From e49a6a2173346d316c0e65d054a3cda89d57cb53 Mon Sep 17 00:00:00 2001 From: Alexey Kardashevskiy Date: Thu, 13 Apr 2017 17:05:27 +1000 Subject: [PATCH] powerpc/powernv: Fix iommu table size calculation hook for small tables 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 Signed-off-by: Michael Ellerman --- 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 bc5466d447e7..16fd322b2eea 100644 --- a/arch/powerpc/platforms/powernv/pci-ioda.c +++ b/arch/powerpc/platforms/powernv/pci-ioda.c @@ -2440,7 +2440,8 @@ 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; -- 2.45.2