Add a guest_memfd testcase to verify that faulting in private memory gets a SIGBUS. For now, test only the case where memory is private by default since KVM doesn't yet support in-place conversion. Cc: Ackerley Tng Signed-off-by: Sean Christopherson --- .../testing/selftests/kvm/guest_memfd_test.c | 62 ++++++++++++++----- 1 file changed, 46 insertions(+), 16 deletions(-) diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c index 5dd40b77dc07..b5a631aca933 100644 --- a/tools/testing/selftests/kvm/guest_memfd_test.c +++ b/tools/testing/selftests/kvm/guest_memfd_test.c @@ -40,17 +40,26 @@ static void test_file_read_write(int fd, size_t total_size) "pwrite on a guest_mem fd should fail"); } -static void test_mmap_supported(int fd, size_t total_size) +static void *test_mmap_common(int fd, size_t size) { - const char val = 0xaa; - char *mem; - size_t i; - int ret; + void *mem; - mem = mmap(NULL, total_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0); + mem = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0); TEST_ASSERT(mem == MAP_FAILED, "Copy-on-write not allowed by guest_memfd."); - mem = kvm_mmap(total_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd); + mem = kvm_mmap(size, PROT_READ | PROT_WRITE, MAP_SHARED, fd); + + return mem; +} + +static void test_mmap_supported(int fd, size_t total_size) +{ + const char val = 0xaa; + char *mem; + size_t i; + int ret; + + mem = test_mmap_common(fd, total_size); memset(mem, val, total_size); for (i = 0; i < total_size; i++) @@ -78,31 +87,47 @@ void fault_sigbus_handler(int signum) siglongjmp(jmpbuf, 1); } -static void test_fault_overflow(int fd, size_t total_size) +static void *test_fault_sigbus(int fd, size_t size) { struct sigaction sa_old, sa_new = { .sa_handler = fault_sigbus_handler, }; - size_t map_size = total_size * 4; - const char val = 0xaa; - char *mem; - size_t i; + void *mem; - mem = kvm_mmap(map_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd); + mem = test_mmap_common(fd, size); sigaction(SIGBUS, &sa_new, &sa_old); if (sigsetjmp(jmpbuf, 1) == 0) { - memset(mem, 0xaa, map_size); + memset(mem, 0xaa, size); TEST_ASSERT(false, "memset() should have triggered SIGBUS."); } sigaction(SIGBUS, &sa_old, NULL); + return mem; +} + +static void test_fault_overflow(int fd, size_t total_size) +{ + size_t map_size = total_size * 4; + const char val = 0xaa; + char *mem; + size_t i; + + mem = test_fault_sigbus(fd, map_size); + for (i = 0; i < total_size; i++) TEST_ASSERT_EQ(READ_ONCE(mem[i]), val); kvm_munmap(mem, map_size); } +static void test_fault_private(int fd, size_t total_size) +{ + void *mem = test_fault_sigbus(fd, total_size); + + kvm_munmap(mem, total_size); +} + static void test_mmap_not_supported(int fd, size_t total_size) { char *mem; @@ -274,9 +299,12 @@ static void __test_guest_memfd(struct kvm_vm *vm, uint64_t flags) gmem_test(file_read_write, vm, flags); - if (flags & GUEST_MEMFD_FLAG_MMAP) { + if (flags & GUEST_MEMFD_FLAG_MMAP && + flags & GUEST_MEMFD_FLAG_DEFAULT_SHARED) { gmem_test(mmap_supported, vm, flags); gmem_test(fault_overflow, vm, flags); + } else if (flags & GUEST_MEMFD_FLAG_MMAP) { + gmem_test(fault_private, vm, flags); } else { gmem_test(mmap_not_supported, vm, flags); } @@ -294,9 +322,11 @@ static void test_guest_memfd(unsigned long vm_type) __test_guest_memfd(vm, 0); - if (vm_check_cap(vm, KVM_CAP_GUEST_MEMFD_MMAP)) + if (vm_check_cap(vm, KVM_CAP_GUEST_MEMFD_MMAP)) { + __test_guest_memfd(vm, GUEST_MEMFD_FLAG_MMAP); __test_guest_memfd(vm, GUEST_MEMFD_FLAG_MMAP | GUEST_MEMFD_FLAG_DEFAULT_SHARED); + } kvm_vm_free(vm); } -- 2.51.0.536.g15c5d4f767-goog