From nobody Mon Feb 9 19:30:48 2026 Received: from mail-pj1-f73.google.com (mail-pj1-f73.google.com [209.85.216.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4F5A023237F for ; Fri, 21 Mar 2025 22:15:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742595305; cv=none; b=r0WLUErq6EdAAoOTczfc/gB1R2zPzgUjcpX2prcDBDfnD3Hslf3kaJzbW7LQZV0jQJjuvCas0/OkgBuUjwcxsZi+PDtes4BwBueude6LF8BS7MoBqUJmtc0zQWLLblOzwvz8VBcqMKKxVTn6Yz/EFQMm4ifD7n7EJkokmoKTdSE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742595305; c=relaxed/simple; bh=HHDxIKcmzAzR/uoZwlg+nA4zaO6F0vAAN2EGrZqVmq4=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=SPkMra/XZzOSITgrS7iykE/BJBY6kn14riUCBikXz/Eih6zX3OIOC5XzQevKvE3G0Kq36AMX66qgi0jedhBrZntZCB/p0dGnXhvkBvAQYbLg4kzUPzB4WGdytmJ0U2TKveJI713HzkkP9yw/IAAb29RPnL3453xg6Dk1ejTBuAQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--jmattson.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=d7hDzANb; arc=none smtp.client-ip=209.85.216.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--jmattson.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="d7hDzANb" Received: by mail-pj1-f73.google.com with SMTP id 98e67ed59e1d1-2ff53a4754aso6545950a91.2 for ; Fri, 21 Mar 2025 15:15:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1742595303; x=1743200103; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=a7kZHik3c6W9XM5SaTsdvyDWXohWRJFQwSa2CKHFFJM=; b=d7hDzANbt8arRezwhAyjK8osK91D8cp4EhUQOYICcoej0Kg1406ql+kHhIRls99Y0l hSOtO2Fo28V+ZgeN7WF1VYwNYUzruYYiMrgpwSuv/mv9qexrfRfE/Utzql1bxe031N2Q B/u/BdjCwzPwIpO1mAM4iteIn8sXaUe4fRGOB78cCaMrVrIinGpTP+yhVxa3rWmMVTeg T/gfLfNdatCOcdRljOveiwdlC811kjp/DI50+nzC8yU+kjZsaVrVLyUsKPtWC6GUPlCz x+/YL+xUqPmDZD9JNx57OW1i3fLfNCtCKWnWmOUeG3kPHU0D1kfCOSYpfeSBdhkGVcp3 YTvw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1742595303; x=1743200103; 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=a7kZHik3c6W9XM5SaTsdvyDWXohWRJFQwSa2CKHFFJM=; b=cpMFa3NEHQIApjukGZxBwg7EtFq9m4b6bTq5iDtuJygeITFCIt35q1YavxJA0tAl+b eK2tKATY2MFJj81LNqgFuiNOveenUgsfkHX44dV9j45XkVmCxRiXJtRgB4iaDWTtqfzH fFCPuDHEXPdSxe3Ojd8c/HPNn6Gd+buwpJa6QFswyVNvnklVPQpCQGcEekRiK3OL/TpX 401o+IibVrImyLiWYFCeWrXioDbMM1fa2M9YIGut1SgAnP5UOYR4Equx1wle3iZ1oUAC VQjObDhJkLsmOijCRHB2hhWFVGa/hLUFWFylLbPHwQ64D/IeueLg31eygC8VrwAfVEcZ R9iA== X-Gm-Message-State: AOJu0YyWxIutsNBqKDGZlG9BK+LuqOO0LmzLGZETLewsOFvgOWo3eIFD 7Dc/BK0dfbnzSHVWauOWQQGqFC8IYOlYP4yRp9CRKc2buIIcb9+ddAQ0oJ2Dbdhz7CwWqN9Cru8 XchhQ2DeEmUVVop/2bq95TMkTeRq4/2VE0Nc4pm84hIDRloaj7Ial8+dT+AvU/guAgrErIN1rFh 1B4j+o7cvsvkmSekaqjzbhzjaVpb0gGwufs8owgfNhQHmeia3Fdq8= X-Google-Smtp-Source: AGHT+IHAc9WV/hu5vKfs/Lqpx+fbzF9gJxAd87TudVOtNb5Cf1wOb+Y1LfEdkDtW4JdH2YOfbBHbULWFoamBnA== X-Received: from pjbsc2.prod.google.com ([2002:a17:90b:5102:b0:2ff:611c:bae8]) (user=jmattson job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:4a44:b0:2f4:4003:f3d4 