From patchwork Wed Oct 19 22:13:19 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Colton Lewis X-Patchwork-Id: 13012379 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 39D54C4332F for ; Wed, 19 Oct 2022 22:13:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231145AbiJSWNw (ORCPT ); Wed, 19 Oct 2022 18:13:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230253AbiJSWNv (ORCPT ); Wed, 19 Oct 2022 18:13:51 -0400 Received: from mail-io1-xd49.google.com (mail-io1-xd49.google.com [IPv6:2607:f8b0:4864:20::d49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 61EAA48A30 for ; Wed, 19 Oct 2022 15:13:50 -0700 (PDT) Received: by mail-io1-xd49.google.com with SMTP id n23-20020a056602341700b00689fc6dbfd6so14576648ioz.8 for ; Wed, 19 Oct 2022 15:13:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=zHCN1NpOBIjvJ3dOyBokgsfXrMU3XntQ/lV2trTRMnY=; b=AIsEXGNHQkLZcACXCjLRLHw7oAbFXTYbBeqOJgK86yQyNBsZdBjGgkwMxJpMwW9v6I k2xYRrNC6r2Z7rN/8fBisMgGQ0gD2ayzcGpfeLWztaTThcS3RNYS1bNNjuylSsmqN2S1 IZuUv2SGEpxQQCotnFdpUu1K+R+Jev8Y9AC/K7IDJcspV2DHStWcA0ZQo0v0bj7kkwDX iCuGFEQV89hTIvWVhUd13viqOF1Q5kghfcJ0kDsXi5nAO4c/RXhLfzFMG4FQU3u+oaQD DooGaBtN5pJPshkxA1uNA/F5ETYze+qwJUJNhQAS/mR+G35XMTLU2dSGxEm4alMfucMv lPCw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=zHCN1NpOBIjvJ3dOyBokgsfXrMU3XntQ/lV2trTRMnY=; b=UfMDLahPuW+KDu7+WmXcPUaF+ASf7PTSMnPlqYbPJkJeflGkjoNM87IupYH4m4sBO1 kkH493Eqs90+EAOoCSHgbZAydG3kZQs0jazZAHsU29ovfcES9VGo7rmKSJfM1z+4CFWz 2EWN0bKgNTT3IpIUzLgI7dM2rO+0ETo4lQxBfKDkv8yWBFxQLq8qFHDNwlskSwikGIvv wPPiAAAULBW5M3P1kZTqf4eBv8Hb1sSchmF9JvAPT7hjIJRNE6TRXADUYWUlibZyNE6U IIXs4C6CypdqgM8z4asNlHsOvO8kx4dRzT784DaqoJQqRtoIFEbjbpoDy1qrW6LCckrn ZdvA== X-Gm-Message-State: ACrzQf0JH2HsX+S89Qrkf4yeaeKCdwZ7lEKPapcHlTtd0xRxTwx0AiC5 FTbUKXXweFuIKwLbjjeYAo05/8VR3CTjry5/MixxtuUAEp3gT7pA5K4HboX355V2qQ5oqPtK+Cx Js1sRiKNP4lg7xGC85nbQ1nzI12mGSya2UuFmztX3FhrwYuhzlBvFSV3COGmUdramFF21zlk= X-Google-Smtp-Source: AMsMyM5IkMUEqTmtYSOBcyBAbmzwb+lHabB7pE8dcVcKiHudSYY25OINRJBF/cNwmTxCfonAzvMwa9Emlr/grB4r+Q== X-Received: from coltonlewis-kvm.c.googlers.com ([fda3:e722:ac3:cc00:2b:ff92:c0a8:14ce]) (user=coltonlewis job=sendgmr) by 2002:a05:6e02:1054:b0:2fa:a73:cfa1 with SMTP id p20-20020a056e02105400b002fa0a73cfa1mr7717158ilj.203.1666217629728; Wed, 19 Oct 2022 15:13:49 -0700 (PDT) Date: Wed, 19 Oct 2022 22:13:19 +0000 In-Reply-To: <20221019221321.3033920-1-coltonlewis@google.com> Mime-Version: 1.0 References: <20221019221321.3033920-1-coltonlewis@google.com> X-Mailer: git-send-email 2.38.0.413.g74048e4d9e-goog Message-ID: <20221019221321.3033920-2-coltonlewis@google.com> Subject: [PATCH v7 1/3] KVM: selftests: implement random number generation for guest code From: Colton Lewis To: kvm@vger.kernel.org Cc: pbonzini@redhat.com, maz@kernel.org, dmatlack@google.com, seanjc@google.com, oupton@google.com, ricarkol@google.com, Colton Lewis Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Implement random number generation for guest code to randomize parts of the test, making it less predictable and a more accurate reflection of reality. Create a -r argument to specify a random seed. If no argument is provided, the seed defaults to 0. The random seed is set with perf_test_set_random_seed() and must be set before guest_code runs to apply. 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. Each vCPU calculates its own seed by adding its index to the seed provided. Signed-off-by: Colton Lewis Reviewed-by: Ricardo Koller Reviewed-by: David Matlack --- .../testing/selftests/kvm/dirty_log_perf_test.c | 12 ++++++++++-- .../selftests/kvm/include/perf_test_util.h | 2 ++ tools/testing/selftests/kvm/include/test_util.h | 7 +++++++ .../testing/selftests/kvm/lib/perf_test_util.c | 7 +++++++ tools/testing/selftests/kvm/lib/test_util.c | 17 +++++++++++++++++ 5 files changed, 43 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/kvm/dirty_log_perf_test.c b/tools/testing/selftests/kvm/dirty_log_perf_test.c index f99e39a672d3..c97a5e455699 100644 --- a/tools/testing/selftests/kvm/dirty_log_perf_test.c +++ b/tools/testing/selftests/kvm/dirty_log_perf_test.c @@ -132,6 +132,7 @@ struct test_params { bool partition_vcpu_memory_access; enum vm_mem_backing_src_type backing_src; int slots; + uint32_t random_seed; }; static