From mboxrd@z Thu Jan 1 00:00:00 1970 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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3D82BC4167B for ; Mon, 27 Nov 2023 09:55:10 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1r7YKC-0006c5-Eq; Mon, 27 Nov 2023 04:54:44 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1r7YK3-0006ai-FX for qemu-devel@nongnu.org; Mon, 27 Nov 2023 04:54:36 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1r7YJx-0003sZ-Vy for qemu-devel@nongnu.org; Mon, 27 Nov 2023 04:54:34 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1701078869; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=cM/r8MzsZGaaTECTb4VwCyR2TWXt7Icsvks5c3ZwKVc=; b=OoowMk50mDn4dS5/k6s9Hw5IpqV4iFUYZApny6yGgypvYfouib8ovg1m+mygt76bfPpQ+M NMFAI/naThK/NihDKDmm2stwkTAO/7TU9+TcLJk+ADAnlcgl/Jp9iJUb39JCextZHw89RY 3wIUppRLePrXFpkwHhRWljXIr51rZxw= Received: from mail-pj1-f72.google.com (mail-pj1-f72.google.com [209.85.216.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-692-2SHnqLRROcC9_4p3ItlYOg-1; Mon, 27 Nov 2023 04:54:24 -0500 X-MC-Unique: 2SHnqLRROcC9_4p3ItlYOg-1 Received: by mail-pj1-f72.google.com with SMTP id 98e67ed59e1d1-28554978db1so1499728a91.1 for ; Mon, 27 Nov 2023 01:54:24 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701078863; x=1701683663; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=cM/r8MzsZGaaTECTb4VwCyR2TWXt7Icsvks5c3ZwKVc=; b=PdA+mK+76mqfAHPMxgcCQaNO/MnBNVbYVeJCEz+Hc+1QlgKtmfoPfhGosdN69P6e0B A5nOGrG8gEL7JA0qNicAVEVproXDDWc0lvqasKfXdXRnDhEgd18LzTrmYQGoSySZWyY6 B6nWWgNya4kThaYGl7VJqrj06u2/gWgyqhz78/uFVr7rGL0nazX6LH4iBYrsFdKagP38 R6gYktVvLzt7517OO2I3qJFcg9Xx0fAQ8zwIRWO1VJjdZre27LU2mduQY2XurCB4Wfbp EHK3jwOl6wlne6eqqYRMknRNy+lJr7eeKtgiKdAomM1FdR/Us5nx1jXv5VBDCOA9KFKq V1BA== X-Gm-Message-State: AOJu0YyjMTAnsCTJSMqi16sGLwIdIhARLia6jJHOZo2Kl59sVnPP1lwC tpoBbmhasItAtMw3p1hjvhxRgtRRcBxwhwPSO8YStoj/Wu9cvYJ9P1+WdAT1TqGFnVVbBUfVLpf WIHAAB7WvtP1B4oM= X-Received: by 2002:a17:903:2308:b0:1ce:2fc1:60ef with SMTP id d8-20020a170903230800b001ce2fc160efmr12497968plh.0.1701078863269; Mon, 27 Nov 2023 01:54:23 -0800 (PST) X-Google-Smtp-Source: AGHT+IFmyQ5vYknKazaiYRzfPMmlTZI4Y2vti37sd7I1XRJvOcAr1efGDRk0xXmMRFKdTQeTAp1jsA== X-Received: by 2002:a17:903:2308:b0:1ce:2fc1:60ef with SMTP id d8-20020a170903230800b001ce2fc160efmr12497955plh.0.1701078862891; Mon, 27 Nov 2023 01:54:22 -0800 (PST) Received: from [10.66.61.39] ([43.228.180.230]) by smtp.gmail.com with ESMTPSA id n17-20020a170902d2d100b001cfcfe3c1e5sm1387402plc.173.2023.11.27.01.54.21 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 27 Nov 2023 01:54:22 -0800 (PST) Message-ID: Date: Mon, 27 Nov 2023 17:54:19 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.15.1 Subject: Re: [PATCH v2] arm/kvm: Enable support for KVM_ARM_VCPU_PMU_V3_FILTER Content-Language: en-US To: Eric Auger , qemu-arm@nongnu.org Cc: Paolo Bonzini , Peter Maydell , kvm@vger.kernel.org, qemu-devel@nongnu.org References: <20231117060838.39723-1-shahuang@redhat.com> From: Shaoqin Huang In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=shahuang@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -55 X-Spam_score: -5.6 X-Spam_bar: ----- X-Spam_report: (-5.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-3.477, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Hi Eric, On 11/25/23 02:24, Eric Auger wrote: > Hi, > > On 11/17/23 07:08, Shaoqin Huang wrote: >> The KVM_ARM_VCPU_PMU_V3_FILTER provide the ability to let the VMM decide >> which PMU events are provided to the guest. Add a new option >> `pmu-filter` as -accel sub-option to set the PMU Event Filtering. >> >> The `pmu-filter` has such format: >> >> pmu-filter="{A,D}:start-end[;{A,D}:start-end...]" >> >> The A means "allow" and D means "deny", start is the first event of the >> range and the end is the last