From: Shivank Garg Add NUMA helpers to probe for support/availability and to check if the test is running on a multi-node system. The APIs will be used to verify guest_memfd NUMA support. Signed-off-by: Shivank Garg [sean: land helpers in numaif.h, add comments, tweak names] Signed-off-by: Sean Christopherson --- tools/testing/selftests/kvm/include/numaif.h | 52 ++++++++++++++++++++ 1 file changed, 52 insertions(+) diff --git a/tools/testing/selftests/kvm/include/numaif.h b/tools/testing/selftests/kvm/include/numaif.h index 1554003c40a1..29572a6d789c 100644 --- a/tools/testing/selftests/kvm/include/numaif.h +++ b/tools/testing/selftests/kvm/include/numaif.h @@ -4,6 +4,8 @@ #ifndef SELFTEST_KVM_NUMAIF_H #define SELFTEST_KVM_NUMAIF_H +#include + #include #include "kvm_syscalls.h" @@ -28,4 +30,54 @@ KVM_SYSCALL_DEFINE(mbind, 6, void *, addr, unsigned long, size, int, mode, const unsigned long *, nodemask, unsigned long, maxnode, unsigned int, flags); +static inline int get_max_numa_node(void) +{ + struct dirent *de; + int max_node = 0; + DIR *d; + + /* + * Assume there's a single node if the kernel doesn't support NUMA, + * or if no nodes are found. + */ + d = opendir("/sys/devices/system/node"); + if (!d) + return 0; + + while ((de = readdir(d)) != NULL) { + int node_id; + char *endptr; + + if (strncmp(de->d_name, "node", 4) != 0) + continue; + + node_id = strtol(de->d_name + 4, &endptr, 10); + if (*endptr != '\0') + continue; + + if (node_id > max_node) + max_node = node_id; + } + closedir(d); + + return max_node; +} + +static bool is_numa_available(void) +{ + /* + * Probe for NUMA by doing a dummy get_mempolicy(). If the syscall + * fails with ENOSYS, then the kernel was built without NUMA support. + * if the syscall fails with EPERM, then the process/user lacks the + * necessary capabilities (CAP_SYS_NICE). + */ + return !get_mempolicy(NULL, NULL, 0, NULL, 0) || + (errno != ENOSYS && errno != EPERM); +} + +static inline bool is_multi_numa_node_system(void) +{ + return is_numa_available() && get_max_numa_node() >= 1; +} + #endif /* SELFTEST_KVM_NUMAIF_H */ -- 2.51.0.710.ga91ca5db03-goog