tree 2196dcc3ed580bf7e8baec82d5ded78871bd85b2
parent 3b4f50bd7d16322a109a026a87a945dff660f38b
author Alexey Kardashevskiy <aik@ozlabs.ru> 1585031952 +1100
committer David Gibson <david@gibson.dropbear.id.au> 1586213710 +1000

vfio/spapr: Fix page size calculation

Coverity detected an issue (CID 1421903) with potential call of clz64(0)
which returns 64 which make it do "<<" with a negative number.

This checks the mask and avoids undefined behaviour.

In practice pgsizes and memory_region_iommu_get_min_page_size() always
have some common page sizes and even if they did not, the resulting page
size would be 0x8000.0000.0000.0000 (gcc 9.2) and
ioctl(VFIO_IOMMU_SPAPR_TCE_CREATE) would fail anyway.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Message-Id: <20200324063912.25063-1-aik@ozlabs.ru>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>