powerpc/powernv/npu: Fix oops in pnv_try_setup_npu_table_group()

fbarrat · mpe · commit 6bca51591751 · 2019-01-11T23:45:00.000+11:00
With a recent change around IOMMU group, a system with an opencapi adapter is no longer booting and we get a kernel oops: BUG: Kernel NULL pointer dereference at 0x00000028 Faulting instruction address: 0xc0000000000aa38c ... NIP pnv_try_setup_npu_table_group+0x1c/0x1a0 LR pnv_pci_ioda_fixup+0x1f8/0x660 Call Trace: pnv_try_setup_npu_table_group+0x60/0x pnv_pci_ioda_fixup+0x20c/0x660 pcibios_resource_survey+0x2c8/0x31c pcibios_init+0xb0/0xe4 do_one_initcall+0x64/0x264 kernel_init_freeable+0x36c/0x468 kernel_init+0x2c/0x148 ret_from_kernel_thread+0x5c/0x68 An opencapi device is using a device PE, so the current code breaks because pe->pbus is not defined. More generally, there's no need to define an IOMMU group for opencapi, as the device sends real addresses directly (admittedly, the virtualization story is yet to be written). So let's fix it by skipping the IOMMU group setup for opencapi PHBs. Fixes: 0bd9716 ("powerpc/powernv/npu: Add compound IOMMU groups") Signed-off-by: Frederic Barrat <fbarrat@linux.ibm.com> Reviewed-by: Greg Kurz <groug@kaod.org> Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -2681,7 +2681,8 @@ static void pnv_pci_ioda_setup_iommu_api(void)
 	list_for_each_entry(hose, &hose_list, list_node) {
 		phb = hose->private_data;
 
-		if (phb->type == PNV_PHB_NPU_NVLINK)
+		if (phb->type == PNV_PHB_NPU_NVLINK ||
+		    phb->type == PNV_PHB_NPU_OCAPI)
 			continue;
 
 		list_for_each_entry(pe, &phb->ioda.pe_list, list) {
