From: Shahaf Shuler <shahafs@mellanox.com>
To: Jason Gunthorpe <jgg@mellanox.com>, Jason Wang <jasowang@redhat.com>
Cc: Rob Miller <rob.miller@broadcom.com>,
"Michael S. Tsirkin" <mst@redhat.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 20:51:43 +0000 [thread overview]
Message-ID: <AM0PR0502MB3795C92485338180FC8059CFC3320@AM0PR0502MB3795.eurprd05.prod.outlook.com> (raw)
In-Reply-To: <20200120174933.GB3891@mellanox.com>
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.
>
> > > 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 20:52 UTC|newest]
Thread overview: 76+ 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 0:40 ` 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 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
2020-01-17 3:03 ` Jason Wang
2020-01-17 13:54 ` Jason Gunthorpe
2020-01-20 7:50 ` Jason Wang
2020-01-20 12:17 ` Michael S. Tsirkin
2020-01-20 17:50 ` Jason Gunthorpe
2020-01-20 21:56 ` Michael S. Tsirkin
2020-01-21 14:12 ` Jason Gunthorpe
2020-01-21 14:15 ` Michael S. Tsirkin
2020-01-21 14:16 ` Jason Gunthorpe
2020-01-21 8:40 ` Tian, Kevin
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
[not found] ` <CAJPjb1+fG9L3=iKbV4Vn13VwaeDZZdcfBPvarogF_Nzhk+FnKg@mail.gmail.com>
2020-01-19 9:07 ` Shahaf Shuler
2020-01-19 9:59 ` Michael S. Tsirkin
2020-01-20 8:44 ` Jason Wang
2020-01-20 12:09 ` Michael S. Tsirkin
2020-01-21 3:32 ` Jason Wang
2020-01-20 8:43 ` Jason Wang
2020-01-20 17:49 ` Jason Gunthorpe
2020-01-20 20:51 ` Shahaf Shuler [this message]
2020-01-20 21:25 ` Michael S. Tsirkin
2020-01-20 21:47 ` Shahaf Shuler
2020-01-20 21:59 ` Michael S. Tsirkin
2020-01-21 6:01 ` Shahaf Shuler
2020-01-21 7:57 ` Jason Wang
2020-01-21 14:07 ` Jason Gunthorpe
2020-01-21 14:16 ` Michael S. Tsirkin
2020-01-20 21:48 ` Michael S. Tsirkin
2020-01-21 4:00 ` Jason Wang
2020-01-21 5:47 ` Michael S. Tsirkin
2020-01-21 8:00 ` Jason Wang
2020-01-21 8:15 ` Michael S. Tsirkin
2020-01-21 8:35 ` Jason Wang
2020-01-21 11:09 ` Shahaf Shuler
2020-01-22 6:36 ` Jason Wang
2020-01-21 14:05 ` Jason Gunthorpe
2020-01-21 14:17 ` Michael S. Tsirkin
2020-01-22 6:18 ` 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
2020-01-17 9:32 ` Jason Wang
2020-01-17 14:00 ` Jason Gunthorpe
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
2020-01-17 9:32 ` Jason Wang
2020-01-17 14:10 ` Jason Gunthorpe
2020-01-20 8:01 ` 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
2020-01-28 3:32 ` Dan Carpenter
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 9:39 ` Jason Wang
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