kernel/linux.git/include/uapi/linux/vfio.h, branch v6.12.80

vfio/migration: Add debugfs to live migration driver

2023-12-04T21:29:08+00:00

There are multiple devices, software and operational steps involved in the process of live migration. An error occurred on any node may cause the live migration operation to fail. This complex process makes it very difficult to locate and analyze the cause when the function fails. In order to quickly locate the cause of the problem when the live migration fails, I added a set of debugfs to the vfio live migration driver. +-------------------------------------------+ | | | | | QEMU | | | | | +---+----------------------------+----------+ | ^ | ^ | | | | | | | | v | v | +---------+--+ +---------+--+ |src vfio_dev| |dst vfio_dev| +--+---------+ +--+---------+ | ^ | ^ | | | | v | | | +-----------+----+ +-----------+----+ |src dev debugfs | |dst dev debugfs | +----------------+ +----------------+ The entire debugfs directory will be based on the definition of the CONFIG_DEBUG_FS macro. If this macro is not enabled, the interfaces in vfio.h will be empty definitions, and the creation and initialization of the debugfs directory will not be executed. vfio | +--- | +---migration | +--state | +--- +---migration +--state debugfs will create a public root directory "vfio" file. then create a dev_name() file for each live migration device. First, create a unified state acquisition file of "migration" in this device directory. Then, create a public live migration state lookup file "state". Signed-off-by: Longfang Liu Reviewed-by: Cédric Le Goater Link: https://lore.kernel.org/r/20231106072225.28577-2-liulongfang@huawei.com Signed-off-by: Alex Williamson

vfio: use __aligned_u64 in struct vfio_device_ioeventfd

2023-09-28T18:12:08+00:00

The memory layout of struct vfio_device_ioeventfd is architecture-dependent due to a u64 field and a struct size that is not a multiple of 8 bytes: - On x86_64 the struct size is padded to a multiple of 8 bytes. - On x32 the struct size is only a multiple of 4 bytes, not 8. - Other architectures may vary. Use __aligned_u64 to make memory layout consistent. This reduces the chance that 32-bit userspace on a 64-bit kernel breakage. This patch increases the struct size on x32 but this is safe because of the struct's argsz field. The kernel may grow the struct as long as it still supports smaller argsz values from userspace (e.g. applications compiled against older kernel headers). The code that uses struct vfio_device_ioeventfd already works correctly when the struct size grows, so only the struct definition needs to be changed. Suggested-by: Jason Gunthorpe Reviewed-by: Jason Gunthorpe Reviewed-by: Kevin Tian Signed-off-by: Stefan Hajnoczi Link: https://lore.kernel.org/r/20230918205617.1478722-4-stefanha@redhat.com Signed-off-by: Alex Williamson

vfio: use __aligned_u64 in struct vfio_device_gfx_plane_info

2023-09-28T18:12:08+00:00

The memory layout of struct vfio_device_gfx_plane_info is architecture-dependent due to a u64 field and a struct size that is not a multiple of 8 bytes: - On x86_64 the struct size is padded to a multiple of 8 bytes. - On x32 the struct size is only a multiple of 4 bytes, not 8. - Other architectures may vary. Use __aligned_u64 to make memory layout consistent. This reduces the chance of 32-bit userspace on a 64-bit kernel breakage. This patch increases the struct size on x32 but this is safe because of the struct's argsz field. The kernel may grow the struct as long as it still supports smaller argsz values from userspace (e.g. applications compiled against older kernel headers). Suggested-by: Jason Gunthorpe Reviewed-by: Kevin Tian Signed-off-by: Stefan Hajnoczi Link: https://lore.kernel.org/r/20230918205617.1478722-3-stefanha@redhat.com Signed-off-by: Alex Williamson

