From: "Michael S. Tsirkin" <mst@redhat.com>
To: "Eugenio Pérez" <eperezma@redhat.com>
Cc: Parav Pandit <parav@mellanox.com>,
Juan Quintela <quintela@redhat.com>,
Jason Wang <jasowang@redhat.com>,
Markus Armbruster <armbru@redhat.com>,
qemu-devel@nongnu.org, Harpreet Singh Anand <hanand@xilinx.com>,
Xiao W Wang <xiao.w.wang@intel.com>,
Stefan Hajnoczi <stefanha@redhat.com>,
Eli Cohen <eli@mellanox.com>,
virtualization@lists.linux-foundation.org,
Michael Lilja <ml@napatech.com>,
Stefano Garzarella <sgarzare@redhat.com>
Subject: Re: [RFC v3 00/29] vDPA software assisted live migration
Date: Mon, 24 May 2021 05:38:05 -0400 [thread overview]
Message-ID: <20210524053144-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20210519162903.1172366-1-eperezma@redhat.com>
On Wed, May 19, 2021 at 06:28:34PM +0200, Eugenio Pérez wrote:
> Commit 17 introduces the buffer forwarding. Previous one are for
> preparations again, and laters are for enabling some obvious
> optimizations. However, it needs the vdpa device to be able to map
> every IOVA space, and some vDPA devices are not able to do so. Checking
> of this is added in previous commits.
That might become a significant limitation. And it worries me that
this is such a big patchset which might yet take a while to get
finalized.
I have an idea: how about as a first step we implement a transparent
switch from vdpa to a software virtio in QEMU or a software vhost in
kernel?
This will give us live migration quickly with performance comparable
to failover but without dependance on guest cooperation.
Next step could be driving vdpa from userspace while still copying
packets to a pre-registered buffer.
Finally your approach will be a performance optimization for devices
that support arbitrary IOVA.
Thoughts?
--
MST
next prev parent reply other threads:[~2021-05-24 9:38 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-19 16:28 [RFC v3 00/29] vDPA software assisted live migration Eugenio Pérez
2021-05-19 16:28 ` [RFC v3 01/29] virtio: Add virtio_queue_is_host_notifier_enabled Eugenio Pérez
2021-05-19 16:28 ` [RFC v3 02/29] vhost: Save masked_notifier state Eugenio Pérez
2021-05-19 16:28 ` [RFC v3 03/29] vhost: Add VhostShadowVirtqueue Eugenio Pérez
2021-05-19 16:28 ` [RFC v3 04/29] vhost: Add x-vhost-enable-shadow-vq qmp Eugenio Pérez
2021-05-21 7:05 ` Markus Armbruster
2021-05-24 7:13 ` Eugenio Perez Martin
2021-06-08 14:23 ` Markus Armbruster
2021-06-08 15:26 ` Eugenio Perez Martin
2021-06-09 11:46 ` Markus Armbruster
2021-06-09 14:06 ` Eugenio Perez Martin
2021-05-19 16:28 ` [RFC v3 05/29] virtio: Add VIRTIO_F_QUEUE_STATE Eugenio Pérez
2021-05-19 16:28 ` [RFC v3 06/29] virtio-net: Honor VIRTIO_CONFIG_S_DEVICE_STOPPED Eugenio Pérez
2021-05-26 1:06 ` Jason Wang
2021-05-26 1:10 ` Jason Wang
2021-06-01 7:13 ` Eugenio Perez Martin
2021-06-03 3:12 ` Jason Wang
2021-05-19 16:28 ` [RFC v3 07/29] vhost: Route guest->host notification through shadow virtqueue Eugenio Pérez
2021-05-19 16:28 ` [RFC v3 08/29] vhost: Route host->guest " Eugenio Pérez
