kernel/linux.git/tools/testing/selftests/kvm/kvm_binary_stats_test.c, branch v6.19.11

KVM: selftests: Define wrappers for common syscalls to assert success

2025-10-20T13:30:42+00:00

Add kvm_ wrappers for munmap(), close(), fallocate(), and ftruncate() to cut down on boilerplate code when a sycall is expected to succeed, and to make it easier for developers to remember to assert success. Implement and use a macro framework similar to the kernel's SYSCALL_DEFINE infrastructure to further cut down on boilerplate code, and to drastically reduce the probability of typos as the kernel's syscall definitions can be copy+paste almost verbatim. Provide macros to build the raw () wrappers as well, e.g. to replace hand-coded wrappers (NUMA) or pure open-coded calls. Reviewed-by: Ackerley Tng Tested-by: Ackerley Tng Reviewed-by: Shivank Garg Tested-by: Shivank Garg Link: https://lore.kernel.org/r/20251016172853.52451-7-seanjc@google.com Signed-off-by: Sean Christopherson

KVM: selftests: Define _GNU_SOURCE for all selftests code

2024-04-29T19:49:10+00:00

Define _GNU_SOURCE is the base CFLAGS instead of relying on selftests to manually #define _GNU_SOURCE, which is repetitive and error prone. E.g. kselftest_harness.h requires _GNU_SOURCE for asprintf(), but if a selftest includes kvm_test_harness.h after stdio.h, the include guards result in the effective version of stdio.h consumed by kvm_test_harness.h not defining asprintf(): In file included from x86_64/fix_hypercall_test.c:12: In file included from include/kvm_test_harness.h:11: ../kselftest_harness.h:1169:2: error: call to undeclared function 'asprintf'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 1169 | asprintf(&test_name, "%s%s%s.%s", f->name, | ^ When including the rseq selftest's "library" code, #undef _GNU_SOURCE so that rseq.c controls whether or not it wants to build with _GNU_SOURCE. Reported-by: Muhammad Usama Anjum Acked-by: Claudio Imbrenda Acked-by: Oliver Upton Acked-by: Anup Patel Reviewed-by: Muhammad Usama Anjum Link: https://lore.kernel.org/r/20240423190308.2883084-1-seanjc@google.com Signed-off-by: Sean Christopherson

KVM: selftests: Verify stats fd is usable after VM fd has been closed

2023-07-29T15:05:30+00:00

Verify that VM and vCPU binary stats files are usable even after userspace has put its last direct reference to the VM. This is a regression test for a UAF bug where KVM didn't gift the stats files a reference to the VM. Signed-off-by: Sean Christopherson Message-Id: <20230711230131.648752-8-seanjc@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Verify stats fd can be dup()'d and read

2023-07-29T15:05:30+00:00

Expand the binary stats test to verify that a stats fd can be dup()'d and read, to (very) roughly simulate userspace passing around the file. Adding the dup() test is primarily an intermediate step towards verifying that userspace can read VM/vCPU stats before _and_ after userspace closes its copy of the VM fd; the dup() test itself is only mildly interesting. Signed-off-by: Sean Christopherson Message-Id: <20230711230131.648752-7-seanjc@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Verify userspace can create "redundant" binary stats files

2023-07-29T15:05:30+00:00

Verify that KVM doesn't artificially limit KVM_GET_STATS_FD to a single file per VM/vCPU. There's no known use case for getting multiple stats fds, but it should work, and more importantly creating multiple files will make it easier to test that KVM correct manages VM refcounts for stats files. Signed-off-by: Sean Christopherson Message-Id: <20230711230131.648752-6-seanjc@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Explicitly free vcpus array in binary stats test

2023-07-29T15:05:29+00:00

Explicitly free the all-encompassing vcpus array in the binary stats test so that the test is consistent with respect to freeing all dynamically allocated resources (versus letting them be freed on exit). Signed-off-by: Sean Christopherson Message-Id: <20230711230131.648752-5-seanjc@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Clean up stats fd in common stats_test() helper

2023-07-29T15:05:29+00:00

Move the stats fd cleanup code into stats_test() and drop the superfluous vm_stats_test() and vcpu_stats_test() helpers in order to decouple creation of the stats file from consuming/testing the file (deduping code is a bonus). This will make it easier to test various edge cases related to stats, e.g. that userspace can dup() a stats fd, that userspace can have multiple stats files for a singleVM/vCPU, etc. Signed-off-by: Sean Christopherson Message-Id: <20230711230131.648752-4-seanjc@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Use pread() to read binary stats header

2023-07-29T15:05:28+00:00

Use pread() with an explicit offset when reading the header and the header name for a binary stats fd so that the common helper and the binary stats test don't subtly rely on the file effectively being untouched, e.g. to allow multiple reads of the header, name, etc. Signed-off-by: Sean Christopherson Message-Id: <20230711230131.648752-3-seanjc@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Stop assuming stats are contiguous in kvm_binary_stats_test

2023-01-24T18:06:34+00:00

Remove the assumption from kvm_binary_stats_test that all stats are laid out contiguously in memory. The current stats in KVM are contiguously laid out in memory, but that may change in the future and the ABI specifically allows holes in the stats data (since each stat exposes its own offset). While here drop the check that each stats' offset is less than size_data, as that is now always true by construction. Link: https://lore.kernel.org/kvm/20221208193857.4090582-9-dmatlack@google.com/ Fixes: 0b45d58738cd ("KVM: selftests: Add selftest for KVM statistics data binary interface") Signed-off-by: Jing Zhang [dmatlack: Re-worded the commit message.] Signed-off-by: David Matlack Link: https://lore.kernel.org/r/20230117222707.3949974-1-dmatlack@google.com Signed-off-by: Sean Christopherson

KVM: selftests: Use TAP interface in the kvm_binary_stats_test

2022-12-29T20:33:14+00:00

The kvm_binary_stats_test test currently does not have any output (unless one of the TEST_ASSERT statement fails), so it's hard to say for a user how far it did proceed already. Thus let's make this a little bit more user-friendly and include some TAP output via the kselftest.h interface. Signed-off-by: Thomas Huth Reviewed-by: Andrew Jones Message-Id: <20221004093131.40392-2-thuth@redhat.com> Signed-off-by: Paolo Bonzini