[PATCH kvm-next V11 7/7] KVM: guest_memfd: selftests: Add tests for mmap and NUMA policy support

Shivank Garg
2025-08-27T17:57:51Z

Add tests for NUMA memory policy binding and NUMA aware allocation in
guest_memfd. This extends the existing selftests by adding proper
validation for:
- KVM GMEM set_policy and get_policy() vm_ops functionality using
mbind() and get_mempolicy()
- NUMA policy application before and after memory allocation

These tests help ensure NUMA support for guest_memfd works correctly.

Signed-off-by: Shivank Garg <shivankg@amd.com>
---
tools/testing/selftests/kvm/Makefile.kvm | 1 +
.../testing/selftests/kvm/guest_memfd_test.c | 121 ++++++++++++++++++
2 files changed, 122 insertions(+)

diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
index 90f03f00cb04..c46cef2a7cd7 100644
--- a/tools/testing/selftests/kvm/Makefile.kvm
+++ b/tools/testing/selftests/kvm/Makefile.kvm
@@ -275,6 +275,7 @@ pgste-option = $(call try-run, echo 'int main(void) { return 0; }' | \
$(CC) -Werror -Wl$(comma)--s390-pgste -x c - -o "$$TMP",-Wl$(comma)--s390-pgste)

LDLIBS += -ldl
+LDLIBS += -lnuma
LDFLAGS += -pthread $(no-pie-option) $(pgste-option)

LIBKVM_C := $(filter %.c,$(LIBKVM))
diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c
index b3ca6737f304..9640d04ec293 100644
--- a/tools/testing/selftests/kvm/guest_memfd_test.c
+++ b/tools/testing/selftests/kvm/guest_memfd_test.c
@@ -7,6 +7,8 @@
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
+#include <numa.h>
+#include <numaif.h>
#include <errno.h>
#include <stdio.h>
#include <fcntl.h>
@@ -19,6 +21,7 @@
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
+#include <sys/syscall.h>

#include "kvm_util.h"
#include "test_util.h"
@@ -72,6 +75,122 @@ static void test_mmap_supported(int fd, size_t page_size, size_t total_size)
TEST_ASSERT(!ret, "munmap() should succeed.");
}

