From patchwork Thu Oct 7 23:34:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Raghavendra Rao Ananta X-Patchwork-Id: 12543821 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 94DDEC433F5 for ; Thu, 7 Oct 2021 23:36:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 784A561076 for ; Thu, 7 Oct 2021 23:36:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242140AbhJGXiO (ORCPT ); Thu, 7 Oct 2021 19:38:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42592 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242781AbhJGXh4 (ORCPT ); Thu, 7 Oct 2021 19:37:56 -0400 Received: from mail-pg1-x549.google.com (mail-pg1-x549.google.com [IPv6:2607:f8b0:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BF0D4C0613EE for ; Thu, 7 Oct 2021 16:35:23 -0700 (PDT) Received: by mail-pg1-x549.google.com with SMTP id 1-20020a630e41000000b002528846c9f2so579203pgo.12 for ; Thu, 07 Oct 2021 16:35:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=eHWmwL/DdyUes1cHwvQEsD28E8ip/Y4KwKGrDHcA804=; b=GM0m7+E0VNGzbrc5pxJMbf1durKLRA8Y5N0Bzcu2SBWiEps3zwM/BBFF/W+nceQB+q basLN4ax9bOBrjbrNilou1jshsUoqDA/LYJMiS8Z1BfQl/R4im5dytZiUIQbJkY5t+ev xZxu4jLHdqUmWvdQfqR7LIOZ0D9/khwutmcqg1Yps2Px0xTy6qTSyiBlDj06XyCK/HrR xy414nG63WpuaSZUFLLo0dpZvSL8L6HiTdFWroVTEWgithKOD0VXo+6VF+UGAKYSObkC 7rhtqLwweVfip0Is/7LhgtzynhwyIX1a/yuSsaIB3BQ5ZnBkP97E7w5bnKCH+xvTJc73 t6yw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=eHWmwL/DdyUes1cHwvQEsD28E8ip/Y4KwKGrDHcA804=; b=VzgUs//9z09PLwbhERt/n5QiCDQedSLg0sbUKWxJ6hGXvu4yVPmxxPvAINhwQmtOIi DmO3nSKyJUwBLOcDJsKl6ASUAHDoYO2x1yvciUJ3HSKSwBU2E72TijOHLSJc/pPQfTW2 D66DWvSh6t7krxnJl2pMRVoDgNur75DJ7RRbr/NkPiSLQTegVD3nIEwGkBdmbh17GITF OP66gnxwncOcwMQYNppSjZgnYnhF6T9a2Mf9HA1UKcuWAm1+274lIWLQiRzjexresXvD 5EWS/2EGDBUsTe4NUcudYXW288hQ+xlcEdFjEpl9TAqZz5rBI0EwzuOxfMsIwTpQa3Ve qIOw== X-Gm-Message-State: AOAM532i3i+FU0yMOUQNcjH8mgndC/sZO7Rkk2KJN8xSPKGClipjvI4H oEM3KCFmtWMwY0wmNkaK+56RH3VTzua0 X-Google-Smtp-Source: ABdhPJya7wHmSzDAkPeQZPGH6y7bHL4W+57qAOc5GKUf8g8bb6ZIYHwjPwQ0n4Op+YXyw8+5O2zSGlsxvvqz X-Received: from rananta-virt.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:1bcc]) (user=rananta job=sendgmr) by 2002:a17:90a:3ee4:: with SMTP id k91mr179113pjc.1.1633649722638; Thu, 07 Oct 2021 16:35:22 -0700 (PDT) Date: Thu, 7 Oct 2021 23:34:39 +0000 In-Reply-To: <20211007233439.1826892-1-rananta@google.com> Message-Id: <20211007233439.1826892-16-rananta@google.com> Mime-Version: 1.0 References: <20211007233439.1826892-1-rananta@google.com> X-Mailer: git-send-email 2.33.0.882.g93a45727a2-goog Subject: [PATCH v8 15/15] KVM: arm64: selftests: arch_timer: Support vCPU migration From: Raghavendra Rao Ananta To: Paolo Bonzini , Marc Zyngier , Andrew Jones , James Morse , Alexandru Elisei , Suzuki K Poulose Cc: Catalin Marinas , Will Deacon , Peter Shier , Ricardo Koller , Oliver Upton , Reiji Watanabe , Jing Zhang , Raghavendra Rao Anata , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Since the timer stack (hardware and KVM) is per-CPU, there are potential chances for races to occur when the scheduler decides to