kernel/linux.git/drivers/vfio, branch v6.1

vfio/pci: Check the device set open count on reset

2022-11-10T19:03:36+00:00

vfio_pci_dev_set_needs_reset() inspects the open_count of every device in the set to determine whether a reset is allowed. The current device always has open_count == 1 within vfio_pci_core_disable(), effectively disabling the reset logic. This field is also documented as private in vfio_device, so it should not be used to determine whether other devices in the set are open. Checking for vfio_device_set_open_count() > 1 on the device set fixes both issues. After commit 2cd8b14aaa66 ("vfio/pci: Move to the device set infrastructure"), failure to create a new file for a device would cause the reset to be skipped due to open_count being decremented after calling close_device() in the error path. After commit eadd86f835c6 ("vfio: Remove calls to vfio_group_add_container_user()"), releasing a device would always skip the reset due to an ordering change in vfio_device_fops_release(). Failing to reset the device leaves it in an unknown state, potentially causing errors when it is accessed later or bound to a different driver. This issue was observed with a Radeon RX Vega 56 [1002:687f] (rev c3) assigned to a Windows guest. After shutting down the guest, unbinding the device from vfio-pci, and binding the device to amdgpu: [ 548.007102] [drm:psp_hw_start [amdgpu]] *ERROR* PSP create ring failed! [ 548.027174] [drm:psp_hw_init [amdgpu]] *ERROR* PSP firmware loading failed [ 548.027242] [drm:amdgpu_device_fw_loading [amdgpu]] *ERROR* hw_init of IP block failed -22 [ 548.027306] amdgpu 0000:0a:00.0: amdgpu: amdgpu_device_ip_init failed [ 548.027308] amdgpu 0000:0a:00.0: amdgpu: Fatal error during GPU init Fixes: 2cd8b14aaa66 ("vfio/pci: Move to the device set infrastructure") Fixes: eadd86f835c6 ("vfio: Remove calls to vfio_group_add_container_user()") Signed-off-by: Anthony DeRossi Reviewed-by: Jason Gunthorpe Reviewed-by: Kevin Tian Link: https://lore.kernel.org/r/20221110014027.28780-4-ajderossi@gmail.com Signed-off-by: Alex Williamson

vfio: Export the device set open count

2022-11-10T19:03:36+00:00

The open count of a device set is the sum of the open counts of all devices in the set. Drivers can use this value to determine whether shared resources are in use without tracking them manually or accessing the private open_count in vfio_device. Signed-off-by: Anthony DeRossi Reviewed-by: Jason Gunthorpe Reviewed-by: Kevin Tian Reviewed-by: Yi Liu Link: https://lore.kernel.org/r/20221110014027.28780-3-ajderossi@gmail.com Signed-off-by: Alex Williamson

vfio: Fix container device registration life cycle

2022-11-10T19:03:36+00:00

In vfio_device_open(), vfio_device_container_register() is always called when open_count == 1. On error, vfio_device_container_unregister() is only called when open_count == 1 and close_device is set. This leaks a registration for devices without a close_device implementation. In vfio_device_fops_release(), vfio_device_container_unregister() is called unconditionally. This can cause a device to be unregistered multiple times. Treating container device registration/unregistration uniformly (always when open_count == 1) fixes both issues. Fixes: ce4b4657ff18 ("vfio: Replace the DMA unmapping notifier with a callback") Signed-off-by: Anthony DeRossi Reviewed-by: Jason Gunthorpe Reviewed-by: Kevin Tian Reviewed-by: Yi Liu Link: https://lore.kernel.org/r/20221110014027.28780-2-ajderossi@gmail.com Signed-off-by: Alex Williamson