vfio: trivially use __aligned_u64 for ioctl structs

2023-09-28T18:12:08+00:00

u64 alignment behaves differently depending on the architecture and so offers __aligned_u64 to achieve consistent behavior in kernel<->userspace ABIs. There are structs in that can trivially be updated to __aligned_u64 because the struct sizes are multiples of 8 bytes. There is no change in memory layout on any CPU architecture and therefore this change is safe. The commits that follow this one handle the trickier cases where explanation about ABI breakage is necessary. Suggested-by: Jason Gunthorpe Reviewed-by: Jason Gunthorpe Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Kevin Tian Signed-off-by: Stefan Hajnoczi Link: https://lore.kernel.org/r/20230918205617.1478722-2-stefanha@redhat.com Signed-off-by: Alex Williamson

vfio: add bus master feature to device feature ioctl

2023-09-28T18:12:07+00:00

add bus mastering control to VFIO_DEVICE_FEATURE IOCTL. The VFIO user can use this feature to enable or disable the Bus Mastering of a device bound to VFIO. Co-developed-by: Shubham Rohila Signed-off-by: Shubham Rohila Signed-off-by: Nipun Gupta Link: https://lore.kernel.org/r/20230915045423.31630-2-nipun.gupta@amd.com Signed-off-by: Alex Williamson

Merge tag 'for-linus-iommufd' of git://git.kernel.org/pub/scm/linux/kernel/git/jgg/iommufd

2023-08-31T03:41:37+00:00

Pull iommufd updates from Jason Gunthorpe: "On top of the vfio updates is built some new iommufd functionality: - IOMMU_HWPT_ALLOC allows userspace to directly create the low level IO Page table objects and affiliate them with IOAS objects that hold the translation mapping. This is the basic functionality for the normal IOMMU_DOMAIN_PAGING domains. - VFIO_DEVICE_ATTACH_IOMMUFD_PT can be used to replace the current translation. This is wired up to through all the layers down to the driver so the driver has the ability to implement a hitless replacement. This is necessary to fully support guest behaviors when emulating HW (eg guest atomic change of translation) - IOMMU_GET_HW_INFO returns information about the IOMMU driver HW that owns a VFIO device. This includes support for the Intel iommu, and patches have been posted for all the other server IOMMU. Along the way are a number of internal items: - New iommufd kernel APIs: iommufd_ctx_has_group(), iommufd_device_to_ictx(), iommufd_device_to_id(), iommufd_access_detach(), iommufd_ctx_from_fd(), iommufd_device_replace() - iommufd now internally tracks iommu_groups as it needs some per-group data - Reorganize how the internal hwpt allocation flows to have more robust locking - Improve the access interfaces to support detach and replace of an IOAS from an access - New selftests and a rework of how the selftests creates a mock iommu driver to be more like a real iommu driver" Link: https://lore.kernel.org/lkml/ZO%2FTe6LU1ENf58ZW@nvidia.com/ * tag 'for-linus-iommufd' of git://git.kernel.org/pub/scm/linux/kernel/git/jgg/iommufd: (34 commits) iommufd/selftest: Don't leak the platform device memory when unloading the module iommu/vt-d: Implement hw_info for iommu capability query iommufd/selftest: Add coverage for IOMMU_GET_HW_INFO ioctl iommufd: Add IOMMU_GET_HW_INFO iommu: Add new iommu op to get iommu hardware information iommu: Move dev_iommu_ops() to private header iommufd: Remove iommufd_ref_to_users() iommufd/selftest: Make the mock iommu driver into a real driver vfio: Support IO page table replacement iommufd/selftest: Add IOMMU_TEST_OP_ACCESS_REPLACE_IOAS coverage iommufd: Add iommufd_access_replace() API iommufd: Use iommufd_access_change_ioas in iommufd_access_destroy_object iommufd: Add iommufd_access_change_ioas(_id) helpers iommufd: Allow passing in iopt_access_list_id to iopt_remove_access() vfio: Do not allow !ops->dma_unmap in vfio_pin/unpin_pages() iommufd/selftest: Add a selftest for IOMMU_HWPT_ALLOC iommufd/selftest: Return the real idev id from selftest mock_domain iommufd: Add IOMMU_HWPT_ALLOC iommufd/selftest: Test iommufd_device_replace() iommufd: Make destroy_rwsem use a lock class per object type ...