migrate a vCPU thread to a different physical CPU. Hence, include an option to stress-test this part as well by forcing the vCPUs to migrate across physical CPUs in the system at a particular rate. Originally, the bug for the fix with commit 3134cc8beb69d0d ("KVM: arm64: vgic: Resample HW pending state on deactivation") was discovered using arch_timer test with vCPU migrations and can be easily reproduced. Signed-off-by: Raghavendra Rao Ananta Reviewed-by: Andrew Jones --- .../selftests/kvm/aarch64/arch_timer.c | 115 +++++++++++++++++- 1 file changed, 114 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/kvm/aarch64/arch_timer.c b/tools/testing/selftests/kvm/aarch64/arch_timer.c index 3b6ea6a462f4..bf6a45b0b8dc 100644 --- a/tools/testing/selftests/kvm/aarch64/arch_timer.c +++ b/tools/testing/selftests/kvm/aarch64/arch_timer.c @@ -14,6 +14,8 @@ * * The test provides command-line options to configure the timer's * period (-p), number of vCPUs (-n), and iterations per stage (-i). + * To stress-test the timer stack even more, an option to migrate the + * vCPUs across pCPUs (-m), at a particular rate, is also provided. * * Copyright (c) 2021, Google LLC. */ @@ -24,6 +26,8 @@ #include #include #include +#include +#include #include "kvm_util.h" #include "processor.h" @@ -36,17 +40,20 @@ #define NR_TEST_ITERS_DEF 5 #define TIMER_TEST_PERIOD_MS_DEF 10 #define TIMER_TEST_ERR_MARGIN_US 100 +#define TIMER_TEST_MIGRATION_FREQ_MS 2 struct test_args { int nr_vcpus; int nr_iter; int timer_period_ms; + int migration_freq_ms; }; static struct test_args test_args = { .nr_vcpus = NR_VCPUS_DEF, .nr_iter = NR_TEST_ITERS_DEF, .timer_period_ms = TIMER_TEST_PERIOD_MS_DEF, + .migration_freq_ms = TIMER_TEST_MIGRATION_FREQ_MS, }; #define msecs_to_usecs(msec) ((msec) * 1000LL) @@ -80,6 +87,9 @@ static struct test_vcpu_shared_data vcpu_shared_data[KVM_MAX_VCPUS]; static int vtimer_irq, ptimer_irq; +static unsigned long *vcpu_done_map; +static pthread_mutex_t vcpu_done_map_lock; + static void guest_configure_timer_action(struct test_vcpu_shared_data *shared_data) { @@ -215,6 +225,11 @@ static void *test_vcpu_run(void *arg) vcpu_run(vm, vcpuid); + /* Currently, any exit from guest is an indication of completion */ + pthread_mutex_lock(&vcpu_done_map_lock); + set_bit(vcpuid, vcpu_done_map); + pthread_mutex_unlock(&vcpu_done_map_lock); + switch (get_ucall(vm, vcpuid, &uc)) { case UCALL_SYNC: case UCALL_DONE: @@ -233,9 +248,78 @@ static void *test_vcpu_run(void *arg) return NULL; } +static uint32_t test_get_pcpu(void) +{ + uint32_t pcpu; + unsigned int nproc_conf; + cpu_set_t online_cpuset; + + nproc_conf = get_nprocs_conf(); + sched_getaffinity(0, sizeof(cpu_set_t), &online_cpuset); + + /* Randomly find an available pCPU to place a vCPU on */ + do { + pcpu = rand() % nproc_conf; + } while (!CPU_ISSET(pcpu, &online_cpuset)); + + return pcpu; +} + +static int test_migrate_vcpu(struct test_vcpu *vcpu) +{ + int ret; + cpu_set_t cpuset; + uint32_t new_pcpu = test_get_pcpu(); + + CPU_ZERO(&cpuset); + CPU_SET(new_pcpu, &cpuset); + + pr_debug("Migrating