2021-05-19 16:28 ` [RFC v3 09/29] vhost: Avoid re-set masked notifier in shadow vq Eugenio Pérez
2021-05-19 16:28 ` [RFC v3 10/29] virtio: Add vhost_shadow_vq_get_vring_addr Eugenio Pérez
2021-05-19 16:28 ` [RFC v3 11/29] vhost: Add vhost_vring_pause operation Eugenio Pérez
2021-05-19 16:28 ` [RFC v3 12/29] vhost: add vhost_kernel_vring_pause Eugenio Pérez
2021-05-19 16:28 ` [RFC v3 13/29] vhost: Add vhost_get_iova_range operation Eugenio Pérez
2021-05-26 1:14 ` Jason Wang
2021-05-26 17:49 ` Eugenio Perez Martin
2021-05-27 4:51 ` Jason Wang
2021-06-01 7:17 ` Eugenio Perez Martin
2021-06-03 3:13 ` Jason Wang
2021-05-19 16:28 ` [RFC v3 14/29] vhost: add vhost_has_limited_iova_range Eugenio Pérez
2021-05-19 16:28 ` [RFC v3 15/29] vhost: Add enable_custom_iommu to VhostOps Eugenio Pérez
2021-05-31 9:01 ` Jason Wang
2021-06-01 7:49 ` Eugenio Perez Martin
2021-05-19 16:28 ` [RFC v3 16/29] vhost-vdpa: Add vhost_vdpa_enable_custom_iommu Eugenio Pérez
2021-05-19 16:28 ` [RFC v3 17/29] vhost: Shadow virtqueue buffers forwarding Eugenio Pérez
2021-06-02 9:50 ` Jason Wang
2021-06-02 17:18 ` Eugenio Perez Martin
2021-06-03 3:34 ` Jason Wang
2021-06-04 8:37 ` Eugenio Perez Martin
2021-05-19 16:28 ` [RFC v3 18/29] vhost: Use vhost_enable_custom_iommu to unmap everything if available Eugenio Pérez
2021-05-19 16:28 ` [RFC v3 19/29] vhost: Check for device VRING_USED_F_NO_NOTIFY at shadow virtqueue kick Eugenio Pérez
2021-05-19 16:28 ` [RFC v3 20/29] vhost: Use VRING_AVAIL_F_NO_INTERRUPT at device call on shadow virtqueue Eugenio Pérez
2021-05-19 16:28 ` [RFC v3 21/29] vhost: Add VhostIOVATree Eugenio Pérez
2021-05-31 9:40 ` Jason Wang
2021-06-01 8:15 ` Eugenio Perez Martin
2021-07-14 3:04 ` Jason Wang
2021-07-14 6:54 ` Eugenio Perez Martin
2021-07-14 9:14 ` Eugenio Perez Martin
2021-07-14 9:33 ` Jason Wang
2021-05-19 16:28 ` [RFC v3 22/29] vhost: Add iova_rev_maps_find_iova to IOVAReverseMaps Eugenio Pérez
2021-05-19 16:28 ` [RFC v3 23/29] vhost: Use a tree to store memory mappings Eugenio Pérez
2021-05-19 16:28 ` [RFC v3 24/29] vhost: Add iova_rev_maps_alloc Eugenio Pérez
2021-05-19 16:28 ` [RFC v3 25/29] vhost: Add custom IOTLB translations to SVQ Eugenio Pérez
2021-06-02 9:51 ` Jason Wang
2021-06-02 17:51 ` Eugenio Perez Martin
2021-06-03 3:39 ` Jason Wang
2021-06-04 9:07 ` Eugenio Perez Martin
2021-05-19 16:29 ` [RFC v3 26/29] vhost: Map in vdpa-dev Eugenio Pérez
2021-05-19 16:29 ` [RFC v3 27/29] vhost-vdpa: Implement vhost_vdpa_vring_pause operation Eugenio Pérez
2021-05-19 16:29 ` [RFC v3 28/29] vhost-vdpa: never map with vDPA listener Eugenio Pérez
2021-05-19 16:29 ` [RFC v3 29/29] vhost: Start vhost-vdpa SVQ directly Eugenio Pérez
2021-05-24 9:38 ` Michael S. Tsirkin [this message]
2021-05-24 10:37 ` [RFC v3 00/29] vDPA software assisted live migration Eugenio Perez Martin
2021-05-24 11:29 ` Michael S. Tsirkin
2021-07-19 14:13 ` Stefan Hajnoczi
2021-05-25 0:09 ` Jason Wang
2021-06-02 9:59 ` Jason Wang
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