists.linux-foundation.org" <virtualization@lists.linux-foundation.org>, Netdev <netdev@vger.kernel.org>, "Bie, Tiwei" <tiwei.bie@intel.com>, "maxime.coquelin@redhat.com" <maxime.coquelin@redhat.com>, "Liang, Cunming" <cunming.liang@intel.com>, "Wang, Zhihong" <zhihong.wang@intel.com>, "Wang, Xiao W" <xiao.w.wang@intel.com>, "haotian.wang@sifive.com" <haotian.wang@sifive.com>, "Zhu, Lingshan" <lingshan.zhu@intel.com>, "eperezma@redhat.com" <eperezma@redhat.com>, "lulu@redhat.com" <lulu@redhat.com>, Parav Pandit <parav@mel> Subject: RE: [PATCH 3/5] vDPA: introduce vDPA bus Date: Mon, 20 Jan 2020 21:47:18 +0000 [thread overview] Message-ID: <AM0PR0502MB3795A7BE7F434964D6102517C3320@AM0PR0502MB3795.eurprd05.prod.outlook.com> (raw) In-Reply-To: <20200120162449-mutt-send-email-mst@kernel.org> Monday, January 20, 2020 11:25 PM, Michael S. Tsirkin: > Subject: Re: [PATCH 3/5] vDPA: introduce vDPA bus > > On Mon, Jan 20, 2020 at 08:51:43PM +0000, Shahaf Shuler wrote: > > Monday, January 20, 2020 7:50 PM, Jason Gunthorpe: > > > Subject: Re: [PATCH 3/5] vDPA: introduce vDPA bus > > > > > > On Mon, Jan 20, 2020 at 04:43:53PM +0800, Jason Wang wrote: > > > > This is similar to the design of platform IOMMU part of > > > > vhost-vdpa. We decide to send diffs to platform IOMMU there. If > > > > it's ok to do that in driver, we can replace set_map with incremental API > like map()/unmap(). > > > > > > > > Then driver need to maintain rbtree itself. > > > > > > I think we really need to see two modes, one where there is a fixed > > > translation without dynamic vIOMMU driven changes and one that > > > supports vIOMMU. > > > > > > There are different optimization goals in the drivers for these two > > > configurations. > > > > +1. > > It will be best to have one API for static config (i.e. mapping can be > > set only before virtio device gets active), and one API for dynamic > > changes that can be set after the virtio device is active. > > Frankly I don't see when we'd use the static one. > Memory hotplug is enabled for most guests... The fact memory hotplug is enabled doesn't necessarily means there is not cold-plugged memory on the hot plugged slots. So your claim is majority of guests are deployed w/o any cold-plugged memory? > > > > > > > > > If the first one, then I think memory hotplug is a heavy flow > > > > > regardless. Do you think the extra cycles for the tree traverse > > > > > will be visible in any way? > > > > > > > > I think if the driver can pause the DMA during the time for > > > > setting up new mapping, it should be fine. > > > > > > This is very tricky for any driver if the mapping change hits the > > > virtio rings. :( > > > > > > Even a IOMMU using driver is going to have problems with that.. > > > > > > Jason
next prev parent reply other threads:[~2020-01-20 21:48 UTC|newest] Thread overview: 141+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-01-16 12:42 [PATCH 0/5] vDPA support Jason Wang 2020-01-16 12:42 ` [PATCH 1/5] vhost: factor out IOTLB Jason Wang 2020-01-17 4:14 ` Randy Dunlap 2020-01-17 9:34 ` Jason Wang 2020-01-18 0:01 ` kbuild test robot 2020-01-18 0:01 ` kbuild test robot 2020-01-18 0:01 ` kbuild test robot 2020-01-18 0:40 ` kbuild test robot 2020-01-18 0:40 ` kbuild test robot 2020-01-18 0:40 ` kbuild test robot 2020-01-16 12:42 ` [PATCH 2/5] vringh: IOTLB support Jason Wang 2020-01-17 21:54 ` kbuild test robot 2020-01-17 21:54 ` kbuild test robot 2020-01-17 21:54 ` kbuild test robot 2020-01-17 22:33 ` kbuild test robot 2020-01-17 22:33 ` kbuild test robot 2020-01-17 22:33 ` kbuild test robot 2020-01-16 12:42 ` [PATCH 3/5] vDPA: introduce vDPA bus Jason Wang 2020-01-16 15:22 ` Jason Gunthorpe 2020-01-16 15:22 ` Jason Gunthorpe 2020-01-17 3:03 ` Jason Wang 2020-01-17 3:03 ` Jason Wang 2020-01-17 13:54 ` Jason Gunthorpe 2020-01-17 13:54 ` Jason Gunthorpe 2020-01-20 7:50 ` Jason Wang 2020-01-20 7:50 ` Jason Wang 2020-01-20 12:17 ` Michael S. Tsirkin 