commit dce043c07c upstream.
switch_to_super_page() assumes the memory range it's working on is aligned
to the target large page level. Unfortunately, __domain_mapping() doesn't
take this into account when using it, and will pass unaligned ranges
ultimately freeing a PTE range larger than expected.
Take for example a mapping with the following iov_pfn range [0x3fe400,
0x4c0600), which should be backed by the following mappings:
iov_pfn [0x3fe400, 0x3fffff] covered by 2MiB pages
iov_pfn [0x400000, 0x4bffff] covered by 1GiB pages
iov_pfn [0x4c0000, 0x4c05ff] covered by 2MiB pages
Under this circumstance, __domain_mapping() will pass [0x400000, 0x4c05ff]
to switch_to_super_page() at a 1 GiB granularity, which will in turn
free PTEs all the way to iov_pfn 0x4fffff.
Mitigate this by rounding down the iov_pfn range passed to
switch_to_super_page() in __domain_mapping()
to the target large page level.
Additionally add range alignment checks to switch_to_super_page.
Fixes: 9906b9352a ("iommu/vt-d: Avoid duplicate removing in __domain_mapping()")
Signed-off-by: Eugene Koira <eugkoira@amazon.com>
Cc: stable@vger.kernel.org
Reviewed-by: Nicolas Saenz Julienne <nsaenz@amazon.com>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Link: https://lore.kernel.org/r/20250826143816.38686-1-eugkoira@amazon.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
c023b4f444