kernel/linux.git/samples/vfio-mdev/mtty.c, branch linux-7.1.y

vfio: Adapt drivers to use the core helper vfio_check_precopy_ioctl

2026-03-19T18:32:09+00:00

Introduce a core helper function for VFIO_MIG_GET_PRECOPY_INFO and adapt all drivers to use it. It centralizes the common code and ensures that output flags are cleared on entry, in case user opts in to VFIO_DEVICE_FEATURE_MIG_PRECOPY_INFOv2. This preventing any unintended echoing of userspace data back to userspace. Signed-off-by: Yishai Hadas Link: https://lore.kernel.org/r/20260317161753.18964-4-yishaih@nvidia.com Signed-off-by: Alex Williamson

vfio: mdev: replace mtty_dev->vd_class with a const struct class

2026-03-19T18:32:07+00:00

The class_create() call has been deprecated in favor of class_register() as the driver core now allows for a struct class to be in read-only memory. Replace mtty_dev->vd_class with a const struct class and drop the class_create() call. Compile tested and found no errors/warns in dmesg after enabling CONFIG_VFIO and CONFIG_SAMPLE_VFIO_MDEV_MTTY. Link: https://lore.kernel.org/all/2023040244-duffel-pushpin-f738@gregkh/ Suggested-by: Greg Kroah-Hartman Signed-off-by: Jori Koolstra Acked-by: Greg Kroah-Hartman Link: https://lore.kernel.org/r/20260308214939.1215682-1-jkoolstra@xs4all.nl Signed-off-by: Alex Williamson

vfio: Move the remaining drivers to get_region_info_caps

2025-11-12T22:06:41+00:00

Remove the duplicate code and change info to a pointer. caps are not used. Reviewed-by: Kevin Tian Acked-by: Pranjal Shrivastava Signed-off-by: Jason Gunthorpe Link: https://lore.kernel.org/r/21-v2-2a9e24d62f1b+e10a-vfio_get_region_info_op_jgg@nvidia.com Signed-off-by: Alex Williamson

vfio/mtty: Provide a get_region_info op

2025-11-12T22:05:02+00:00

Move it out of mtty_ioctl() and re-indent it. Reviewed-by: Kevin Tian Acked-by: Pranjal Shrivastava Signed-off-by: Jason Gunthorpe Link: https://lore.kernel.org/r/6-v2-2a9e24d62f1b+e10a-vfio_get_region_info_op_jgg@nvidia.com Signed-off-by: Alex Williamson

vfio/mtty: Fix spelling typo in samples/vfio-mdev

2025-11-05T19:10:34+00:00

The comment incorrectly used "atleast" instead of "at least". Signed-off-by: Chu Guangqing Link: https://lore.kernel.org/r/20251015015954.2363-2-chuguangqing@inspur.com Signed-off-by: Alex Williamson

[tree-wide] finally take no_llseek out

2024-09-27T15:18:43+00:00

no_llseek had been defined to NULL two years ago, in commit 868941b14441 ("fs: remove no_llseek") To quote that commit, At -rc1 we'll need do a mechanical removal of no_llseek - git grep -l -w no_llseek | grep -v porting.rst | while read i; do sed -i '/\/d' $i done would do it. Unfortunately, that hadn't been done. Linus, could you do that now, so that we could finally put that thing to rest? All instances are of the form .llseek = no_llseek, so it's obviously safe. Signed-off-by: Al Viro Signed-off-by: Linus Torvalds

vfio-mdev: add missing MODULE_DESCRIPTION() macros

2024-07-17T18:24:13+00:00

Since commit 1fffe7a34c89 ("script: modpost: emit a warning when the description is missing"), a module without a MODULE_DESCRIPTION() will result in a warning with make W=1. The following warnings are being observed in samples/vfio-mdev: WARNING: modpost: missing MODULE_DESCRIPTION() in samples/vfio-mdev/mtty.o WARNING: modpost: missing MODULE_DESCRIPTION() in samples/vfio-mdev/mdpy.o WARNING: modpost: missing MODULE_DESCRIPTION() in samples/vfio-mdev/mdpy-fb.o WARNING: modpost: missing MODULE_DESCRIPTION() in samples/vfio-mdev/mbochs.o Add the missing invocations of the MODULE_DESCRIPTION() macro to these modules. And in the case of mtty.c, remove the now redundant instance of the MODULE_INFO() macro. Signed-off-by: Jeff Johnson Link: https://lore.kernel.org/r/20240715-md-vfio-mdev-v2-1-59a4c5e924bc@quicinc.com Signed-off-by: Alex Williamson

eventfd: simplify eventfd_signal()

2023-11-28T13:08:38+00:00

Ever since the eventfd type was introduced back in 2007 in commit e1ad7468c77d ("signal/timer/event: eventfd core") the eventfd_signal() function only ever passed 1 as a value for @n. There's no point in keeping that additional argument. Link: https://lore.kernel.org/r/20231122-vfs-eventfd-signal-v2-2-bd549b14ce0c@kernel.org Acked-by: Xu Yilun Acked-by: Andrew Donnellan # ocxl Acked-by: Eric Farman # s390 Reviewed-by: Jan Kara Reviewed-by: Jens Axboe Signed-off-by: Christian Brauner

vfio/mtty: Enable migration support

2023-10-24T21:03:10+00:00

The mtty driver exposes a PCI serial device to userspace and therefore makes an easy target for a sample device supporting migration. The device does not make use of DMA, therefore we can easily claim support for the migration P2P states, as well as dirty logging. This implementation also makes use of PRE_COPY support in order to provide migration stream compatibility testing, which should generally be considered good practice. Reviewed-by: Cédric Le Goater Link: https://lore.kernel.org/r/20231016224736.2575718-3-alex.williamson@redhat.com Signed-off-by: Alex Williamson

vfio/mtty: Overhaul mtty interrupt handling

2023-10-24T21:02:55+00:00

The mtty driver does not currently conform to the vfio SET_IRQS uAPI. For example, it claims to support mask and unmask of INTx, but actually does nothing. It claims to support AUTOMASK for INTx, but doesn't. It fails to teardown eventfds under the full semantics specified by the SET_IRQS ioctl. It also fails to teardown eventfds when the device is closed, leading to memory leaks. It claims to support the request IRQ, but doesn't. Fix all these. A side effect of this is that QEMU will now report a warning: vfio : Failed to set up UNMASK eventfd signaling for interrupt \ INTX-0: VFIO_DEVICE_SET_IRQS failure: Inappropriate ioctl for device The fact is that the unmask eventfd was never supported but quietly failed. mtty never honored the AUTOMASK behavior, therefore there was nothing to unmask. QEMU is verbose about the failure, but properly falls back to userspace unmasking. Fixes: 9d1a546c53b4 ("docs: Sample driver to demonstrate how to use Mediated device framework.") Reviewed-by: Cédric Le Goater Link: https://lore.kernel.org/r/20231016224736.2575718-2-alex.williamson@redhat.com Signed-off-by: Alex Williamson