one. The first filter action defines if the whole >> event list is an allow or deny list, if the first filter action is "allow", all >> other events are denied except start-end; if the first filter action is "deny", >> all other events are allowed except start-end. For example: >> >> pmu-filter="A:0x11-0x11;A:0x23-0x3a,D:0x30-0x30" >> >> This will allow event 0x11 (The cycle counter), events 0x23 to 0x3a is >> also allowed except the event 0x30 is denied, and all the other events >> are disallowed. >> >> Here is an real example shows how to use the PMU Event Filtering, when >> we launch a guest by use kvm, add such command line: >> >> # qemu-system-aarch64 \ >> -accel kvm,pmu-filter="D:0x11-0x11" >> >> And then in guest, use the perf to count the cycle: >> >> # perf stat sleep 1 >> >> Performance counter stats for 'sleep 1': >> >> 1.22 msec task-clock # 0.001 CPUs utilized >> 1 context-switches # 820.695 /sec >> 0 cpu-migrations # 0.000 /sec >> 55 page-faults # 45.138 K/sec >> cycles >> 1128954 instructions >> 227031 branches # 186.323 M/sec >> 8686 branch-misses # 3.83% of all branches >> >> 1.002492480 seconds time elapsed >> >> 0.001752000 seconds user >> 0.000000000 seconds sys >> >> As we can see, the cycle counter has been disabled in the guest, but >> other pmu events are still work. >> >> Signed-off-by: Shaoqin Huang >> --- >> v1->v2: >> - Add more description for allow and deny meaning in >> commit message. [Sebastian] >> - Small improvement. [Sebastian] >> >> v1: https://lore.kernel.org/all/20231113081713.153615-1-shahuang@redhat.com/ >> --- >> include/sysemu/kvm_int.h | 1 + >> qemu-options.hx | 16 +++++++++++++ >> target/arm/kvm.c | 22 +++++++++++++++++ >> target/arm/kvm64.c | 51 ++++++++++++++++++++++++++++++++++++++++ >> 4 files changed, 90 insertions(+) >> >> diff --git a/include/sysemu/kvm_int.h b/include/sysemu/kvm_int.h >> index fd846394be..8f4601474f 100644 >> --- a/include/sysemu/kvm_int.h >> +++ b/include/sysemu/kvm_int.h >> @@ -120,6 +120,7 @@ struct KVMState >> uint32_t xen_caps; >> uint16_t xen_gnttab_max_frames; >> uint16_t xen_evtchn_max_pirq; >> + char *kvm_pmu_filter; >> }; >> >> void kvm_memory_listener_register(KVMState *s, KVMMemoryListener *kml, >> diff --git a/qemu-options.hx b/qemu-options.hx >> index 42fd09e4de..dd3518092c 100644 >> --- a/qemu-options.hx >> +++ b/qemu-options.hx >> @@ -187,6 +187,7 @@ DEF("accel", HAS_ARG, QEMU_OPTION_accel, >> " tb-size=n (TCG translation block cache size)\n" >> " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" >> " eager-split-size=n (KVM Eager Page Split chunk size, default 0, disabled. ARM only)\n" >> + " pmu-filter={A,D}:start-end[;...] (KVM PMU Event Filter, default no filter. ARM only)\n" >> " notify-vmexit=run|internal-error|disable,notify-window=n (enable notify VM exit and set notify window, x86 only)\n" >> " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL) >> SRST >> @@ -259,6 +260,21 @@ SRST >> impact on the memory. By default, this feature is disabled >> (eager-split-size=0). >> >> + ``pmu-filter={A,D}:start-end[;...]`` >> + KVM implements pmu event filtering to prevent a guest from being able to >> + sample certain events. It has the following format: >> + >> + pmu-filter="{A,D}:start-end[;{A,D}:start-end...]" >> + >> + The A means "allow" and D means "deny", start if the first event of the >> + range and the end is the last one. For example: >> + >> + pmu-filter="A:0x11-0x11;A:0x23-0x3a,D:0x30-0x30" >> + >> + This will allow event 0x11 (The cycle counter), events 0x23 to 0x3a is >> + also allowed except the event 0x30 is denied, and all the other events >> + are disallowed. >> + >> ``notify-vmexit=run|internal-error|disable,notify-window=n`` >> Enables or disables notify VM exit support on x86 host and specify >> the corresponding notify