user/sven/linux.git/drivers/vhost, branch v6.16.1

vhost: Reintroduce kthread API and add mode selection

2025-08-15T14:39:15Z

[ Upstream commit 7d9896e9f6d02d8aa85e63f736871f96c59a5263 ] Since commit 6e890c5d5021 ("vhost: use vhost_tasks for worker threads"), the vhost uses vhost_task and operates as a child of the owner thread. This is required for correct CPU usage accounting, especially when using containers. However, this change has caused confusion for some legacy userspace applications, and we didn't notice until it's too late. Unfortunately, it's too late to revert - we now have userspace depending both on old and new behaviour :( To address the issue, reintroduce kthread mode for vhost workers and provide a configuration to select between kthread and task worker. - Add 'fork_owner' parameter to vhost_dev to let users select kthread or task mode. Default mode is task mode(VHOST_FORK_OWNER_TASK). - Reintroduce kthread mode support: * Bring back the original vhost_worker() implementation, and renamed to vhost_run_work_kthread_list(). * Add cgroup support for the kthread * Introduce struct vhost_worker_ops: - Encapsulates create / stop / wake‑up callbacks. - vhost_worker_create() selects the proper ops according to inherit_owner. - Userspace configuration interface: * New IOCTLs: - VHOST_SET_FORK_FROM_OWNER lets userspace select task mode (VHOST_FORK_OWNER_TASK) or kthread mode (VHOST_FORK_OWNER_KTHREAD) - VHOST_GET_FORK_FROM_OWNER reads the current worker mode * Expose module parameter 'fork_from_owner_default' to allow system administrators to configure the default mode for vhost workers * Kconfig option CONFIG_VHOST_ENABLE_FORK_OWNER_CONTROL controls whether these IOCTLs and the parameter are available - The VHOST_NEW_WORKER functionality requires fork_owner to be set to true, with validation added to ensure proper configuration This partially reverts or improves upon: commit 6e890c5d5021 ("vhost: use vhost_tasks for worker threads") commit 1cdaafa1b8b4 ("vhost: replace single worker pointer with xarray") Fixes: 6e890c5d5021 ("vhost: use vhost_tasks for worker threads"), Signed-off-by: Cindy Lu Message-Id: <20250714071333.59794-2-lulu@redhat.com> Signed-off-by: Michael S. Tsirkin Acked-by: Jason Wang Tested-by: Lei Yang Signed-off-by: Sasha Levin

vhost-scsi: Fix check for inline_sg_cnt exceeding preallocated limit

2025-08-15T14:39:14Z

[ Upstream commit 400cad513c78f9af72c5a20f3611c1f1dc71d465 ] The condition comparing ret to VHOST_SCSI_PREALLOC_SGLS was incorrect, as ret holds the result of kstrtouint() (typically 0 on success), not the parsed value. Update the check to use cnt, which contains the actual user-provided value. prevents silently accepting values exceeding the maximum inline_sg_cnt. Fixes: bca939d5bcd0 ("vhost-scsi: Dynamically allocate scatterlists") Signed-off-by: Alok Tiwari Reviewed-by: Mike Christie Reviewed-by: Stefan Hajnoczi Message-Id: <20250628183405.3979538-1-alok.a.tiwari@oracle.com> Signed-off-by: Michael S. Tsirkin Acked-by: Jason Wang Signed-off-by: Sasha Levin

vhost-scsi: Fix log flooding with target does not exist errors

2025-08-15T14:39:14Z

[ Upstream commit 69cd720a8a5e9ef0f05ce5dd8c9ea6e018245c82 ] As part of the normal initiator side scanning the guest's scsi layer will loop over all possible targets and send an inquiry. Since the max number of targets for virtio-scsi is 256, this can result in 255 error messages about targets not existing if you only have a single target. When there's more than 1 vhost-scsi device each with a single target, then you get N * 255 log messages. It looks like the log message was added by accident in: commit 3f8ca2e115e5 ("vhost/scsi: Extract common handling code from control queue handler") when we added common helpers. Then in: commit 09d7583294aa ("vhost/scsi: Use common handling code in request queue handler") we converted the scsi command processing path to use the new helpers so we started to see the extra log messages during scanning. The patches were just making some code common but added the vq_err call and I'm guessing the patch author forgot to enable the vq_err call (vq_err is implemented by pr_debug which defaults to off). So this patch removes the call since it's expected to hit this path during device discovery. Fixes: 09d7583294aa ("vhost/scsi: Use common handling code in request queue handler") Signed-off-by: Mike Christie Reviewed-by: Stefan Hajnoczi Reviewed-by: Stefano Garzarella Message-Id: <20250611210113.10912-1-michael.christie@oracle.com> Signed-off-by: Michael S. Tsirkin Signed-off-by: Sasha Levin

Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

2025-05-29T15:15:35Z

Pull virtio updates from Michael Tsirkin: - A new virtio RTC driver - vhost scsi now logs write descriptors so migration works - Some hardening work in virtio core - An old spec compliance issue fixed in vhost net - A couple of cleanups, fixes in vringh, virtio-pci, vdpa * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: virtio: reject shm region if length is zero virtio_rtc: Add RTC class driver virtio_rtc: Add Arm Generic Timer cross-timestamping virtio_rtc: Add PTP clocks virtio_rtc: Add module and driver core vringh: use bvec_kmap_local vhost: vringh: Use matching allocation type in resize_iovec() virtio-pci: Fix result size returned for the admin command completion vdpa/octeon_ep: Control PCI dev enabling manually vhost-scsi: log event queue write descriptors vhost-scsi: log control queue write descriptors vhost-scsi: log I/O queue write descriptors vhost-scsi: adjust vhost_scsi_get_desc() to log vring descriptors vhost: modify vhost_log_write() for broader users

vringh: use bvec_kmap_local

2025-05-27T14:27:53Z

Use the bvec_kmap_local helper rather than digging into the bvec internals. Signed-off-by: Christoph Hellwig Message-Id: <20250501142244.2888227-1-hch@lst.de> Signed-off-by: Michael S. Tsirkin Reviewed-by: Chaitanya Kulkarni

vhost: vringh: Use matching allocation type in resize_iovec()

2025-05-27T14:27:53Z

In preparation for making the kmalloc family of allocators type aware, we need to make sure that the returned type from the allocation matches the type of the variable being assigned. (Before, the allocator would always return "void *", which can be implicitly cast to any pointer type.) The assigned type is "struct kvec *", but the returned type will be "struct iovec *". These have the same allocation size, so there is no bug: struct kvec { void *iov_base; /* and that should *never* hold a userland pointer */ size_t iov_len; }; struct iovec { void __user *iov_base; /* BSD uses caddr_t (1003.1g requires void *) */ __kernel_size_t iov_len; /* Must be size_t (1003.1g) */ }; Adjust the allocation type to match the assignment. Signed-off-by: Kees Cook Message-Id: <20250426062214.work.334-kees@kernel.org> Signed-off-by: Michael S. Tsirkin

vhost-scsi: log event queue write descriptors

2025-05-18T21:25:24Z

Log write descriptors for the event queue, leveraging vhost_get_vq_desc() to retrieve the array of write descriptors to obtain the log buffer. There is only one path for event queue. Suggested-by: Joao Martins Signed-off-by: Dongli Zhang Reviewed-by: Mike Christie Message-Id: <20250403063028.16045-9-dongli.zhang@oracle.com> Signed-off-by: Michael S. Tsirkin

vhost-scsi: log control queue write descriptors

2025-05-18T21:25:24Z

Log write descriptors for the control queue, leveraging vhost_scsi_get_desc() and vhost_get_vq_desc() to retrieve the array of write descriptors to obtain the log buffer. For Task Management Requests, similar to the I/O queue, store the log buffer during the submission path and log it in the completion or error handling path. For Asynchronous Notifications, only the submission path is involved. Suggested-by: Joao Martins Signed-off-by: Dongli Zhang Message-Id: <20250403063028.16045-8-dongli.zhang@oracle.com> Signed-off-by: Michael S. Tsirkin Reviewed-by: Mike Christie

vhost-scsi: log I/O queue write descriptors

2025-05-18T21:25:24Z

Log write descriptors for the I/O queue, leveraging vhost_scsi_get_desc() and vhost_get_vq_desc() to retrieve the array of write descriptors to obtain the log buffer. In addition, introduce a vhost-scsi specific function to log vring descriptors. In this function, the 'partial' argument is set to false, and the 'len' argument is set to 0, because vhost-scsi always logs all pages shared by a vring descriptor. Add WARN_ON_ONCE() since vhost-scsi doesn't support VIRTIO_F_ACCESS_PLATFORM. The per-cmd log buffer is allocated on demand in the submission path after VHOST_F_LOG_ALL is set. Return -ENOMEM on allocation failure, in order to send SAM_STAT_TASK_SET_FULL to the guest. It isn't reclaimed in the completion path. Instead, it is reclaimed when VHOST_F_LOG_ALL is removed, or during VHOST_SCSI_SET_ENDPOINT when all commands are destroyed. Store the log buffer during the submission path and log it in the completion path. Logging is also required in the error handling path of the submission process. Suggested-by: Joao Martins Signed-off-by: Dongli Zhang Message-Id: <20250403063028.16045-7-dongli.zhang@oracle.com> Signed-off-by: Michael S. Tsirkin Reviewed-by: Mike Christie

vhost-scsi: adjust vhost_scsi_get_desc() to log vring descriptors

2025-05-18T21:25:24Z

Adjust vhost_scsi_get_desc() to facilitate logging of vring descriptors. Add new arguments to allow passing the log buffer and length to vhost_get_vq_desc(). In addition, reset 'log_num' since vhost_get_vq_desc() may reset it only after certain condition checks. Suggested-by: Joao Martins Signed-off-by: Dongli Zhang Reviewed-by: Mike Christie Message-Id: <20250403063028.16045-6-dongli.zhang@oracle.com> Signed-off-by: Michael S. Tsirkin