Merge tag 'vfio-v6.1-rc1' of https://github.com/awilliam/linux-vfio

2022-10-12T21:46:48+00:00

Pull VFIO updates from Alex Williamson: - Prune private items from vfio_pci_core.h to a new internal header, fix missed function rename, and refactor vfio-pci interrupt defines (Jason Gunthorpe) - Create consistent naming and handling of ioctls with a function per ioctl for vfio-pci and vfio group handling, use proper type args where available (Jason Gunthorpe) - Implement a set of low power device feature ioctls allowing userspace to make use of power states such as D3cold where supported (Abhishek Sahu) - Remove device counter on vfio groups, which had restricted the page pinning interface to singleton groups to account for limitations in the type1 IOMMU backend. Document usage as limited to emulated IOMMU devices, ie. traditional mdev devices where this restriction is consistent (Jason Gunthorpe) - Correct function prefix in hisi_acc driver incurred during previous refactoring (Shameer Kolothum) - Correct typo and remove redundant warning triggers in vfio-fsl driver (Christophe JAILLET) - Introduce device level DMA dirty tracking uAPI and implementation in the mlx5 variant driver (Yishai Hadas & Joao Martins) - Move much of the vfio_device life cycle management into vfio core, simplifying and avoiding duplication across drivers. This also facilitates adding a struct device to vfio_device which begins the introduction of device rather than group level user support and fills a gap allowing userspace identify devices as vfio capable without implicit knowledge of the driver (Kevin Tian & Yi Liu) - Split vfio container handling to a separate file, creating a more well defined API between the core and container code, masking IOMMU backend implementation from the core, allowing for an easier future transition to an iommufd based implementation of the same (Jason Gunthorpe) - Attempt to resolve race accessing the iommu_group for a device between vfio releasing DMA ownership and removal of the device from the IOMMU driver. Follow-up with support to allow vfio_group to exist with NULL iommu_group pointer to support existing userspace use cases of holding the group file open (Jason Gunthorpe) - Fix error code and hi/lo register manipulation issues in the hisi_acc variant driver, along with various code cleanups (Longfang Liu) - Fix a prior regression in GVT-g group teardown, resulting in unreleased resources (Jason Gunthorpe) - A significant cleanup and simplification of the mdev interface, consolidating much of the open coded per driver sysfs interface support into the mdev core (Christoph Hellwig) - Simplification of tracking and locking around vfio_groups that fall out from previous refactoring (Jason Gunthorpe) - Replace trivial open coded f_ops tests with new helper (Alex Williamson) * tag 'vfio-v6.1-rc1' of https://github.com/awilliam/linux-vfio: (77 commits) vfio: More vfio_file_is_group() use cases vfio: Make the group FD disassociate from the iommu_group vfio: Hold a reference to the iommu_group in kvm for SPAPR vfio: Add vfio_file_is_group() vfio: Change vfio_group->group_rwsem to a mutex vfio: Remove the vfio_group->users and users_comp vfio/mdev: add mdev available instance checking to the core vfio/mdev: consolidate all the description sysfs into the core code vfio/mdev: consolidate all the available_instance sysfs into the core code vfio/mdev: consolidate all the name sysfs into the core code vfio/mdev: consolidate all the device_api sysfs into the core code vfio/mdev: remove mtype_get_parent_dev vfio/mdev: remove mdev_parent_dev vfio/mdev: unexport mdev_bus_type vfio/mdev: remove mdev_from_dev vfio/mdev: simplify mdev_type handling vfio/mdev: embedd struct mdev_parent in the parent data structure vfio/mdev: make mdev.h standalone includable drm/i915/gvt: simplify vgpu configuration management drm/i915/gvt: fix a memory leak in intel_gvt_init_vgpu_types ...

vfio: More vfio_file_is_group() use cases

2022-10-07T19:06:52+00:00

Replace further open coded tests with helper. Reviewed-by: Jason Gunthorpe Link: https://lore.kernel.org/r/166516896843.1215571.5378890510536477434.stgit@omen Signed-off-by: Alex Williamson

vfio: Make the group FD disassociate from the iommu_group

2022-10-07T14:10:52+00:00

Allow the vfio_group struct to exist with a NULL iommu_group pointer. When the pointer is NULL the vfio_group users promise not to touch the iommu_group. This allows a driver to be hot unplugged while userspace is keeping the group FD open. Remove all the code waiting for the group FD to close. This fixes a userspace regression where we learned that virtnodedevd leaves a group FD open even though the /dev/ node for it has been deleted and all the drivers for it unplugged. Fixes: ca5f21b25749 ("vfio: Follow a strict lifetime for struct iommu_group") Reported-by: Christian Borntraeger Tested-by: Matthew Rosato Tested-by: Christian Borntraeger Tested-by: Eric Farman Signed-off-by: Jason Gunthorpe Link: https://lore.kernel.org/r/3-v2-15417f29324e+1c-vfio_group_disassociate_jgg@nvidia.com Signed-off-by: Alex Williamson

vfio: Hold a reference to the iommu_group in kvm for SPAPR

2022-10-07T14:10:52+00:00

SPAPR exists completely outside the normal iommu driver framework, the groups it creates are fake and are only created to enable VFIO's uAPI. Thus, it does not need to follow the iommu core rule that the iommu_group will only be touched while a driver is attached. Carry a group reference into KVM and have KVM directly manage the lifetime of this object independently of VFIO. This means KVM no longer relies on the vfio group file being valid to maintain the group reference. Tested-by: Matthew Rosato Signed-off-by: Jason Gunthorpe Link: https://lore.kernel.org/r/2-v2-15417f29324e+1c-vfio_group_disassociate_jgg@nvidia.com Signed-off-by: Alex Williamson

vfio: Add vfio_file_is_group()

2022-10-07T14:10:52+00:00

This replaces uses of vfio_file_iommu_group() which were only detecting if the file is a VFIO file with no interest in the actual group. The only remaning user of vfio_file_iommu_group() is in KVM for the SPAPR stuff. It passes the iommu_group into the arch code through kvm for some reason. Tested-by: Matthew Rosato Tested-by: Christian Borntraeger Tested-by: Eric Farman Signed-off-by: Jason Gunthorpe Link: https://lore.kernel.org/r/1-v2-15417f29324e+1c-vfio_group_disassociate_jgg@nvidia.com Signed-off-by: Alex Williamson

vfio: Change vfio_group->group_rwsem to a mutex

2022-10-04T18:06:58+00:00

These days not much is using the read side: - device first open - ioctl_get_status - device FD release - check enforced_coherent None of this is performance, so just make it into a normal mutex. Signed-off-by: Jason Gunthorpe Reviewed-by: Kevin Tian Link: https://lore.kernel.org/r/2-v1-917e3647f123+b1a-vfio_group_users_jgg@nvidia.com Signed-off-by: Alex Williamson

vfio: Remove the vfio_group->users and users_comp

2022-10-04T18:06:58+00:00

Kevin points out that the users is really just tracking if group->opened_file is set, so we can simplify this code to a wait_queue that looks for !opened_file under the group_rwsem. Signed-off-by: Jason Gunthorpe Reviewed-by: Kevin Tian Link: https://lore.kernel.org/r/1-v1-917e3647f123+b1a-vfio_group_users_jgg@nvidia.com Signed-off-by: Alex Williamson