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authorJoao Martins <joao.m.martins@oracle.com>2023-10-24 15:50:58 +0200
committerJason Gunthorpe <jgg@nvidia.com>2023-10-24 16:58:43 +0200
commitb9a60d6f850e4470017b60f731220a58cda199aa (patch)
tree59a8dcf3cb7984e637a9a5c3616c78c25a8d85e5 /include
parentiommufd: Add IOMMU_HWPT_SET_DIRTY_TRACKING (diff)
downloadlinux-b9a60d6f850e4470017b60f731220a58cda199aa.tar.xz
linux-b9a60d6f850e4470017b60f731220a58cda199aa.zip
iommufd: Add IOMMU_HWPT_GET_DIRTY_BITMAP
Connect a hw_pagetable to the IOMMU core dirty tracking read_and_clear_dirty iommu domain op. It exposes all of the functionality for the UAPI that read the dirtied IOVAs while clearing the Dirty bits from the PTEs. In doing so, add an IO pagetable API iopt_read_and_clear_dirty_data() that performs the reading of dirty IOPTEs for a given IOVA range and then copying back to userspace bitmap. Underneath it uses the IOMMU domain kernel API which will read the dirty bits, as well as atomically clearing the IOPTE dirty bit and flushing the IOTLB at the end. The IOVA bitmaps usage takes care of the iteration of the bitmaps user pages efficiently and without copies. Within the iterator function we iterate over io-pagetable contigous areas that have been mapped. Contrary to past incantation of a similar interface in VFIO the IOVA range to be scanned is tied in to the bitmap size, thus the application needs to pass a appropriately sized bitmap address taking into account the iova range being passed *and* page size ... as opposed to allowing bitmap-iova != iova. Link: https://lore.kernel.org/r/20231024135109.73787-8-joao.m.martins@oracle.com Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Diffstat (limited to 'include')
-rw-r--r--include/uapi/linux/iommufd.h35
1 files changed, 35 insertions, 0 deletions
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 5c82b68c88f3..dce38e32ca84 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -48,6 +48,7 @@ enum {
IOMMUFD_CMD_HWPT_ALLOC,
IOMMUFD_CMD_GET_HW_INFO,
IOMMUFD_CMD_HWPT_SET_DIRTY_TRACKING,
+ IOMMUFD_CMD_HWPT_GET_DIRTY_BITMAP,
};
/**
@@ -481,4 +482,38 @@ struct iommu_hwpt_set_dirty_tracking {
};
#define IOMMU_HWPT_SET_DIRTY_TRACKING _IO(IOMMUFD_TYPE, \
IOMMUFD_CMD_HWPT_SET_DIRTY_TRACKING)
+
+/**
+ * struct iommu_hwpt_get_dirty_bitmap - ioctl(IOMMU_HWPT_GET_DIRTY_BITMAP)
+ * @size: sizeof(struct iommu_hwpt_get_dirty_bitmap)
+ * @hwpt_id: HW pagetable ID that represents the IOMMU domain
+ * @flags: Must be zero
+ * @__reserved: Must be 0
+ * @iova: base IOVA of the bitmap first bit
+ * @length: IOVA range size
+ * @page_size: page size granularity of each bit in the bitmap
+ * @data: bitmap where to set the dirty bits. The bitmap bits each
+ * represent a page_size which you deviate from an arbitrary iova.
+ *
+ * Checking a given IOVA is dirty:
+ *
+ * data[(iova / page_size) / 64] & (1ULL << ((iova / page_size) % 64))
+ *
+ * Walk the IOMMU pagetables for a given IOVA range to return a bitmap
+ * with the dirty IOVAs. In doing so it will also by default clear any
+ * dirty bit metadata set in the IOPTE.
+ */
+struct iommu_hwpt_get_dirty_bitmap {
+ __u32 size;
+ __u32 hwpt_id;
+ __u32 flags;
+ __u32 __reserved;
+ __aligned_u64 iova;
+ __aligned_u64 length;
+ __aligned_u64 page_size;
+ __aligned_u64 data;
+};
+#define IOMMU_HWPT_GET_DIRTY_BITMAP _IO(IOMMUFD_TYPE, \
+ IOMMUFD_CMD_HWPT_GET_DIRTY_BITMAP)
+
#endif