with SMTP id 98e67ed59e1d1-3030ff08e4amr6660559a91.30.1742595303545; Fri, 21 Mar 2025 15:15:03 -0700 (PDT) Date: Fri, 21 Mar 2025 15:14:31 -0700 In-Reply-To: <20250321221444.2449974-1-jmattson@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250321221444.2449974-1-jmattson@google.com> X-Mailer: git-send-email 2.49.0.395.g12beb8f557-goog Message-ID: <20250321221444.2449974-3-jmattson@google.com> Subject: [PATCH v3 2/2] KVM: selftests: Test behavior of KVM_X86_DISABLE_EXITS_APERFMPERF From: Jim Mattson To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Sean Christopherson , Paolo Bonzini Cc: Jim Mattson Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" For a VCPU thread pinned to a single LPU, verify that interleaved host and guest reads of IA32_[AM]PERF return strictly increasing values when APERFMPERF exiting is disabled. Signed-off-by: Jim Mattson --- tools/testing/selftests/kvm/Makefile.kvm | 1 + .../selftests/kvm/x86/aperfmperf_test.c | 162 ++++++++++++++++++ 2 files changed, 163 insertions(+) create mode 100644 tools/testing/selftests/kvm/x86/aperfmperf_test.c diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selft= ests/kvm/Makefile.kvm index 4277b983cace..bfee69b33310 100644 --- a/tools/testing/selftests/kvm/Makefile.kvm +++ b/tools/testing/selftests/kvm/Makefile.kvm @@ -116,6 +116,7 @@ TEST_GEN_PROGS_x86 +=3D x86/amx_test TEST_GEN_PROGS_x86 +=3D x86/max_vcpuid_cap_test TEST_GEN_PROGS_x86 +=3D x86/triple_fault_event_test TEST_GEN_PROGS_x86 +=3D x86/recalc_apic_map_test +TEST_GEN_PROGS_x86 +=3D x86/aperfmperf_test TEST_GEN_PROGS_x86 +=3D access_tracking_perf_test TEST_GEN_PROGS_x86 +=3D coalesced_io_test TEST_GEN_PROGS_x86 +=3D demand_paging_test diff --git a/tools/testing/selftests/kvm/x86/aperfmperf_test.c b/tools/test= ing/selftests/kvm/x86/aperfmperf_test.c new file mode 100644 index 000000000000..7473afb7f6fa --- /dev/null +++ b/tools/testing/selftests/kvm/x86/aperfmperf_test.c @@ -0,0 +1,162 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Test for KVM_X86_DISABLE_EXITS_APERFMPERF + * + * Copyright (C) 2025, Google LLC. + * + * Test the ability to disable VM-exits for rdmsr of IA32_APERF and + * IA32_MPERF. When these VM-exits are disabled, reads of these MSRs + * return the host's values. + * + * Note: Requires read access to /dev/cpu//msr to read host MSRs. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "kvm_util.h" +#include "processor.h" +#include "test_util.h" + +#define NUM_ITERATIONS 100 + +static void pin_thread(int cpu) +{ + cpu_set_t cpuset; + int rc; + + CPU_ZERO(&cpuset); + CPU_SET(cpu, &cpuset); + + rc =3D pthread_setaffinity_np(pthread_self(), sizeof(cpuset), &cpuset); + TEST_ASSERT(rc =3D=3D 0, "%s: Can't set thread affinity", __func__); +} + +static int open_dev_msr(int cpu) +{ + char path[PATH_MAX]; + int