vCPU: %u to pCPU: %u\n", vcpu->vcpuid, new_pcpu); + + ret = pthread_setaffinity_np(vcpu->pt_vcpu_run, + sizeof(cpuset), &cpuset); + + /* Allow the error where the vCPU thread is already finished */ + TEST_ASSERT(ret == 0 || ret == ESRCH, + "Failed to migrate the vCPU:%u to pCPU: %u; ret: %d\n", + vcpu->vcpuid, new_pcpu, ret); + + return ret; +} + +static void *test_vcpu_migration(void *arg) +{ + unsigned int i, n_done; + bool vcpu_done; + + do { + usleep(msecs_to_usecs(test_args.migration_freq_ms)); + + for (n_done = 0, i = 0; i < test_args.nr_vcpus; i++) { + pthread_mutex_lock(&vcpu_done_map_lock); + vcpu_done = test_bit(i, vcpu_done_map); + pthread_mutex_unlock(&vcpu_done_map_lock); + + if (vcpu_done) { + n_done++; + continue; + } + + test_migrate_vcpu(&test_vcpu[i]); + } + } while (test_args.nr_vcpus != n_done); + + return NULL; +} + static void test_run(struct kvm_vm *vm) { int i, ret; + pthread_t pt_vcpu_migration; + + pthread_mutex_init(&vcpu_done_map_lock, NULL); + vcpu_done_map = bitmap_zalloc(test_args.nr_vcpus); + TEST_ASSERT(vcpu_done_map, "Failed to allocate vcpu done bitmap\n"); for (i = 0; i < test_args.nr_vcpus; i++) { ret = pthread_create(&test_vcpu[i].pt_vcpu_run, NULL, @@ -243,8 +327,23 @@ static void test_run(struct kvm_vm *vm) TEST_ASSERT(!ret, "Failed to create vCPU-%d pthread\n", i); } + /* Spawn a thread to control the vCPU migrations */ + if (test_args.migration_freq_ms) { + srand(time(NULL)); + + ret = pthread_create(&pt_vcpu_migration, NULL, + test_vcpu_migration, NULL); + TEST_ASSERT(!ret, "Failed to create the migration pthread\n"); + } + + for (i = 0; i < test_args.nr_vcpus; i++) pthread_join(test_vcpu[i].pt_vcpu_run, NULL); + + if (test_args.migration_freq_ms) + pthread_join(pt_vcpu_migration, NULL); + + bitmap_free(vcpu_done_map); } static void test_init_timer_irq(struct kvm_vm *vm) @@ -301,6 +400,8 @@ static void test_print_help(char *name) NR_TEST_ITERS_DEF); pr_info("\t-p: Periodicity (in ms) of the guest timer (default: %u)\n", TIMER_TEST_PERIOD_MS_DEF); + pr_info("\t-m: Frequency (in ms) of vCPUs to migrate to different pCPU. 0 to turn off (default: %u)\n", + TIMER_TEST_MIGRATION_FREQ_MS); pr_info("\t-h: print this help screen\n"); } @@ -308,7 +409,7 @@ static bool parse_args(int argc, char *argv[]) { int opt; - while ((opt = getopt(argc, argv, "hn:i:p:")) != -1) { + while ((opt = getopt(argc, argv, "hn:i:p:m:")) != -1) { switch (opt) { case 'n': test_args.nr_vcpus = atoi(optarg); @@ -335,6 +436,13 @@ static bool parse_args(int argc, char *argv[]) goto err; } break; + case 'm': + test_args.migration_freq_ms = atoi(optarg); + if (test_args.migration_freq_ms < 0) { + pr_info("0 or positive value needed for -m\n"); + goto err; + } + break; case 'h': default: goto err; @@ -358,6 +466,11 @@ int main(int argc, char *argv[]) if (!parse_args(argc, argv)) exit(KSFT_SKIP); + if (test_args.migration_freq_ms && get_nprocs() < 2) { + print_skip("At least two physical CPUs needed for vCPU migration"); + exit(KSFT_SKIP); + } + vm = test_vm_create(); test_run(vm); kvm_vm_free(vm);