Re: [PATCH v3 2/2] selftests: kvm: Add mem_slot_test test

On Tue, Apr 07, 2020 at 12:37:31PM -0300, Wainer dos Santos Moschetta wrote:

This patch introduces the mem_slot_test test which checks an VM can have added memory slots up to the limit defined in KVM_CAP_NR_MEMSLOTS. Then attempt to add one more slot to verify it fails as expected.

Signed-off-by: Wainer dos Santos Moschetta wainersm@redhat.com

tools/testing/selftests/kvm/.gitignore | 1 + tools/testing/selftests/kvm/Makefile | 3 + tools/testing/selftests/kvm/mem_slot_test.c | 85 +++++++++++++++++++++ 3 files changed, 89 insertions(+) create mode 100644 tools/testing/selftests/kvm/mem_slot_test.c

diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore index 16877c3daabf..127d27188427 100644 --- a/tools/testing/selftests/kvm/.gitignore +++ b/tools/testing/selftests/kvm/.gitignore @@ -21,4 +21,5 @@ /demand_paging_test /dirty_log_test /kvm_create_max_vcpus +/mem_slot_test /steal_time diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index 712a2ddd2a27..338b6cdce1a0 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -32,12 +32,14 @@ TEST_GEN_PROGS_x86_64 += clear_dirty_log_test TEST_GEN_PROGS_x86_64 += demand_paging_test TEST_GEN_PROGS_x86_64 += dirty_log_test TEST_GEN_PROGS_x86_64 += kvm_create_max_vcpus +TEST_GEN_PROGS_x86_64 += mem_slot_test TEST_GEN_PROGS_x86_64 += steal_time TEST_GEN_PROGS_aarch64 += clear_dirty_log_test TEST_GEN_PROGS_aarch64 += demand_paging_test TEST_GEN_PROGS_aarch64 += dirty_log_test TEST_GEN_PROGS_aarch64 += kvm_create_max_vcpus +TEST_GEN_PROGS_aarch64 += mem_slot_test TEST_GEN_PROGS_aarch64 += steal_time TEST_GEN_PROGS_s390x = s390x/memop @@ -46,6 +48,7 @@ TEST_GEN_PROGS_s390x += s390x/sync_regs_test TEST_GEN_PROGS_s390x += demand_paging_test TEST_GEN_PROGS_s390x += dirty_log_test TEST_GEN_PROGS_s390x += kvm_create_max_vcpus +TEST_GEN_PROGS_s390x += mem_slot_test TEST_GEN_PROGS += $(TEST_GEN_PROGS_$(UNAME_M)) LIBKVM += $(LIBKVM_$(UNAME_M)) diff --git a/tools/testing/selftests/kvm/mem_slot_test.c b/tools/testing/selftests/kvm/mem_slot_test.c new file mode 100644 index 000000000000..0588dc2e8e01 --- /dev/null +++ b/tools/testing/selftests/kvm/mem_slot_test.c @@ -0,0 +1,85 @@ +// SPDX-License-Identifier: GPL-2.0-only +/*

• • mem_slot_test
• • Copyright (C) 2020, Red Hat, Inc.
• • Test suite for memory region operations.
• */

+#define _GNU_SOURCE /* for program_invocation_short_name */ +#include <linux/kvm.h> +#include <sys/mman.h>

+#include "test_util.h" +#include "kvm_util.h"

+/*

• • Test it can be added memory slots up to KVM_CAP_NR_MEMSLOTS, then any
• • tentative to add further slots should fail.
• */

+static void test_add_max_slots(void) +{

• int ret;
• struct kvm_userspace_memory_region *kvm_region;

nit: this doesn't need to be a pointer, requiring the malloc.

• struct kvm_vm *vm;
• uint32_t max_mem_slots;
• uint32_t mem_reg_flags;
• uint32_t slot;
• uint64_t guest_addr;
• uint64_t mem_reg_npages;
• uint64_t mem_reg_size;
• max_mem_slots = kvm_check_cap(KVM_CAP_NR_MEMSLOTS);
• TEST_ASSERT(max_mem_slots > 0,

•     "KVM_CAP_NR_MEMSLOTS should be greater than 0");
  

• pr_info("Allowed number of memory slots: %i\n", max_mem_slots);
• vm = vm_create(VM_MODE_DEFAULT, 0, O_RDWR);
• /*

• * Uses 1MB sized/aligned memory region since this is the minimal
  

• * required on s390x.
  

• */
  

• mem_reg_size = 0x100000;
• mem_reg_npages = vm_calc_num_guest_pages(VM_MODE_DEFAULT, mem_reg_size);
• mem_reg_flags = 0;

nit: don't really need mem_reg_flags anymore.

• guest_addr = 0x0;
• /* Check it can be added memory slots up to the maximum allowed */
• pr_info("Adding slots 0..%i, each memory region with %ldK size\n",

• (max_mem_slots - 1), mem_reg_size >> 10);
  

• for (slot = 0; slot < max_mem_slots; slot++) {

• vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
  

• 			    guest_addr, slot, mem_reg_npages,
  

• 			    mem_reg_flags);
  

• guest_addr += mem_reg_size;
  

• }
• /* Check it cannot be added memory slots beyond the limit */
• void *mem = mmap(NULL, mem_reg_size, PROT_READ | PROT_WRITE,

• 	 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
  

nit: mem is another middle of block declaration that I didn't notice before

• TEST_ASSERT(mem != MAP_FAILED, "Failed to mmap() host");
• kvm_region = malloc(sizeof(struct kvm_userspace_memory_region));
• TEST_ASSERT(kvm_region,

•     "Failed to malloc() kvm_userspace_memory_region");
  

• kvm_region->slot = slot;
• kvm_region->flags = mem_reg_flags;
• kvm_region->guest_phys_addr = guest_addr;
• kvm_region->userspace_addr = (uint64_t) mem;

You're missing memory_size here, and it's not even guaranteed to be zero, since we malloc'ed and didn't zero initialize.

Actually, I'd probably just drop kvm_region and use a compound literal in the ioctl.

• ret = ioctl(vm_get_fd(vm), KVM_SET_USER_MEMORY_REGION, kvm_region);
• TEST_ASSERT(ret == -1 && errno == EINVAL,

•     "Adding one more memory slot should fail with EINVAL");
  

• munmap(mem, mem_reg_size);
• free(kvm_region);
• kvm_vm_free(vm);

+}

+int main(int argc, char *argv[]) +{

• test_add_max_slots();
• return 0;

+}

2.17.2

Thanks, drew