2020-01-20 12:17 ` Michael S. Tsirkin 2020-01-20 17:50 ` Jason Gunthorpe 2020-01-20 17:50 ` Jason Gunthorpe 2020-01-20 21:56 ` Michael S. Tsirkin 2020-01-20 21:56 ` Michael S. Tsirkin 2020-01-21 14:12 ` Jason Gunthorpe 2020-01-21 14:12 ` Jason Gunthorpe 2020-01-21 14:15 ` Michael S. Tsirkin 2020-01-21 14:15 ` Michael S. Tsirkin 2020-01-21 14:16 ` Jason Gunthorpe 2020-01-21 14:16 ` Jason Gunthorpe 2020-01-21 8:40 ` Tian, Kevin 2020-01-21 8:40 ` Tian, Kevin 2020-01-21 9:41 ` Jason Wang 2020-01-21 9:41 ` Jason Wang 2020-01-17 4:16 ` Randy Dunlap 2020-01-17 9:34 ` Jason Wang 2020-01-17 12:13 ` Michael S. Tsirkin 2020-01-17 13:52 ` Jason Wang 2020-01-17 14:12 ` Rob Miller via Virtualization 2020-01-19 9:07 ` Shahaf Shuler 2020-01-19 9:07 ` Shahaf Shuler 2020-01-19 9:59 ` Michael S. Tsirkin 2020-01-19 9:59 ` Michael S. Tsirkin 2020-01-20 8:44 ` Jason Wang 2020-01-20 8:44 ` Jason Wang 2020-01-20 12:09 ` Michael S. Tsirkin 2020-01-20 12:09 ` Michael S. Tsirkin 2020-01-21 3:32 ` Jason Wang 2020-01-21 3:32 ` Jason Wang 2020-01-20 8:43 ` Jason Wang 2020-01-20 8:43 ` Jason Wang 2020-01-20 17:49 ` Jason Gunthorpe 2020-01-20 17:49 ` Jason Gunthorpe 2020-01-20 20:51 ` Shahaf Shuler 2020-01-20 20:51 ` Shahaf Shuler 2020-01-20 21:25 ` Michael S. Tsirkin 2020-01-20 21:25 ` Michael S. Tsirkin 2020-01-20 21:47 ` Shahaf Shuler [this message] 2020-01-20 21:47 ` Shahaf Shuler 2020-01-20 21:59 ` Michael S. Tsirkin 2020-01-20 21:59 ` Michael S. Tsirkin 2020-01-21 6:01 ` Shahaf Shuler 2020-01-21 6:01 ` Shahaf Shuler 2020-01-21 7:57 ` Jason Wang 2020-01-21 7:57 ` Jason Wang 2020-01-21 14:07 ` Jason Gunthorpe 2020-01-21 14:07 ` Jason Gunthorpe 2020-01-21 14:16 ` Michael S. Tsirkin 2020-01-21 14:16 ` Michael S. Tsirkin 2020-01-20 21:48 ` Michael S. Tsirkin 2020-01-20 21:48 ` Michael S. Tsirkin 2020-01-21 4:00 ` Jason Wang 2020-01-21 4:00 ` Jason Wang 2020-01-21 5:47 ` Michael S. Tsirkin 2020-01-21 5:47 ` Michael S. Tsirkin 2020-01-21 8:00 ` Jason Wang 2020-01-21 8:00 ` Jason Wang 2020-01-21 8:15 ` Michael S. Tsirkin 2020-01-21 8:15 ` Michael S. Tsirkin 2020-01-21 8:35 ` Jason Wang 2020-01-21 8:35 ` Jason Wang 2020-01-21 11:09 ` Shahaf Shuler 2020-01-21 11:09 ` Shahaf Shuler 2020-01-22 6:36 ` Jason Wang 2020-01-22 6:36 ` Jason Wang 2020-01-21 14:05 ` Jason Gunthorpe 2020-01-21 14:05 ` Jason Gunthorpe 2020-01-21 14:17 ` Michael S. Tsirkin 2020-01-21 14:17 ` Michael S. Tsirkin 2020-01-22 6:18 ` Jason Wang 2020-01-22 6:18 ` Jason Wang 2020-01-20 8:19 ` Jason Wang 2020-01-20 8:19 ` Jason Wang 2020-01-16 12:42 ` [PATCH 4/5] virtio: introduce a vDPA based transport Jason Wang 2020-01-16 15:38 ` Jason Gunthorpe 2020-01-16 15:38 ` Jason Gunthorpe 2020-01-17 9:32 ` Jason Wang 2020-01-17 9:32 ` Jason Wang 2020-01-17 14:00 ` Jason Gunthorpe 2020-01-17 14:00 ` Jason Gunthorpe 2020-01-20 7:52 ` Jason Wang 2020-01-20 7:52 ` Jason Wang 2020-01-17 4:10 ` Randy Dunlap 2020-01-16 12:42 ` [PATCH 5/5] vdpasim: vDPA device simulator Jason Wang 2020-01-16 15:47 ` Jason Gunthorpe 2020-01-16 15:47 ` Jason Gunthorpe 2020-01-17 9:32 ` Jason Wang 2020-01-17 9:32 ` Jason Wang 2020-01-17 14:10 ` Jason Gunthorpe 2020-01-17 14:10 ` Jason Gunthorpe 2020-01-20 8:01 ` Jason Wang 2020-01-20 8:01 ` Jason Wang 2020-02-04 4:19 ` Jason Wang 2020-02-04 4:19 ` Jason Wang 2020-01-17 4:12 ` Randy Dunlap 2020-01-17 9:35 ` Jason Wang 2020-01-18 18:18 ` kbuild test robot 2020-01-18 18:18 ` kbuild test robot 2020-01-18 18:18 ` kbuild test robot 2020-01-28 3:32 ` Dan Carpenter 2020-01-28 3:32 ` Dan Carpenter 2020-01-28 3:32 ` Dan Carpenter 2020-01-28 3:32 ` Dan Carpenter 2020-02-04 4:07 ` Jason Wang 2020-02-04 4:07 ` Jason Wang 2020-02-04 8:21 ` Zhu Lingshan 2020-02-04 8:28 ` Jason Wang 2020-02-04 12:52 ` Jason Gunthorpe 2020-02-05 3:14 ` Jason Wang 2020-01-21 8:44 ` [PATCH 0/5] vDPA support Tian, Kevin 2020-01-21 8:44 ` Tian, Kevin 2020-01-21 9:39 ` Jason Wang 2020-01-21 9:39 ` Jason Wang
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