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

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
  ...

2 files changed, 103 insertions, 0 deletions

diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 98ebba80cfa1..b4ba0c0cbab6 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -45,6 +45,8 @@ enum {
 	IOMMUFD_CMD_IOAS_UNMAP,
 	IOMMUFD_CMD_OPTION,
 	IOMMUFD_CMD_VFIO_IOAS,
+	IOMMUFD_CMD_HWPT_ALLOC,
+	IOMMUFD_CMD_GET_HW_INFO,
 };
 
 /**
@@ -344,4 +346,99 @@ struct iommu_vfio_ioas {
 	__u16 __reserved;
 };
 #define IOMMU_VFIO_IOAS _IO(IOMMUFD_TYPE, IOMMUFD_CMD_VFIO_IOAS)
+
+/**
+ * struct iommu_hwpt_alloc - ioctl(IOMMU_HWPT_ALLOC)
+ * @size: sizeof(struct iommu_hwpt_alloc)
+ * @flags: Must be 0
+ * @dev_id: The device to allocate this HWPT for
+ * @pt_id: The IOAS to connect this HWPT to
+ * @out_hwpt_id: The ID of the new HWPT
+ * @__reserved: Must be 0
+ *
+ * Explicitly allocate a hardware page table object. This is the same object
+ * type that is returned by iommufd_device_attach() and represents the
+ * underlying iommu driver's iommu_domain kernel object.
+ *
+ * A HWPT will be created with the IOVA mappings from the given IOAS.
+ */
+struct iommu_hwpt_alloc {
+	__u32 size;
+	__u32 flags;
+	__u32 dev_id;
+	__u32 pt_id;
+	__u32 out_hwpt_id;
+	__u32 __reserved;
+};
+#define IOMMU_HWPT_ALLOC _IO(IOMMUFD_TYPE, IOMMUFD_CMD_HWPT_ALLOC)
+
+/**
+ * struct iommu_hw_info_vtd - Intel VT-d hardware information
+ *
+ * @flags: Must be 0
+ * @__reserved: Must be 0
+ *
+ * @cap_reg: Value of Intel VT-d capability register defined in VT-d spec
+ *           section 11.4.2 Capability Register.
+ * @ecap_reg: Value of Intel VT-d capability register defined in VT-d spec
+ *            section 11.4.3 Extended Capability Register.
+ *
+ * User needs to understand the Intel VT-d specification to decode the
+ * register value.
+ */
+struct iommu_hw_info_vtd {
+	__u32 flags;
+	__u32 __reserved;
+	__aligned_u64 cap_reg;
+	__aligned_u64 ecap_reg;
+};
+
+/**
+ * enum iommu_hw_info_type - IOMMU Hardware Info Types
+ * @IOMMU_HW_INFO_TYPE_NONE: Used by the drivers that do not report hardware
+ *                           info
+ * @IOMMU_HW_INFO_TYPE_INTEL_VTD: Intel VT-d iommu info type
+ */
+enum iommu_hw_info_type {
+	IOMMU_HW_INFO_TYPE_NONE,
+	IOMMU_HW_INFO_TYPE_INTEL_VTD,
+};
+
+/**
+ * struct iommu_hw_info - ioctl(IOMMU_GET_HW_INFO)
+ * @size: sizeof(struct iommu_hw_info)
+ * @flags: Must be 0
+ * @dev_id: The device bound to the iommufd
+ * @data_len: Input the length of a user buffer in bytes. Output the length of
+ *            data that kernel supports
+ * @data_uptr: User pointer to a user-space buffer used by the kernel to fill
+ *             the iommu type specific hardware information data
+ * @out_data_type: Output the iommu hardware info type as defined in the enum
+ *                 iommu_hw_info_type.
+ * @__reserved: Must be 0
+ *
+ * Query an iommu type specific hardware information data from an iommu behind
+ * a given device that has been bound to iommufd. This hardware info data will
+ * be used to sync capabilities between the virtual iommu and the physical
+ * iommu, e.g. a nested translation setup needs to check the hardware info, so
+ * a guest stage-1 page table can be compatible with the physical iommu.
+ *
+ * To capture an iommu type specific hardware information data, @data_uptr and
+ * its length @data_len must be provided. Trailing bytes will be zeroed if the
+ * user buffer is larger than the data that kernel has. Otherwise, kernel only
+ * fills the buffer using the given length in @data_len. If the ioctl succeeds,
+ * @data_len will be updated to the length that kernel actually supports,
+ * @out_data_type will be filled to decode the data filled in the buffer
+ * pointed by @data_uptr. Input @data_len == zero is allowed.
+ */
+struct iommu_hw_info {
+	__u32 size;
+	__u32 flags;
+	__u32 dev_id;
+	__u32 data_len;
+	__aligned_u64 data_uptr;
+	__u32 out_data_type;
+	__u32 __reserved;
+};
+#define IOMMU_GET_HW_INFO _IO(IOMMUFD_TYPE, IOMMUFD_CMD_GET_HW_INFO)
 #endif
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index f9c6f3e2cf6e..afc1369216d9 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -940,6 +940,12 @@ struct vfio_device_bind_iommufd {
  * Undo by VFIO_DEVICE_DETACH_IOMMUFD_PT or device fd close.  This is only
  * allowed on cdev fds.
  *
+ * If a vfio device is currently attached to a valid hw_pagetable, without doing
+ * a VFIO_DEVICE_DETACH_IOMMUFD_PT, a second VFIO_DEVICE_ATTACH_IOMMUFD_PT ioctl
+ * passing in another hw_pagetable (hwpt) id is allowed. This action, also known
+ * as a hw_pagetable replacement, will replace the device's currently attached
+ * hw_pagetable with a new hw_pagetable corresponding to the given pt_id.
+ *
  * Return: 0 on success, -errno on failure.
  */
 struct vfio_device_attach_iommufd_pt {