void toggle_dirty_logging(struct kvm_vm *vm, int slots, bool enable) @@ -225,6 +226,9 @@ static void run_test(enum vm_guest_mode mode, void *arg) p->slots, p->backing_src, p->partition_vcpu_memory_access); + /* If no argument provided, random seed will be 1. */ + pr_info("Random seed: %u\n", p->random_seed); + perf_test_set_random_seed(vm, p->random_seed ? p->random_seed : 1); perf_test_set_wr_fract(vm, p->wr_fract); guest_num_pages = (nr_vcpus * guest_percpu_mem_size) >> vm->page_shift; @@ -352,7 +356,7 @@ static void help(char *name) { puts(""); printf("usage: %s [-h] [-i iterations] [-p offset] [-g] " - "[-m mode] [-n] [-b vcpu bytes] [-v vcpus] [-o] [-s mem type]" + "[-m mode] [-n] [-b vcpu bytes] [-v vcpus] [-o] [-r random seed ] [-s mem type]" "[-x memslots]\n", name); puts(""); printf(" -i: specify iteration counts (default: %"PRIu64")\n", @@ -380,6 +384,7 @@ static void help(char *name) printf(" -v: specify the number of vCPUs to run.\n"); printf(" -o: Overlap guest memory accesses instead of partitioning\n" " them into a separate region of memory for each vCPU.\n"); + printf(" -r: specify the starting random seed.\n"); backing_src_help("-s"); printf(" -x: Split the memory region into this number of memslots.\n" " (default: 1)\n"); @@ -406,7 +411,7 @@ int main(int argc, char *argv[]) guest_modes_append_default(); - while ((opt = getopt(argc, argv, "eghi:p:m:nb:f:v:os:x:")) != -1) { + while ((opt = getopt(argc, argv, "eghi:p:m:nb:f:v:or:s:x:")) != -1) { switch (opt) { case 'e': /* 'e' is for evil. */ @@ -442,6 +447,9 @@ int main(int argc, char *argv[]) case 'o': p.partition_vcpu_memory_access = false; break; + case 'r': + p.random_seed = atoi(optarg); + break; case 's': p.backing_src = parse_backing_src_type(optarg); break; diff --git a/tools/testing/selftests/kvm/include/perf_test_util.h b/tools/testing/selftests/kvm/include/perf_test_util.h index eaa88df0555a..f1050fd42d10 100644 --- a/tools/testing/selftests/kvm/include/perf_test_util.h +++ b/tools/testing/selftests/kvm/include/perf_test_util.h @@ -35,6 +35,7 @@ struct perf_test_args { uint64_t gpa; uint64_t size; uint64_t guest_page_size; + uint32_t random_seed; int wr_fract; /* Run vCPUs in L2 instead of L1, if the architecture supports it. */ @@ -52,6 +53,7 @@ struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int nr_vcpus, void perf_test_destroy_vm(struct kvm_vm *vm); void perf_test_set_wr_fract(struct kvm_vm *vm, int wr_fract); +void perf_test_set_random_seed(struct kvm_vm *vm, uint32_t random_seed); void perf_test_start_vcpu_threads(int vcpus, void (*vcpu_fn)(struct perf_test_vcpu_args *)); void perf_test_join_vcpu_threads(int vcpus); diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h index befc754ce9b3..9e4f36a1a8b0 100644 --- a/tools/testing/selftests/kvm/include/test_util.h +++ b/tools/testing/selftests/kvm/include/test_util.h @@ -152,4 +152,11 @@ static inline void *align_ptr_up(void *x, size_t size) return (void *)align_up((unsigned long)x, size); } +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); + #endif /* SELFTEST_KVM_TEST_UTIL_H */ diff --git a/tools/testing/selftests/kvm/lib/perf_test_util.c b/tools/testing/selftests/kvm/lib/perf_test_util.c index 9618b37c66f7..5f0eebb626b5 100644 --- a/tools/testing/selftests/kvm/lib/perf_test_util.c +++ b/tools/testing/selftests/kvm/lib/perf_test_util.c @@ -49,6 +49,7 @@ void perf_test_guest_code(uint32_t vcpu_idx) uint64_t gva; uint64_t pages; int i; + struct guest_random_state rand_state = new_guest_random_state(pta->random_seed + vcpu_idx); gva = vcpu_args->gva; pages = vcpu_args->pages; @@ -229,6 +230,12 @@ void perf_test_set_wr_fract(struct kvm_vm *vm, int wr_fract) sync_global_to_guest(vm, perf_test_args); } +void perf_test_set_random_seed(struct kvm_vm *vm, uint32_t random_seed) +{ + perf_test_args.random_seed = random_seed; + sync_global_to_guest(vm, perf_test_args.random_seed); +} + uint64_t __weak perf_test_nested_pages(int nr_vcpus) { return 0; diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c index 6d23878bbfe1..c4d2749fb2c3 100644 --- a/tools/testing/selftests/kvm/lib/test_util.c +++ b/tools/testing/selftests/kvm/lib/test_util.c @@ -17,6 +17,23 @@ #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]?". */