diff options
| author | Colton Lewis <coltonlewis@google.com> | 2022-11-07 18:22:05 +0000 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2022-11-16 10:09:19 -0800 |
| commit | b31f21a7e97eee501db86714868d84377e68e4df (patch) | |
| tree | 35e3a382bde5ef7b5f8e4e7a29866ec6f83ddd36 | |
| parent | d886724ea81c6a4dc5e37d4ee09287a31ab8335e (diff) | |
KVM: selftests: implement random number generator for guest code
Implement random number generator for guest code to randomize parts
of the test, making it less predictable and a more accurate reflection
of reality.
The random number generator chosen is the Park-Miller Linear
Congruential Generator, a fancy name for a basic and well-understood
random number generator entirely sufficient for this purpose.
Signed-off-by: Colton Lewis <coltonlewis@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20221107182208.479157-2-coltonlewis@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
| -rw-r--r-- | tools/testing/selftests/kvm/include/test_util.h | 7 | ||||
| -rw-r--r-- | tools/testing/selftests/kvm/lib/test_util.c | 17 |
2 files changed, 24 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h index 3be98e81189a..80d6416f3012 100644 --- a/tools/testing/selftests/kvm/include/test_util.h +++ b/tools/testing/selftests/kvm/include/test_util.h @@ -77,6 +77,13 @@ struct timespec timespec_sub(struct timespec ts1, struct timespec ts2); struct timespec timespec_elapsed(struct timespec start); struct timespec timespec_div(struct timespec ts, int divisor); +struct guest_random_state { + uint32_t seed; +}; + +struct guest_random_state new_guest_random_state(uint32_t seed); +uint32_t guest_random_u32(struct guest_random_state *state); + enum vm_mem_backing_src_type { VM_MEM_SRC_ANONYMOUS, VM_MEM_SRC_ANONYMOUS_THP, diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c index c2d9c6827779..5c22fa4c2825 100644 --- a/tools/testing/selftests/kvm/lib/test_util.c +++ b/tools/testing/selftests/kvm/lib/test_util.c @@ -18,6 +18,23 @@ #include "test_util.h" /* + * Random number generator that is usable from guest code. This is the + * Park-Miller LCG using standard constants. + */ + +struct guest_random_state new_guest_random_state(uint32_t seed) +{ + struct guest_random_state s = {.seed = seed}; + return s; +} + +uint32_t guest_random_u32(struct guest_random_state *state) +{ + state->seed = (uint64_t)state->seed * 48271 % ((uint32_t)(1 << 31) - 1); + return state->seed; +} + +/* * Parses "[0-9]+[kmgt]?". */ size_t parse_size(const char *size) |