From: "Michael S. Tsirkin" <mst@redhat.com>
To: Shahaf Shuler <shahafs@mellanox.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 16:25:23 -0500
Message-ID: <20200120162449-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <AM0PR0502MB3795C92485338180FC8059CFC3320@AM0PR0502MB3795.eurprd05.prod.outlook.com>
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...
> >
> > > > 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 index
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
2020-01-20 21:25 ` Michael S. Tsirkin [this message]
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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