+#define TEST_REQUIRE_NUMA_MULTIPLE_NODES() \
+ TEST_REQUIRE(numa_available() != -1 && numa_max_node() >= 1)
+
+static void test_mbind(int fd, size_t page_size, size_t total_size)
+{
+ unsigned long nodemask = 1; /* nid: 0 */
+ unsigned long maxnode = 8;
+ unsigned long get_nodemask;
+ int get_policy;
+ char *mem;
+ int ret;
+
+ TEST_REQUIRE_NUMA_MULTIPLE_NODES();
+
+ mem = mmap(NULL, total_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+ TEST_ASSERT(mem != MAP_FAILED, "mmap for mbind test should succeed");
+
+ /* Test MPOL_INTERLEAVE policy */
+ ret = syscall(__NR_mbind, mem, page_size * 2, MPOL_INTERLEAVE,
+ &nodemask, maxnode, 0);
+ TEST_ASSERT(!ret, "mbind with INTERLEAVE to node 0 should succeed");
+ ret = syscall(__NR_get_mempolicy, &get_policy, &get_nodemask,
+ maxnode, mem, MPOL_F_ADDR);
+ TEST_ASSERT(!ret && get_policy == MPOL_INTERLEAVE && get_nodemask == nodemask,
+ "Policy should be MPOL_INTERLEAVE and nodes match");
+
+ /* Test basic MPOL_BIND policy */
+ ret = syscall(__NR_mbind, mem + page_size * 2, page_size * 2, MPOL_BIND,
+ &nodemask, maxnode, 0);
+ TEST_ASSERT(!ret, "mbind with MPOL_BIND to node 0 should succeed");
+ ret = syscall(__NR_get_mempolicy, &get_policy, &get_nodemask,
+ maxnode, mem + page_size * 2, MPOL_F_ADDR);
+ TEST_ASSERT(!ret && get_policy == MPOL_BIND && get_nodemask == nodemask,
+ "Policy should be MPOL_BIND and nodes match");
+
+ /* Test MPOL_DEFAULT policy */
+ ret = syscall(__NR_mbind, mem, total_size, MPOL_DEFAULT, NULL, 0, 0);
+ TEST_ASSERT(!ret, "mbind with MPOL_DEFAULT should succeed");
+ ret = syscall(__NR_get_mempolicy, &get_policy, &get_nodemask,
+ maxnode, mem, MPOL_F_ADDR);
+ TEST_ASSERT(!ret && get_policy == MPOL_DEFAULT && get_nodemask == 0,
+ "Policy should be MPOL_DEFAULT and nodes zero");
+
+ /* Test with invalid policy */
+ ret = syscall(__NR_mbind, mem, page_size, 999, &nodemask, maxnode, 0);
+ TEST_ASSERT(ret == -1 && errno == EINVAL,
+ "mbind with invalid policy should fail with EINVAL");
+
+ TEST_ASSERT(munmap(mem, total_size) == 0, "munmap should succeed");
+}
+
+static void test_numa_allocation(int fd, size_t page_size, size_t total_size)
+{
+ unsigned long node0_mask = 1; /* Node 0 */
+ unsigned long node1_mask = 2; /* Node 1 */
+ unsigned long maxnode = 8;
+ void *pages[4];
+ int status[4];
+ char *mem;
+ int ret, i;
+
+ TEST_REQUIRE_NUMA_MULTIPLE_NODES();
+
+ /* Clean slate: deallocate all file space, if any */
+ ret = fallocate(fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, 0, total_size);
+ TEST_ASSERT(!ret, "fallocate(PUNCH_HOLE) should succeed");
+
+ mem = mmap(NULL, total_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+ TEST_ASSERT(mem != MAP_FAILED, "mmap should succeed");
+
+ for (i = 0; i < 4; i++)
+ pages[i] = (char *)mem + page_size * i;
+
+ /* Set NUMA policy after allocation */
+ memset(mem, 0xaa, page_size);
+ ret = syscall(__NR_mbind, pages[0], page_size, MPOL_BIND, &node0_mask, maxnode, 0);
+ TEST_ASSERT(!ret, "mbind after allocation page 0 to node 0 should succeed");
+ ret = fallocate(fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, 0, page_size);
+ TEST_ASSERT(!ret, "fallocate(PUNCH_HOLE) should succeed");
+
+ /* Set NUMA policy before allocation */
+ ret = syscall(__NR_mbind, pages[0], page_size * 2, MPOL_BIND, &node1_mask, maxnode, 0);
+ TEST_ASSERT(!ret, "mbind page 0, 1 to node 1 should succeed");
+ ret = syscall(__NR_mbind, pages[2], page_size * 2, MPOL_BIND, &node0_mask, maxnode, 0);
+ TEST_ASSERT(!ret, "mbind page 2, 3 to node 0 should succeed");
+ memset(mem, 0xaa, total_size);
+
+ /* Validate if pages are allocated on specified NUMA nodes */
+ ret = syscall(__NR_move_pages, 0, 4, pages, NULL, status, 0);
+ TEST_ASSERT(ret >= 0, "move_pages should succeed for status check");
+ TEST_ASSERT(status[0] == 1, "Page 0 should be allocated on node 1");
+ TEST_ASSERT(status[1] == 1, "Page 1 should be allocated on node 1");
+ TEST_ASSERT(status[2] == 0, "Page 2 should be allocated on node 0");
+ TEST_ASSERT(status[3] == 0, "Page 3 should be allocated on node 0");
+
+ /* Punch hole for all pages */
+ ret = fallocate(fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, 0, total_size);
+ TEST_ASSERT(!ret, "fallocate(PUNCH_HOLE) should succeed");
+
+ /* Change NUMA policy nodes and reallocate */
+ ret = syscall(__NR_mbind, pages[0], page_size * 2, MPOL_BIND, &node0_mask, maxnode, 0);
+ TEST_ASSERT(!ret, "mbind page 0, 1 to node 0 should succeed");
+ ret = syscall(__NR_mbind, pages[2], page_size * 2, MPOL_BIND, &node1_mask, maxnode, 0);
+ TEST_ASSERT(!ret, "mbind page 2, 3 to node 1 should succeed");
+ memset(mem, 0xaa, total_size);
+
+ ret = syscall(__NR_move_pages, 0, 4, pages, NULL, status, 0);
+ TEST_ASSERT(ret >= 0, "move_pages should succeed after reallocation");
+ TEST_ASSERT(status[0] == 0, "Page 0 should be allocated on node 0");
+ TEST_ASSERT(status[1] == 0, "Page 1 should be allocated on node 0");
+ TEST_ASSERT(status[2] == 1, "Page 2 should be allocated on node 1");
+ TEST_ASSERT(status[3] == 1, "Page 3 should be allocated on node 1");
+
+ TEST_ASSERT(munmap(mem, total_size) == 0, "munmap should succeed");
+}
+
static sigjmp_buf jmpbuf;
void fault_sigbus_handler(int signum)
{
@@ -286,6 +405,8 @@ static void test_guest_memfd(unsigned long vm_type)
if (flags & GUEST_MEMFD_FLAG_MMAP) {
test_mmap_supported(fd, page_size, total_size);
test_fault_overflow(fd, page_size, total_size);
+ test_mbind(fd, page_size, total_size);
+ test_numa_allocation(fd, page_size, total_size);
} else {
test_mmap_not_supported(fd, page_size, total_size);
}
--
2.43.0