msr_fd; + + snprintf(path, sizeof(path), "/dev/cpu/%d/msr", cpu); + msr_fd =3D open(path, O_RDONLY); + __TEST_REQUIRE(msr_fd >=3D 0, "Can't open %s for read", path); + + return msr_fd; +} + +static uint64_t read_dev_msr(int msr_fd, uint32_t msr) +{ + uint64_t data; + ssize_t rc; + + rc =3D pread(msr_fd, &data, sizeof(data), msr); + TEST_ASSERT(rc =3D=3D sizeof(data), "Read of MSR 0x%x failed", msr); + + return data; +} + +static void guest_code(void) +{ + int i; + + for (i =3D 0; i < NUM_ITERATIONS; i++) { + uint64_t aperf =3D rdmsr(MSR_IA32_APERF); + uint64_t mperf =3D rdmsr(MSR_IA32_MPERF); + + GUEST_SYNC2(aperf, mperf); + } + + GUEST_DONE(); +} + +static bool kvm_can_disable_aperfmperf_exits(struct kvm_vm *vm) +{ + int flags =3D vm_check_cap(vm, KVM_CAP_X86_DISABLE_EXITS); + + return flags & KVM_X86_DISABLE_EXITS_APERFMPERF; +} + +int main(int argc, char *argv[]) +{ + uint64_t host_aperf_before, host_mperf_before; + int cpu =3D sched_getcpu(); + struct kvm_vcpu *vcpu; + struct kvm_vm *vm; + int msr_fd; + int i; + + pin_thread(cpu); + + msr_fd =3D open_dev_msr(cpu); + + /* + * This test requires a non-standard VM initialization, because + * KVM_ENABLE_CAP cannot be used on a VM file descriptor after + * a VCPU has been created. + */ + vm =3D vm_create(1); + + TEST_REQUIRE(kvm_can_disable_aperfmperf_exits(vm)); + + vm_enable_cap(vm, KVM_CAP_X86_DISABLE_EXITS, + KVM_X86_DISABLE_EXITS_APERFMPERF); + + vcpu =3D vm_vcpu_add(vm, 0, guest_code); + + host_aperf_before =3D read_dev_msr(msr_fd, MSR_IA32_APERF); + host_mperf_before =3D read_dev_msr(msr_fd, MSR_IA32_MPERF); + + for (i =3D 0; i < NUM_ITERATIONS; i++) { + uint64_t host_aperf_after, host_mperf_after; + uint64_t guest_aperf, guest_mperf; + struct ucall uc; + + vcpu_run(vcpu); + TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO); + + switch (get_ucall(vcpu, &uc)) { + case UCALL_DONE: + break; + case UCALL_ABORT: + REPORT_GUEST_ASSERT(uc); + case UCALL_SYNC: + guest_aperf =3D uc.args[0]; + guest_mperf =3D uc.args[1]; + + host_aperf_after =3D read_dev_msr(msr_fd, MSR_IA32_APERF); + host_mperf_after =3D read_dev_msr(msr_fd, MSR_IA32_MPERF); + + TEST_ASSERT(host_aperf_before < guest_aperf, + "APERF: host_before (%lu) >=3D guest (%lu)", + host_aperf_before, guest_aperf); + TEST_ASSERT(guest_aperf < host_aperf_after, + "APERF: guest (%lu) >=3D host_after (%lu)", + guest_aperf, host_aperf_after); + TEST_ASSERT(host_mperf_before < guest_mperf, + "MPERF: host_before (%lu) >=3D guest (%lu)", + host_mperf_before, guest_mperf); + TEST_ASSERT(guest_mperf < host_mperf_after, + "MPERF: guest (%lu) >=3D host_after (%lu)", + guest_mperf, host_mperf_after); + + host_aperf_before =3D host_aperf_after; + host_mperf_before =3D host_mperf_after; + + break; + } + } + + TEST_ASSERT_EQ(i, NUM_ITERATIONS); + + kvm_vm_free(vm); + close(msr_fd); + + return 0; +} --=20 2.49.0.395.g12beb8f557-goog