From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yw1-f202.google.com (mail-yw1-f202.google.com [209.85.128.202]) (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 5A6201BC092 for ; Wed, 11 Sep 2024 22:25:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726093518; cv=none; b=YGHVXhAfV1LytngZmrKG3p1nP3NYQmRvav7M4xpM//oFSCm29fWbMBPkVsIN9RNyA6S8+oDeWo+akliCSQqUipOufh88RfaOdxmP6TfNjyqUsQfSGzdWxdXIYMf1wAAtwa1dfwTYNg1SHtIbLY1u01FkHyjfep46SoTzMi65BFg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726093518; c=relaxed/simple; bh=u9LWUfym3XyKHaJy7fqC/Vhj7o7HAbNr5zui4ChS7LE=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=GZGmrT69+Mm3h/tZMYglWHl+g19c2pjKmBjo8QQmm8XSXxxefaun+BtZd/9uvGLEAk9meun8tPmViIj5jYmtLz+v2MK2M3hSzar0MocKE5ameHlxgdsjjTMf4MQ7F35/l5k0vu0sryBF6csdwmGk6Z+4yroSZ9W6u8snyc1Mm9Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--coltonlewis.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=h3tg2C79; arc=none smtp.client-ip=209.85.128.202 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--coltonlewis.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="h3tg2C79" Received: by mail-yw1-f202.google.com with SMTP id 00721157ae682-69a0536b23aso11805037b3.3 for ; Wed, 11 Sep 2024 15:25:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1726093515; x=1726698315; 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=anqmPTOCFLWtYH4INX466EMjOxNIdwCN/nyhNcnm/nY=; b=h3tg2C79/k5wlX4nWbFINtvN2lcwUR9r3GVeizNYjg2aNWVxB+LKZGHvHCsWPvU7SZ HPURSOJFIYO2tyctPoeQrT/z++FfdCiDD2AFbFaqTdukIDFbNg+diTbzw07zJd8FsWXL OHlsKtURoE41cUD6GpR91vxVg4lPEjz6Xxui6qTqgWQAL2lMiZvGKiw7PdVXhHu3IFjk 2MwQxNpjWyHDLJy2SAX7KAQg4/2gA6DJlOSRAK04itUjWbA3vqh6kAYp/y8wwjn//0VW hrcAv7x1ZHL8r5Z+pJvT3aYPHZY2beKfXN78mBQ9ZDNRqy2ZzQG+Q64QnbZiNNml9sK5 bezA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1726093515; x=1726698315; 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=anqmPTOCFLWtYH4INX466EMjOxNIdwCN/nyhNcnm/nY=; b=SJpAHp+kcp5GL0YYsTrp0k4aX4We0L+Bfm/e+4Vcopor2MKPwUO4qnyW70+Dl5flYx MkwaYETc/L3msAt64BJvu/GfcOu94W00rVBXqWEhGj5m3hRnCR8+u9GzbYi3PALI8T0m utn++eS0tkAtXyiMgdBJnBMubsVQxS3DoVNe1X88KO/jUY9KHYf4RC9M3Hu8MYe2BFj/ Ai4AEXoYhMlIyplcgi246B1Oo3A11oAbf0S3j1PrKljqnpwXzEcJAbWoRwOQERi/KaEG oV8t6uAYMPZqydNWuoL/eTq6pwXaw+m2JDoFfWHmAktQFnuFP3v1n0tZ1Iqrnxpt7bQX C8cQ== X-Forwarded-Encrypted: i=1; AJvYcCUTVIVYG/nLgWShNY3xWhZDTTlMVH7DF3ddlJwkU6K2TYDYeEAvKMP5l7tQybIpnlF4N/dvI+zkUnUm@vger.kernel.org X-Gm-Message-State: AOJu0Yzg6j3umu3w0syqMWfry7pB3zMqKIYGEgjvNsUMAs5Jkv9VcyMd pISU7kHCcQfSTIuK4GhksDqOIXKsAa+blX741skn8OEkf4GlQrbUc4qzEvMLw7BnBU1hqsBvyZZ 6BxUOcUm+kaB8SQTiKSx1Yg== X-Google-Smtp-Source: AGHT+IG/v34+rc6eLaOGVWlOE43Zx45msmHQv1J2ivFD+GxJdG/Q3VFoefy68ei4cpHyCypXn3PaKYm2Ons1cxS0+w== X-Received: from coltonlewis-kvm.c.googlers.com ([fda3:e722:ac3:cc00:11b:3898:ac11:fa18]) (user=coltonlewis job=sendgmr) by 2002:a25:e812:0:b0:e16:51f9:59da with SMTP id 3f1490d57ef6-e1d9dc1b42emr3306276.6.1726093515114; Wed, 11 Sep 2024 15:25:15 -0700 (PDT) Date: Wed, 11 Sep 2024 22:24:32 +0000 In-Reply-To: <20240911222433.3415301-1-coltonlewis@google.com> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240911222433.3415301-1-coltonlewis@google.com> X-Mailer: git-send-email 2.46.0.598.g6f2099f65c-goog Message-ID: <20240911222433.3415301-6-coltonlewis@google.com> Subject: [PATCH v2 5/5] perf: