KVM: selftests: Verify that reads to inaccessible guest_memfd VMAs SIGBUS
Expand the guest_memfd negative testcases for overflow and MAP_PRIVATE to
verify that reads to inaccessible memory also get a SIGBUS.
Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Tested-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: Lisa Wang <wyihan@google.com>
Tested-by: Lisa Wang <wyihan@google.com>
Link: https://lore.kernel.org/r/20251003232606.4070510-14-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c
index f5372fd..e7d9aeb 100644
--- a/tools/testing/selftests/kvm/guest_memfd_test.c
+++ b/tools/testing/selftests/kvm/guest_memfd_test.c
@@ -84,6 +84,7 @@ static void test_fault_sigbus(int fd, size_t accessible_size, size_t map_size)
mem = kvm_mmap(map_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd);
TEST_EXPECT_SIGBUS(memset(mem, val, map_size));
+ TEST_EXPECT_SIGBUS((void)READ_ONCE(mem[accessible_size]));
for (i = 0; i < accessible_size; i++)
TEST_ASSERT_EQ(READ_ONCE(mem[i]), val);
