powerpc/powernv: Override pcibios_default_alignment() to force PCI devices to be page aligned

Override pcibios_default_alignment() to set default alignment to PAGE_SIZE
for all PCI devices on PowerNV platform.  Thus sub-page BARs would not
share a page and could be mapped into guest when VFIO passthrough them.

Signed-off-by: Yongji Xie <elohimes@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 6901a06..0529d56 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -3287,6 +3287,11 @@
 	}
 }
 
+static resource_size_t pnv_pci_default_alignment(void)
+{
+	return PAGE_SIZE;
+}
+
 #ifdef CONFIG_PCI_IOV
 static resource_size_t pnv_pci_iov_resource_alignment(struct pci_dev *pdev,
 						      int resno)
@@ -3820,6 +3825,8 @@
 		hose->controller_ops = pnv_pci_ioda_controller_ops;
 	}
 
+	ppc_md.pcibios_default_alignment = pnv_pci_default_alignment;
+
 #ifdef CONFIG_PCI_IOV
 	ppc_md.pcibios_fixup_sriov = pnv_pci_ioda_fixup_iov_resources;
 	ppc_md.pcibios_iov_resource_alignment = pnv_pci_iov_resource_alignment;