KVM: PPC: Align the table size to system page size

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.
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

arch/powerpc/kvm/book3s_64_vio.c

@@ -164,7 +164,7 @@ 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) {