Increase 'maxnode' when using 'get_mempolicy' syscall in guest_memfd mmap and NUMA policy tests to fix a failure on one Intel GNR platform.
On a CXL-capable platform, the memory affinity of CXL memory regions may not be covered by the SRAT. Since each CXL memory region is enumerated via a CFMWS table, at early boot the kernel parses all CFMWS tables to detect all CXL memory regions and assigns a 'faked' NUMA node for each of them, starting from the highest NUMA node ID enumerated via the SRAT. This increases the 'nr_node_ids'. E.g., on the aforementioned Intel GNR platform which has 4 NUMA nodes and 18 CFMWS tables, it increases to 22. This results in the 'get_mempolicy' syscall failure on that platform, because currently 'maxnode' is hard-coded to 8 but the 'get_mempolicy' syscall requires the 'maxnode' to be not smaller than the 'nr_node_ids'. Increase the 'maxnode' to the number of bits of 'unsigned long' (i.e., 64 on 64-bit systems) to fix this. Note the 'nodemask' is 'unsigned long', so it makes sense to set 'maxnode' to bits of 'unsigned long' anyway. This may not cover all systems. Perhaps a better way is to always set the 'nodemask' and 'maxnode' based on the actual maximum NUMA node ID on the system, but for now just do the simple way. Signed-off-by: Kai Huang <[email protected]> --- tools/testing/selftests/kvm/guest_memfd_test.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c index 618c937f3c90..b434612bc3ec 100644 --- a/tools/testing/selftests/kvm/guest_memfd_test.c +++ b/tools/testing/selftests/kvm/guest_memfd_test.c @@ -80,7 +80,7 @@ static void test_mbind(int fd, size_t total_size) { const unsigned long nodemask_0 = 1; /* nid: 0 */ unsigned long nodemask = 0; - unsigned long maxnode = 8; + unsigned long maxnode = sizeof(nodemask) * 8; int policy; char *mem; int ret; base-commit: a91cc48246605af9aeef1edd32232976d74d9502 -- 2.53.0
