Add a wrapper script to simplify running the private_mem_conversions_test with a variety of configurations. Manually invoking the test for all supported memory backing source types is tedious.
The script automatically detects the availability of 2MB and 1GB hugepages and builds a list of source types to test. It then iterates through the list, running the test for each type with both a single memslot and multiple memslots. This makes it easier to get comprehensive test coverage across different memory configurations. Use python to be able to issue an ioctl to /dev/kvm. Update .gitignore to allowlist python scripts. Signed-off-by: Ackerley Tng <[email protected]> --- tools/testing/selftests/kvm/.gitignore | 1 + .../kvm/x86/private_mem_conversions_test.py | 159 ++++++++++++++++++ 2 files changed, 160 insertions(+) create mode 100755 tools/testing/selftests/kvm/x86/private_mem_conversions_test.py diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore index 1d41a046a7bfd..d7e9c1d97e376 100644 --- a/tools/testing/selftests/kvm/.gitignore +++ b/tools/testing/selftests/kvm/.gitignore @@ -4,6 +4,7 @@ !*.c !*.h !*.S +!*.py !*.sh !.gitignore !config diff --git a/tools/testing/selftests/kvm/x86/private_mem_conversions_test.py b/tools/testing/selftests/kvm/x86/private_mem_conversions_test.py new file mode 100755 index 0000000000000..32421ae824d64 --- /dev/null +++ b/tools/testing/selftests/kvm/x86/private_mem_conversions_test.py @@ -0,0 +1,159 @@ +#!/usr/bin/env python3 +# SPDX-License-Identifier: GPL-2.0-only +# +# Wrapper script which runs different test setups of +# private_mem_conversions_test. +# +# Copyright (C) 2025, Google LLC. + +import os +import fcntl +import sys +import subprocess + + +NUM_VCPUS_TO_TEST = 4 +NUM_MEMSLOTS_TO_TEST = NUM_VCPUS_TO_TEST + +# Required pages are based on the test setup in the C code. +# These static requirements are set to the maximum required for +# NUM_VCPUS_TO_TEST, over all the hugetlb-related tests +REQUIRED_NUM_2M_HUGEPAGES = 1024 * NUM_VCPUS_TO_TEST +REQUIRED_NUM_1G_HUGEPAGES = 2 * NUM_VCPUS_TO_TEST + + +def get_hugepage_count(page_size_kb: int) -> int: + """Reads the current number of hugepages available for a given size.""" + try: + path = f"/sys/kernel/mm/hugepages/hugepages-{page_size_kb}kB/nr_hugepages" + with open(path, 'r') as f: + return int(f.read().strip()) + except (FileNotFoundError, ValueError): + return 0 + + +def get_default_hugepage_size_in_kb(): + """Reads the default hugepage size from /proc/meminfo.""" + try: + with open("/proc/meminfo", 'r') as f: + for line in f: + if line.startswith("Hugepagesize:"): + parts = line.split() + if len(parts) >= 2 and parts[1].isdigit(): + return int(parts[1]) + except FileNotFoundError: + return None + + +def run_tests(executable_path: str, src_type: str, num_memslots: int, num_vcpus: int) -> None: + """Runs the test executable with different arguments.""" + print(f"Running tests for backing source type: {src_type}") + + command1 = [executable_path, "-s", src_type, "-m", str(num_memslots)] + print(" ".join(command1)) + _ = subprocess.run(command1, check=True) + + command2 = [executable_path, "-s", src_type, "-m", str(num_memslots), "-n", str(num_vcpus)] + print(" ".join(command2)) + _ = subprocess.run(command2, check=True) + + +def kvm_check_cap(capability: int) -> int: + KVM_CHECK_EXTENSION = 0xAE03 + KVM_DEVICE = '/dev/kvm' + + if not os.path.exists(KVM_DEVICE): + print(f"Error: KVM device not found at {KVM_DEVICE}. Is the 'kvm' module loaded?") + return -1 + + try: + fd = os.open(KVM_DEVICE, os.O_RDWR) + + # Issue the ioctl: fcntl.ioctl(fd, request, arg) + # request is KVM_CHECK_EXTENSION (0xAE03) + # arg is the capability constant (e.g., KVM_CAP_COALESCED_MMIO) + result = fcntl.ioctl(fd, KVM_CHECK_EXTENSION, capability) + + os.close(fd) + return result + except OSError as e: + print(f"Error issuing KVM ioctl on {KVM_DEVICE}: {e}", file=sys.stderr) + if fd > 0: + os.close(fd) + return -1 + + +def kvm_has_gmem_attributes() -> bool: + KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES = 245 + + return kvm_check_cap(KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES) > 0 + + +def get_backing_source_types() -> list[str]: + hugepage_2mb_count = get_hugepage_count(2048) + hugepage_2mb_enabled = hugepage_2mb_count >= REQUIRED_NUM_2M_HUGEPAGES + hugepage_1gb_count = get_hugepage_count(1048576) + hugepage_1gb_enabled = hugepage_1gb_count >= REQUIRED_NUM_1G_HUGEPAGES + + default_hugepage_size_kb = get_default_hugepage_size_in_kb() + hugepage_default_enabled = False + if default_hugepage_size_kb == 2048: + hugepage_default_enabled = hugepage_2mb_enabled + elif default_hugepage_size_kb == 1048576: + hugepage_default_enabled = hugepage_1gb_enabled + + backing_src_types: list[str] = ["anonymous", "anonymous_thp"] + + if hugepage_default_enabled: + backing_src_types.append("anonymous_hugetlb") + else: + print("skipping anonymous_hugetlb backing source type") + + if hugepage_2mb_enabled: + backing_src_types.append("anonymous_hugetlb_2mb") + else: + print("skipping anonymous_hugetlb_2mb backing source type") + + if hugepage_1gb_enabled: + backing_src_types.append("anonymous_hugetlb_1gb") + else: + print("skipping anonymous_hugetlb_1gb backing source type") + + backing_src_types.append("shmem") + + if hugepage_default_enabled: + backing_src_types.append("shared_hugetlb") + else: + print("skipping shared_hugetlb backing source type") + + return backing_src_types + + +def main(): + script_dir = os.path.dirname(os.path.abspath(__file__)) + test_executable = os.path.join(script_dir, "private_mem_conversions_test") + + if not os.path.exists(test_executable): + print(f"Error: Test executable not found at '{test_executable}'", file=sys.stderr) + sys.exit(1) + + return_code = 0 + + backing_src_types = ["shmem"] if kvm_has_gmem_attributes() else get_backing_source_types() + try: + for i, src_type in enumerate(backing_src_types): + if i > 0: + print() + run_tests(test_executable, src_type, NUM_MEMSLOTS_TO_TEST, NUM_VCPUS_TO_TEST) + except subprocess.CalledProcessError as e: + print(f"Test failed for source type '{src_type}'. Command: {' '.join(e.cmd)}", file=sys.stderr) + return_code = e.returncode + except Exception as e: + print(f"An unexpected error occurred: {e}", file=sys.stderr) + return_code = 1 + + sys.exit(return_code) + + +if __name__ == "__main__": + main() -- 2.51.0.858.gf9c4a03a3a-goog
