At the moment the userspace can request a table smaller than a page size
and this value will be stored as kvmppc_spapr_tce_table::size.
However the actual allocated size will still be aligned to the system
page size as alloc_page() is used there.
This aligns the table size up to the system page size. It should not
change the existing behaviour but when in-kernel TCE acceleration patchset
reaches the upstream kernel, this will allow small TCE tables be
accelerated as well: PCI IODA iommu_table allocator already aligns
the size and, without this patch, an IOMMU group won't attach to LIOBN
due to the mismatching table size.
Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxxxx>
---
For sake of bisectability (otherwise in-kernel acceleration won't work
hugepages braking DMA completely), this is better be put before
[PATCH kernel v11 00/10] powerpc/kvm/vfio: Enable in-kernel acceleration
---
arch/powerpc/kvm/book3s_64_vio.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c
index aea3a5b74fb6..45941af9c6d7 100644
--- a/arch/powerpc/kvm/book3s_64_vio.c
+++ b/arch/powerpc/kvm/book3s_64_vio.c
@@ -333,7 +333,7 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
return -EBUSY;
}
- size = args->size;
+ size = _ALIGN_UP(args->size, PAGE_SIZE >> 3);
npages = kvmppc_tce_pages(size);
ret = kvmppc_account_memlimit(kvmppc_stt_pages(npages), true);
if (ret) {
--
2.11.0
