When the userspace requests a small TCE table (which takes less than
the system page size) and more than 1 TCE level, the existing code
returns a single page size which is a bug as each additional TCE level
requires at least one page and this is what
pnv_pci_ioda2_table_alloc_pages() does. And we end up seeing
WARN_ON(!ret && ((*ptbl)->it_allocated_size != table_size))
in drivers/vfio/vfio_iommu_spapr_tce.c.
This replaces incorrect _ALIGN_UP() (which aligns zero up to zero) with
max_t() to fix the bug.
Besides removing WARN_ON(), there should be no other changes in
behaviour.
Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
---
arch/powerpc/platforms/powernv/pci-ioda.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c
b/arch/powerpc/platforms/powernv/pci-ioda.c
index 6d0da5dfc955..a0d046adcf45 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -2538,7 +2538,8 @@ static unsigned long pnv_pci_ioda2_get_table_size(__u32
page_shift,
tce_table_size /= direct_table_size;
tce_table_size <<= 3;
- tce_table_size = _ALIGN_UP(tce_table_size, direct_table_size);
+ tce_table_size = max_t(unsigned long,
+ tce_table_size, direct_table_size);
}
return bytes;
--
2.11.0
