Commit 4004497c authored by Brett Creeley's avatar Brett Creeley Committed by Alex Williamson
Browse files

vfio/pds: Fix calculations in pds_vfio_dirty_sync 



The incorrect check is being done for comparing the
iova/length being requested to sync. This can cause
the dirty sync operation to fail. Fix this by making
sure the iova offset added to the requested sync
length doesn't exceed the region_size.

Also, the region_start is assumed to always be at 0.
This can cause dirty tracking to fail because the
device/driver bitmap offset always starts at 0,
however, the region_start/iova may not. Fix this by
determining the iova offset from region_start to
determine the bitmap offset.

Fixes: f232836a ("vfio/pds: Add support for dirty page tracking")
Signed-off-by: default avatarBrett Creeley <brett.creeley@amd.com>
Signed-off-by: default avatarShannon Nelson <shannon.nelson@amd.com>
Link: https://lore.kernel.org/r/20231117001207.2793-2-brett.creeley@amd.com


Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 33cc938e

drivers/vfio/pci/pds/dirty.c

+3 −3
Original line number Diff line number Diff line
@@ -478,8 +478,7 @@ static int pds_vfio_dirty_sync(struct pds_vfio_pci_device *pds_vfio, 
		pds_vfio->vf_id, iova, length, pds_vfio->dirty.region_page_size,

		pages, bitmap_size);



	if (!length || ((dirty->region_start + iova + length) >

			(dirty->region_start + dirty->region_size))) {

	if (!length || ((iova - dirty->region_start + length) > dirty->region_size)) {

		dev_err(dev, "Invalid iova 0x%lx and/or length 0x%lx to sync\n",

			iova, length);

		return -EINVAL;
@@ -496,7 +495,8 @@ static int pds_vfio_dirty_sync(struct pds_vfio_pci_device *pds_vfio, 
		return -EINVAL;

	}



	bmp_offset = DIV_ROUND_UP(iova / dirty->region_page_size, sizeof(u64));

	bmp_offset = DIV_ROUND_UP((iova - dirty->region_start) /

				  dirty->region_page_size, sizeof(u64));



	dev_dbg(dev,

		"Syncing dirty bitmap, iova 0x%lx length 0x%lx, bmp_offset %llu bmp_bytes %llu\n",