Hi All:
This series tries to add the support for control virtqueue in vDPA.
Control virtqueue is used by networking device for accepting various
commands from the driver. It's a must to support multiqueue and other
configurations.
When used by vhost-vDPA bus driver for VM, the control virtqueue
should be shadowed via userspace VMM (Qemu) instead of being assigned
directly to Guest. This is because Qemu needs to know the device state
in order to start and stop device correctly (e.g for Live Migration).
This requies to isolate the memory mapping for control virtqueue
presented by vhost-vDPA to prevent guest from accessing it directly.
To achieve this, vDPA introduce two new abstractions:
- address space: identified through address space id (ASID) and a set
of memory mapping in maintained
- virtqueue group: the minimal set of virtqueues that must share an
address space
Device needs to advertise the following attributes to vDPA:
- the number of address spaces supported in the device
- the number of virtqueue groups supported in the device
- the mappings from a specific virtqueue to its virtqueue groups
The mappings from virtqueue to virtqueue groups is fixed and defined
by vDPA device driver. E.g:
- For the device that has hardware ASID support, it can simply
advertise a per virtqueue virtqueue group.
- For the device that does not have hardware ASID support, it can
simply advertise a single virtqueue group that contains all
virtqueues. Or if it wants a software emulated control virtqueue, it
can advertise two virtqueue groups, one is for cvq, another is for
the rest virtqueues.
vDPA also allow to change the association between virtqueue group and
address space. So in the case of control virtqueue, userspace
VMM(Qemu) may use a dedicated address space for the control virtqueue
group to isolate the memory mapping.
The vhost/vhost-vDPA is also extend for the userspace to:
- query the number of virtqueue groups and address spaces supported by
the device
- query the virtqueue group for a specific virtqueue
- assocaite a virtqueue group with an address space
- send ASID based IOTLB commands
This will help userspace VMM(Qemu) to detect whether the control vq
could be supported and isolate memory mappings of control virtqueue
from the others.
To demonstrate the usage, vDPA simulator is extended to support
setting MAC address via a emulated control virtqueue.
Please review.
Changes since v1:
- Rebased the v1 patch series on vhost branch of MST vhost git repo
git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git/log/?h=vhost
- Updates to accommodate vdpa_sim changes from monolithic module in
kernel used v1 patch series to current modularized class (net, block)
based approach.
- Added new attributes (ngroups and nas) to "vdpasim_dev_attr" and
propagated them from vdpa_sim_net to vdpa_sim
- Widened the data-type for "asid" member of vhost_msg_v2 to __u32
to accommodate PASID
- Fixed the buildbot warnings
- Resolved all checkpatch.pl errors and warnings
- Tested both control and datapath with Xilinx Smartnic SN1000 series
device using QEMU implementing the Shadow virtqueue and support for
VQ groups and ASID available at:
github.com/eugpermar/qemu/releases/tag/vdpa_sw_live_migration.d%2F
asid_groups-v1.d%2F00
Changes since RFC:
- tweak vhost uAPI documentation
- switch to use device specific IOTLB really in patch 4
- tweak the commit log
- fix that ASID in vhost is claimed to be 32 actually but 16bit
actually
- fix use after free when using ASID with IOTLB batching requests
- switch to use Stefano's patch for having separated iov
- remove unused "used_as" variable
- fix the iotlb/asid checking in vhost_vdpa_unmap()
Thanks
Gautam Dawar (19):
vhost: move the backend feature bits to vhost_types.h
virtio-vdpa: don't set callback if virtio doesn't need it
vhost-vdpa: passing iotlb to IOMMU mapping helpers
vhost-vdpa: switch to use vhost-vdpa specific IOTLB
vdpa: introduce virtqueue groups
vdpa: multiple address spaces support
vdpa: introduce config operations for associating ASID to a virtqueue
group
vhost_iotlb: split out IOTLB initialization
vhost: support ASID in IOTLB API
vhost-vdpa: introduce asid based IOTLB
vhost-vdpa: introduce uAPI to get the number of virtqueue groups
vhost-vdpa: introduce uAPI to get the number of address spaces
vhost-vdpa: uAPI to get virtqueue group id
vhost-vdpa: introduce uAPI to set group ASID
vhost-vdpa: support ASID based IOTLB API
vdpa_sim: advertise VIRTIO_NET_F_MTU
vdpa_sim: factor out buffer completion logic
vdpa_sim: filter destination mac address
vdpasim: control virtqueue support
drivers/vdpa/ifcvf/ifcvf_main.c | 8 +-
drivers/vdpa/mlx5/net/mlx5_vnet.c | 11 +-
drivers/vdpa/vdpa.c | 5 +
drivers/vdpa/vdpa_sim/vdpa_sim.c | 100 ++++++++--
drivers/vdpa/vdpa_sim/vdpa_sim.h | 3 +
drivers/vdpa/vdpa_sim/vdpa_sim_net.c | 169 +++++++++++++----
drivers/vhost/iotlb.c | 23 ++-
drivers/vhost/vdpa.c | 272 +++++++++++++++++++++------
drivers/vhost/vhost.c | 23 ++-
drivers/vhost/vhost.h | 4 +-
drivers/virtio/virtio_vdpa.c | 2 +-
include/linux/vdpa.h | 46 ++++-
include/linux/vhost_iotlb.h | 2 +
include/uapi/linux/vhost.h | 25 ++-
include/uapi/linux/vhost_types.h | 11 +-
15 files changed, 566 insertions(+), 138 deletions(-)
--
2.25.0
