linux-stable.git/drivers/vfio, branch v6.1.2 Linux kernel stable tree vfio/iova_bitmap: refactor iova_bitmap_set() to better handle page boundaries 2022-12-31T12:32:41+00:00 Joao Martins joao.m.martins@oracle.com 2022-11-29T13:12:35+00:00 ba090c6debb5de85ef1289ce23e9adda05e59f3f [ Upstream commit b058ea3ab5afea873ab8d976277539ca9e43869a ] Commit f38044e5ef58 ("vfio/iova_bitmap: Fix PAGE_SIZE unaligned bitmaps") had fixed the unaligned bitmaps by capping the remaining iterable set at the start of the bitmap. Although, that mistakenly worked around iova_bitmap_set() incorrectly setting bits across page boundary. Fix this by reworking the loop inside iova_bitmap_set() to iterate over a range of bits to set (cur_bit .. last_bit) which may span different pinned pages, thus updating @page_idx and @offset as it sets the bits. The previous cap to the first page is now adjusted to be always accounted rather than when there's only a non-zero pgoff. While at it, make @page_idx , @offset and @nbits to be unsigned int given that it won't be more than 512 and 4096 respectively (even a bigger PAGE_SIZE or a smaller struct page size won't make this bigger than the above 32-bit max). Also, delete the stale kdoc on Return type. Cc: Avihai Horon <avihaih@nvidia.com> Fixes: f38044e5ef58 ("vfio/iova_bitmap: Fix PAGE_SIZE unaligned bitmaps") Co-developed-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Avihai Horon <avihaih@nvidia.com> Link: https://lore.kernel.org/r/20221129131235.38880-1-joao.m.martins@oracle.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit b058ea3ab5afea873ab8d976277539ca9e43869a ]

Commit f38044e5ef58 ("vfio/iova_bitmap: Fix PAGE_SIZE unaligned bitmaps")
had fixed the unaligned bitmaps by capping the remaining iterable set at
the start of the bitmap. Although, that mistakenly worked around
iova_bitmap_set() incorrectly setting bits across page boundary.

Fix this by reworking the loop inside iova_bitmap_set() to iterate over a
range of bits to set (cur_bit .. last_bit) which may span different pinned
pages, thus updating @page_idx and @offset as it sets the bits. The
previous cap to the first page is now adjusted to be always accounted
rather than when there's only a non-zero pgoff.

While at it, make @page_idx , @offset and @nbits to be unsigned int given
that it won't be more than 512 and 4096 respectively (even a bigger
PAGE_SIZE or a smaller struct page size won't make this bigger than the
above 32-bit max). Also, delete the stale kdoc on Return type.

Cc: Avihai Horon <avihaih@nvidia.com>
Fixes: f38044e5ef58 ("vfio/iova_bitmap: Fix PAGE_SIZE unaligned bitmaps")
Co-developed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Avihai Horon <avihaih@nvidia.com>
Link: https://lore.kernel.org/r/20221129131235.38880-1-joao.m.martins@oracle.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
vfio/iova_bitmap: Fix PAGE_SIZE unaligned bitmaps 2022-12-31T12:32:38+00:00 Joao Martins joao.m.martins@oracle.com 2022-10-25T19:31:14+00:00 31ef3d554d592c7212d7d0d4320a1a5bdf2ebe26 [ Upstream commit f38044e5ef58ad0346fdabd7027ea5c1e1a3b624 ] iova_bitmap_set() doesn't consider the end of the page boundary when the first bitmap page offset isn't zero, and wrongly changes the consecutive page right after. Consequently this leads to missing dirty pages from reported by the device as seen from the VMM. The current logic iterates over a given number of base pages and clamps it to the remaining indexes to iterate in the last page. Instead of having to consider extra pages to pin (e.g. first and extra pages), just handle the first page as its own range and let the rest of the bitmap be handled as if it was base page aligned. This is done by changing iova_bitmap_mapped_remaining() to return PAGE_SIZE - pgoff (on the first bitmap page), and leads to pgoff being set to 0 on following iterations. Fixes: 58ccf0190d19 ("vfio: Add an IOVA bitmap support") Reported-by: Avihai Horon <avihaih@nvidia.com> Tested-by: Avihai Horon <avihaih@nvidia.com> Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Link: https://lore.kernel.org/r/20221025193114.58695-3-joao.m.martins@oracle.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit f38044e5ef58ad0346fdabd7027ea5c1e1a3b624 ]

iova_bitmap_set() doesn't consider the end of the page boundary when the
first bitmap page offset isn't zero, and wrongly changes the consecutive
page right after. Consequently this leads to missing dirty pages from
reported by the device as seen from the VMM.

The current logic iterates over a given number of base pages and clamps it
to the remaining indexes to iterate in the last page.  Instead of having to
consider extra pages to pin (e.g. first and extra pages), just handle the
first page as its own range and let the rest of the bitmap be handled as if
it was base page aligned.

This is done by changing iova_bitmap_mapped_remaining() to return PAGE_SIZE
- pgoff (on the first bitmap page), and leads to pgoff being set to 0 on
following iterations.

