diff options
| author | Alexey Kardashevskiy <aik@ozlabs.ru> | 2020-03-24 17:39:12 +1100 |
|---|---|---|
| committer | David Gibson <david@gibson.dropbear.id.au> | 2020-04-07 08:55:10 +1000 |
| commit | 79178edd2a0b012c5cd27e0168beb83ef4b617ef (patch) | |
| tree | 2196dcc3ed580bf7e8baec82d5ded78871bd85b2 | |
| parent | 3b4f50bd7d16322a109a026a87a945dff660f38b (diff) | |
| download | qemu-79178edd2a0b012c5cd27e0168beb83ef4b617ef.zip | |
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>
| -rw-r--r-- | hw/vfio/spapr.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/hw/vfio/spapr.c b/hw/vfio/spapr.c index 33692fc86f..2900bd1941 100644 --- a/hw/vfio/spapr.c +++ b/hw/vfio/spapr.c @@ -147,7 +147,7 @@ int vfio_spapr_create_window(VFIOContainer *container, { int ret = 0; IOMMUMemoryRegion *iommu_mr = IOMMU_MEMORY_REGION(section->mr); - uint64_t pagesize = memory_region_iommu_get_min_page_size(iommu_mr); + uint64_t pagesize = memory_region_iommu_get_min_page_size(iommu_mr), pgmask; unsigned entries, bits_total, bits_per_level, max_levels; struct vfio_iommu_spapr_tce_create create = { .argsz = sizeof(create) }; long rampagesize = qemu_minrampagesize(); @@ -159,8 +159,8 @@ int vfio_spapr_create_window(VFIOContainer *container, if (pagesize > rampagesize) { pagesize = rampagesize; } - pagesize = 1ULL << (63 - clz64(container->pgsizes & - (pagesize | (pagesize - 1)))); + pgmask = container->pgsizes & (pagesize | (pagesize - 1)); + pagesize = pgmask ? (1ULL << (63 - clz64(pgmask))) : 0; if (!pagesize) { error_report("Host doesn't support page size 0x%"PRIx64 ", the supported mask is 0x%lx", |