vfio: align capability structures

2023-08-17T18:17:44+00:00

The VFIO_DEVICE_GET_INFO, VFIO_DEVICE_GET_REGION_INFO, and VFIO_IOMMU_GET_INFO ioctls fill in an info struct followed by capability structs: +------+---------+---------+-----+ | info | caps[0] | caps[1] | ... | +------+---------+---------+-----+ Both the info and capability struct sizes are not always multiples of sizeof(u64), leaving u64 fields in later capability structs misaligned. Userspace applications currently need to handle misalignment manually in order to support CPU architectures and programming languages with strict alignment requirements. Make life easier for userspace by ensuring alignment in the kernel. This is done by padding info struct definitions and by copying out zeroes after capability structs that are not aligned. The new layout is as follows: +------+---------+---+---------+-----+ | info | caps[0] | 0 | caps[1] | ... | +------+---------+---+---------+-----+ In this example caps[0] has a size that is not multiples of sizeof(u64), so zero padding is added to align the subsequent structure. Adding zero padding between structs does not break the uapi. The memory layout is specified by the info.cap_offset and caps[i].next fields filled in by the kernel. Applications use these field values to locate structs and are therefore unaffected by the addition of zero padding. Note that code that copies out info structs with padding is updated to always zero the struct and copy out as many bytes as userspace requested. This makes the code shorter and avoids potential information leaks by ensuring padding is initialized. Originally-by: Alex Williamson Signed-off-by: Stefan Hajnoczi Reviewed-by: Kevin Tian Acked-by: Jason Gunthorpe Link: https://lore.kernel.org/r/20230809203144.2880050-1-stefanha@redhat.com Signed-off-by: Alex Williamson

vfio: Support IO page table replacement

2023-07-28T16:31:24+00:00

Now both the physical path and the emulated path can support an IO page table replacement. Call iommufd_device_replace/iommufd_access_replace(), when vdev->iommufd_attached is true. Also update the VFIO_DEVICE_ATTACH_IOMMUFD_PT kdoc in the uAPI header. Link: https://lore.kernel.org/r/b5f01956ff161f76aa52c95b0fa1ad6eaca95c4a.1690523699.git.nicolinc@nvidia.com Reviewed-by: Kevin Tian Reviewed-by: Jason Gunthorpe Reviewed-by: Alex Williamson Signed-off-by: Nicolin Chen Signed-off-by: Jason Gunthorpe

vfio: Add VFIO_DEVICE_[AT|DE]TACH_IOMMUFD_PT

2023-07-25T16:20:37+00:00

This adds ioctl for userspace to attach device cdev fd to and detach from IOAS/hw_pagetable managed by iommufd. VFIO_DEVICE_ATTACH_IOMMUFD_PT: attach vfio device to IOAS or hw_pagetable managed by iommufd. Attach can be undo by VFIO_DEVICE_DETACH_IOMMUFD_PT or device fd close. VFIO_DEVICE_DETACH_IOMMUFD_PT: detach vfio device from the current attached IOAS or hw_pagetable managed by iommufd. Reviewed-by: Jason Gunthorpe Tested-by: Nicolin Chen Tested-by: Matthew Rosato Tested-by: Yanting Jiang Tested-by: Shameer Kolothum Tested-by: Terrence Xu Tested-by: Zhenzhong Duan Signed-off-by: Yi Liu Link: https://lore.kernel.org/r/20230718135551.6592-24-yi.l.liu@intel.com Signed-off-by: Alex Williamson

vfio: Add VFIO_DEVICE_BIND_IOMMUFD

2023-07-25T16:20:32+00:00

This adds ioctl for userspace to bind device cdev fd to iommufd. VFIO_DEVICE_BIND_IOMMUFD: bind device to an iommufd, hence gain DMA control provided by the iommufd. open_device op is called after bind_iommufd op. Tested-by: Nicolin Chen Tested-by: Matthew Rosato Tested-by: Yanting Jiang Tested-by: Shameer Kolothum Tested-by: Terrence Xu Tested-by: Zhenzhong Duan Signed-off-by: Yi Liu Reviewed-by: Jason Gunthorpe Link: https://lore.kernel.org/r/20230718135551.6592-23-yi.l.liu@intel.com Signed-off-by: Alex Williamson