Correct perf sampling with guest VMs From: Colton Lewis To: kvm@vger.kernel.org Cc: Oliver Upton , Sean Christopherson , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , Kan Liang , Will Deacon , Russell King , Catalin Marinas , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Naveen N Rao , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Thomas Gleixner , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, Colton Lewis Content-Type: text/plain; charset="UTF-8" Previously any PMU overflow interrupt that fired while a VCPU was loaded was recorded as a guest event whether it truly was or not. This resulted in nonsense perf recordings that did not honor perf_event_attr.exclude_guest and recorded guest IPs where it should have recorded host IPs. Rework the sampling logic to only record guest samples for events with exclude_guest clear. This way any host-only events with exclude_guest set will never see unexpected guest samples. The behaviour of events with exclude_guest clear is unchanged. Signed-off-by: Colton Lewis --- arch/arm64/include/asm/perf_event.h | 4 ---- arch/arm64/kernel/perf_callchain.c | 28 ---------------------------- arch/x86/events/core.c | 15 ++++----------- include/linux/perf_event.h | 21 +++++++++++++++++++-- kernel/events/core.c | 21 +++++++++++++++++---- 5 files changed, 40 insertions(+), 49 deletions(-) diff --git a/arch/arm64/include/asm/perf_event.h b/arch/arm64/include/asm/perf_event.h index 31a5584ed423..ee45b4e77347 100644 --- a/arch/arm64/include/asm/perf_event.h +++ b/arch/arm64/include/asm/perf_event.h @@ -10,10 +10,6 @@ #include #ifdef CONFIG_PERF_EVENTS -struct pt_regs; -extern unsigned long perf_arch_instruction_pointer(struct pt_regs *regs); -extern unsigned long perf_arch_misc_flags(struct pt_regs *regs); -#define perf_arch_misc_flags(regs) perf_misc_flags(regs) #define perf_arch_bpf_user_pt_regs(regs) ®s->user_regs #endif diff --git a/arch/arm64/kernel/perf_callchain.c b/arch/arm64/kernel/perf_callchain.c index 01a9d08fc009..9b7f26b128b5 100644 --- a/arch/arm64/kernel/perf_callchain.c +++ b/arch/arm64/kernel/perf_callchain.c @@ -38,31 +38,3 @@ void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, arch_stack_walk(callchain_trace, entry, current, regs); } - -unsigned long perf_arch_instruction_pointer(struct pt_regs *regs) -{ - if (perf_guest_state()) - return perf_guest_get_ip(); - - return instruction_pointer(regs); -} - -unsigned long perf_arch_misc_flags(struct pt_regs *regs) -{ - unsigned int guest_state = perf_guest_state(); - int misc = 0; - - if (guest_state) { - if (guest_state & PERF_GUEST_USER) - misc |= PERF_RECORD_MISC_GUEST_USER; - else - misc |= PERF_RECORD_MISC_GUEST_KERNEL; - } else { - if (user_mode(regs)) - misc |= PERF_RECORD_MISC_USER; - else - misc |= PERF_RECORD_MISC_KERNEL; - } - - return misc; -} diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index d51e5d24802b..5f119b9516dc 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -2942,9 +2942,6 @@ static unsigned long code_segment_base(struct pt_regs *regs) unsigned long perf_arch_instruction_pointer(struct pt_regs *regs) { - if (perf_guest_state()) - return perf_guest_get_ip(); - return regs->ip + code_segment_base(regs); } @@ -2974,14 +2971,10 @@ unsigned long perf_arch_misc_flags(struct pt_regs *regs) unsigned int guest_state = perf_guest_state(); unsigned long misc = common_misc_flags(regs); - if (guest_state) { - misc |= perf_arch_guest_misc_flags(regs); - } else { - if (user_mode(regs)) - misc |= PERF_RECORD_MISC_USER; - else - misc |= PERF_RECORD_MISC_KERNEL; - } + if (user_mode(regs)) + misc |= PERF_RECORD_MISC_USER; + else + misc |= PERF_RECORD_MISC_KERNEL; return misc; } diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index d061e327ad54..968f3edd95e4 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1633,8 +1633,9 @@ extern void perf_tp_event(u16 event_type, u64 count, void *record, struct task_struct *task); extern void perf_bp_event(struct perf_event *event, void *data); -extern unsigned long perf_misc_flags(struct pt_regs *regs); -extern unsigned long perf_instruction_pointer(struct pt_regs *regs); +extern unsigned long perf_misc_flags(struct perf_event *event, struct pt_regs *regs); +extern unsigned long perf_instruction_pointer(struct perf_event *event, + struct pt_regs *regs); #ifndef perf_arch_misc_flags # define perf_arch_misc_flags(regs) \ @@ -1645,6 +1646,22 @@ extern unsigned long perf_instruction_pointer(struct pt_regs *regs); # define perf_arch_bpf_user_pt_regs(regs) regs #endif +#ifndef perf_arch_guest_misc_flags +static inline unsigned long perf_arch_guest_misc_flags(struct pt_regs *regs) +{ + unsigned long guest_state = perf_guest_state(); + + if (guest_state & PERF_GUEST_USER) + return PERF_RECORD_MISC_GUEST_USER; + + if (guest_state & PERF_GUEST_ACTIVE) + return PERF_RECORD_MISC_GUEST_KERNEL; + + return 0; +} +# define perf_arch_guest_misc_flags(regs) perf_arch_guest_misc_flags(regs) +#endif + static inline bool has_branch_stack(struct perf_event *event) { return event->attr.sample_type & PERF_SAMPLE_BRANCH_STACK; diff --git a/kernel/events/core.c b/kernel/events/core.c index eeabbf791a8c..c5e57c024d9a 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6921,13 +6921,26 @@ void perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks); #endif -unsigned long perf_misc_flags(struct pt_regs *regs) +static bool should_sample_guest(struct perf_event *event) { + return !event->attr.exclude_guest && perf_guest_state(); +} + +unsigned long perf_misc_flags(struct perf_event *event, + struct pt_regs *regs) +{ + if (should_sample_guest(event)) + return perf_arch_guest_misc_flags(regs); + return perf_arch_misc_flags(regs); } -unsigned long perf_instruction_pointer(struct pt_regs *regs) +unsigned long perf_instruction_pointer(struct perf_event *event, + struct pt_regs *regs) { + if (should_sample_guest(event)) + return perf_guest_get_ip(); + return perf_arch_instruction_pointer(regs); } @@ -7743,7 +7756,7 @@ void perf_prepare_sample(struct perf_sample_data *data, __perf_event_header__init_id(data, event, filtered_sample_type); if (filtered_sample_type & PERF_SAMPLE_IP) { - data->ip = perf_instruction_pointer(regs); + data->ip = perf_instruction_pointer(event, regs); data->sample_flags |= PERF_SAMPLE_IP; } @@ -7907,7 +7920,7 @@ void perf_prepare_header(struct perf_event_header *header, { header->type = PERF_RECORD_SAMPLE; header->size = perf_sample_data_size(data, event); - header->misc = perf_misc_flags(regs); + header->misc = perf_misc_flags(event, regs); /* * If you're adding more sample types here, you likely need to do -- 2.46.0.598.g6f2099f65c-goog