kernel/linux.git/include/uapi/linux/vhost.h, branch v6.6.131

vhost: Allow worker switching while work is queueing

2023-07-03T16:15:14+00:00

This patch drops the requirement that we can only switch workers if work has not been queued by using RCU for the vq based queueing paths and a mutex for the device wide flush. We can also use this to support SIGKILL properly in the future where we should exit almost immediately after getting that signal. With this patch, when get_signal returns true, we can set the vq->worker to NULL and do a synchronize_rcu to prevent new work from being queued to the vhost_task that has been killed. Signed-off-by: Mike Christie Message-Id: <20230626232307.97930-18-michael.christie@oracle.com> Signed-off-by: Michael S. Tsirkin

vhost: allow userspace to create workers

2023-07-03T16:15:14+00:00

For vhost-scsi with 3 vqs or more and a workload that tries to use them in parallel like: fio --filename=/dev/sdb --direct=1 --rw=randrw --bs=4k \ --ioengine=libaio --iodepth=128 --numjobs=3 the single vhost worker thread will become a bottlneck and we are stuck at around 500K IOPs no matter how many jobs, virtqueues, and CPUs are used. To better utilize virtqueues and available CPUs, this patch allows userspace to create workers and bind them to vqs. You can have N workers per dev and also share N workers with M vqs on that dev. This patch adds the interface related code and the next patch will hook vhost-scsi into it. The patches do not try to hook net and vsock into the interface because: 1. multiple workers don't seem to help vsock. The problem is that with only 2 virtqueues we never fully use the existing worker when doing bidirectional tests. This seems to match vhost-scsi where we don't see the worker as a bottleneck until 3 virtqueues are used. 2. net already has a way to use multiple workers. Signed-off-by: Mike Christie Message-Id: <20230626232307.97930-16-michael.christie@oracle.com> Signed-off-by: Michael S. Tsirkin

vhost-vdpa: uAPI to resume the device

2023-02-21T00:26:56+00:00

This new ioctl adds support for resuming the device from userspace. This is required when trying to restore the device in a functioning state after it's been suspended. It is already possible to reset a suspended device, but that means the device must be reconfigured and all the IOMMU/IOTLB mappings must be recreated. This new operation allows the device to be resumed without going through a full reset. This is particularly useful when trying to perform offline migration of a virtual machine (also known as snapshot/restore) as it allows the VMM to resume the virtual machine back to a running state after the snapshot is performed. Acked-by: Jason Wang Signed-off-by: Sebastien Boeuf Message-Id: <73b75fb87d25cff59768b4955a81fe7ffe5b4770.1672742878.git.sebastien.boeuf@intel.com> Signed-off-by: Michael S. Tsirkin Reviewed-by: Stefano Garzarella

vhost-vdpa: uAPI to suspend the device

2022-08-11T08:31:15+00:00

The ioctl adds support for suspending the device from userspace. This is a must before getting virtqueue indexes (base) for live migration, since the device could modify them after userland gets them. There are individual ways to perform that action for some devices (VHOST_NET_SET_BACKEND, VHOST_VSOCK_SET_RUNNING, ...) but there was no way to perform it for any vhost device (and, in particular, vhost-vdpa). After a successful return of the ioctl call the device must not process more virtqueue descriptors. The device can answer to read or writes of config fields as if it were not suspended. In particular, writing to "queue_enable" with a value of 1 will not make the device start processing buffers of the virtqueue. Signed-off-by: Eugenio Pérez Message-Id: <20220810171512.2343333-4-eperezma@redhat.com> Signed-off-by: Michael S. Tsirkin

vhost-vdpa: introduce uAPI to set group ASID

2022-05-31T16:44:31+00:00

Follows the vDPA support for associating ASID to a specific virtqueue group. This patch adds a uAPI to support setting them from userspace. Signed-off-by: Jason Wang Signed-off-by: Gautam Dawar Message-Id: <20220330180436.24644-15-gdawar@xilinx.com> Signed-off-by: Michael S. Tsirkin

vhost-vdpa: uAPI to get virtqueue group id

2022-05-31T16:44:31+00:00

Follows the support for virtqueue group in vDPA. This patches introduces uAPI to get the virtqueue group ID for a specific virtqueue in vhost-vdpa. Signed-off-by: Jason Wang Signed-off-by: Gautam Dawar Message-Id: <20220330180436.24644-14-gdawar@xilinx.com> Signed-off-by: Michael S. Tsirkin

vhost-vdpa: introduce uAPI to get the number of address spaces

2022-05-31T16:44:30+00:00

This patch introduces the uAPI for getting the number of address spaces supported by this vDPA device. Signed-off-by: Jason Wang Signed-off-by: Gautam Dawar Message-Id: <20220330180436.24644-13-gdawar@xilinx.com> Signed-off-by: Michael S. Tsirkin

vhost-vdpa: introduce uAPI to get the number of virtqueue groups

2022-05-31T16:44:30+00:00

Follows the vDPA support for multiple address spaces, this patch introduce uAPI for the userspace to know the number of virtqueue groups supported by the vDPA device. Signed-off-by: Jason Wang Signed-off-by: Gautam Dawar Message-Id: <20220330180436.24644-12-gdawar@xilinx.com> Signed-off-by: Michael S. Tsirkin

vhost: move the backend feature bits to vhost_types.h

2022-05-31T16:44:25+00:00

We should store feature bits in vhost_types.h as what has been done for e.g VHOST_F_LOG_ALL. Signed-off-by: Jason Wang Signed-off-by: Gautam Dawar Message-Id: <20220330180436.24644-2-gdawar@xilinx.com> Signed-off-by: Michael S. Tsirkin

vdpa: support exposing the count of vqs to userspace

2022-03-28T20:53:00+00:00

- GET_VQS_COUNT: the count of virtqueues that exposed Signed-off-by: Longpeng Link: https://lore.kernel.org/r/20220315032553.455-4-longpeng2@huawei.com Signed-off-by: Michael S. Tsirkin Acked-by: Jason Wang Signed-off-by: Longpeng <longpeng2@huawei.com>
Reviewed-by: Stefano Garzarella