Fixes: 58ccf0190d19 ("vfio: Add an IOVA bitmap support")
Reported-by: Avihai Horon <avihaih@nvidia.com>
Tested-by: Avihai Horon <avihaih@nvidia.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Link: https://lore.kernel.org/r/20221025193114.58695-3-joao.m.martins@oracle.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
vfio: platform: Do not pass return buffer to ACPI _RST method 2022-12-31T12:32:38+00:00 Rafael Mendonca rafaelmendsr@gmail.com 2022-10-18T15:28:25+00:00 f0865e4f2c820e24334171bdfaeaf29ce79125ee [ Upstream commit e67e070632a665c932d534b8b800477bb3111449 ] The ACPI _RST method has no return value, there's no need to pass a return buffer to acpi_evaluate_object(). Fixes: d30daa33ec1d ("vfio: platform: call _RST method when using ACPI") Signed-off-by: Rafael Mendonca <rafaelmendsr@gmail.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Link: https://lore.kernel.org/r/20221018152825.891032-1-rafaelmendsr@gmail.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit e67e070632a665c932d534b8b800477bb3111449 ]

The ACPI _RST method has no return value, there's no need to pass a return
buffer to acpi_evaluate_object().

Fixes: d30daa33ec1d ("vfio: platform: call _RST method when using ACPI")
Signed-off-by: Rafael Mendonca <rafaelmendsr@gmail.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Link: https://lore.kernel.org/r/20221018152825.891032-1-rafaelmendsr@gmail.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
vfio/pci: Check the device set open count on reset 2022-11-10T19:03:36+00:00 Anthony DeRossi ajderossi@gmail.com 2022-11-10T01:40:27+00:00 e806e223621e4f5105170df69d7311dc3fb4bbb4 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 <psp> 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 <ajderossi@gmail.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Link: https://lore.kernel.org/r/20221110014027.28780-4-ajderossi@gmail.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com> 
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 <psp> 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 <ajderossi@gmail.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20221110014027.28780-4-ajderossi@gmail.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
vfio: Export the device set open count 2022-11-10T19:03:36+00:00 Anthony DeRossi ajderossi@gmail.com 2022-11-10T01:40:26+00:00 5cd189e410debedda416fecfc12f4716b5829845 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 <ajderossi@gmail.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Reviewed-by: Yi Liu <yi.l.liu@intel.com> Link: https://lore.kernel.org/r/20221110014027.28780-3-ajderossi@gmail.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com> 
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 <ajderossi@gmail.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
Link: https://lore.kernel.org/r/20221110014027.28780-3-ajderossi@gmail.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
vfio: Fix container device registration life cycle 2022-11-10T19:03:36+00:00 Anthony DeRossi ajderossi@gmail.com 2022-11-10T01:40:25+00:00 7fdba0011157861892c470995ff586a1871e603f 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 <ajderossi@gmail.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Reviewed-by: Yi Liu <yi.l.liu@intel.com> Link: https://lore.kernel.org/r/20221110014027.28780-2-ajderossi@gmail.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com> 
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 <ajderossi@gmail.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
Link: https://lore.kernel.org/r/20221110014027.28780-2-ajderossi@gmail.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Merge tag 'vfio-v6.1-rc1' of https://github.com/awilliam/linux-vfio 2022-10-12T21:46:48+00:00 Linus Torvalds torvalds@linux-foundation.org 2022-10-12T21:46:48+00:00 d3cf40513330752238ae585fdb0e46ec6baa588b 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 ... 
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 Alex Williamson alex.williamson@redhat.com 2022-10-07T18:03:00+00:00 b1b8132a651cf6a5b18a01d8f1bd304f5d210315 Replace further open coded tests with helper. Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/166516896843.1215571.5378890510536477434.stgit@omen Signed-off-by: Alex Williamson <alex.williamson@redhat.com> 
Replace further open coded tests with helper.

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/166516896843.1215571.5378890510536477434.stgit@omen
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
vfio: Make the group FD disassociate from the iommu_group 2022-10-07T14:10:52+00:00 Jason Gunthorpe jgg@nvidia.com 2022-10-07T14:04:41+00:00 3dd59a7dcb97e6e40d6385a1a3faa9392b6d184a 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 <borntraeger@linux.ibm.com> Tested-by: Matthew Rosato <mjrosato@linux.ibm.com> Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> Tested-by: Eric Farman <farman@linux.ibm.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/3-v2-15417f29324e+1c-vfio_group_disassociate_jgg@nvidia.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com> 
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 <borntraeger@linux.ibm.com>
Tested-by: Matthew Rosato <mjrosato@linux.ibm.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Tested-by: Eric Farman <farman@linux.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/3-v2-15417f29324e+1c-vfio_group_disassociate_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
vfio: Hold a reference to the iommu_group in kvm for SPAPR 2022-10-07T14:10:52+00:00 Jason Gunthorpe jgg@nvidia.com 2022-10-07T14:04:40+00:00 819da99a7360f7e197038d12f0eba626bde11856 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 <mjrosato@linux.ibm.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/2-v2-15417f29324e+1c-vfio_group_disassociate_jgg@nvidia.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com> 
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 <mjrosato@linux.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/2-v2-15417f29324e+1c-vfio_group_disassociate_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>