window to trigger the VM exit if enabled. >> diff --git a/target/arm/kvm.c b/target/arm/kvm.c >> index 7903e2ddde..74796de055 100644 >> --- a/target/arm/kvm.c >> +++ b/target/arm/kvm.c >> @@ -1108,6 +1108,21 @@ static void kvm_arch_set_eager_split_size(Object *obj, Visitor *v, >> s->kvm_eager_split_size = value; >> } >> >> +static char *kvm_arch_get_pmu_filter(Object *obj, Error **errp) >> +{ >> + KVMState *s = KVM_STATE(obj); >> + >> + return g_strdup(s->kvm_pmu_filter); >> +} >> + >> +static void kvm_arch_set_pmu_filter(Object *obj, const char *pmu_filter, >> + Error **errp) >> +{ >> + KVMState *s = KVM_STATE(obj); >> + >> + s->kvm_pmu_filter = g_strdup(pmu_filter); >> +} >> + >> void kvm_arch_accel_class_init(ObjectClass *oc) >> { >> object_class_property_add(oc, "eager-split-size", "size", >> @@ -1116,4 +1131,11 @@ void kvm_arch_accel_class_init(ObjectClass *oc) >> >> object_class_property_set_description(oc, "eager-split-size", >> "Eager Page Split chunk size for hugepages. (default: 0, disabled)"); >> + >> + object_class_property_add_str(oc, "pmu-filter", >> + kvm_arch_get_pmu_filter, >> + kvm_arch_set_pmu_filter); >> + >> + object_class_property_set_description(oc, "pmu-filter", >> + "PMU Event Filtering description for guest pmu. (default: NULL, disabled)"); >> } >> diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c >> index 3c175c93a7..6eac328b48 100644 >> --- a/target/arm/kvm64.c >> +++ b/target/arm/kvm64.c >> @@ -10,6 +10,7 @@ >> */ >> >> #include "qemu/osdep.h" >> +#include >> #include >> #include >> >> @@ -131,6 +132,53 @@ static bool kvm_arm_set_device_attr(CPUState *cs, struct kvm_device_attr *attr, >> return true; >> } >> >> +static void kvm_arm_pmu_filter_init(CPUState *cs) >> +{ >> + static bool pmu_filter_init = false; >> + struct kvm_pmu_event_filter filter; >> + struct kvm_device_attr attr = { >> + .group = KVM_ARM_VCPU_PMU_V3_CTRL, >> + .attr = KVM_ARM_VCPU_PMU_V3_FILTER, >> + .addr = (uint64_t)&filter, >> + }; >> + KVMState *kvm_state = cs->kvm_state; >> + char *tmp; >> + char *str, act; >> + >> + if (!kvm_state->kvm_pmu_filter) >> + return; >> + > usually we check the kernel capability (here KVM_CAP_ARM_PMU_V3) before > doing further actions. It allows you to give an inidication to the user > that the kernel does not allow it. Also you should precise in the doc > that this accel option requires host kernel caps I think. I get it. >> + /* This only needs to be called for 1 vcpu. */ >> + if (!pmu_filter_init) >> + pmu_filter_init = true; >> + >> + tmp = g_strdup(kvm_state->kvm_pmu_filter); >> + >> + for (str = strtok(tmp, ";"); str != NULL; str = strtok(NULL, ";")) { >> + unsigned short start = 0, end = 0; >> + >> + sscanf(str, "%c:%hx-%hx", &act, &start, &end); >> + if ((act != 'A' && act != 'D') || (!start && !end)) { >> + error_report("skipping invalid filter %s\n", str); >> + continue; >> + } >> + >> + filter = (struct kvm_pmu_event_filter) { >> + .base_event = start, >> + .nevents = end - start + 1, >> + .action = act == 'A' ? KVM_PMU_EVENT_ALLOW : >> + KVM_PMU_EVENT_DENY, >> + }; >> + >> + if (!kvm_arm_set_device_attr(cs, &attr, "PMU Event Filter")) { >> + error_report("Failed to init PMU Event Filter\n"); > if you do the above, here you know that the host allows to set filters > but that the user input is incorrect. I see. Thanks for your additional information. Thanks, Shaoqin > > Thanks > > Eric >> + abort(); >> + } >> + } >> + >> + g_free(tmp); >> +} >> + >> void kvm_arm_pmu_init(CPUState *cs) >> { >> struct kvm_device_attr attr = { >> @@ -141,6 +189,9 @@ void kvm_arm_pmu_init(CPUState *cs) >> if (!ARM_CPU(cs)->has_pmu) { >> return; >> } >> + >> + kvm_arm_pmu_filter_init(cs); >> + >> if (!kvm_arm_set_device_attr(cs, &attr, "PMU")) { >> error_report("failed to init PMU"); >> abort(); > -- Shaoqin