From nobody Sat Nov 23 12:33:13 2024 Received: from mail-yb1-f202.google.com (mail-yb1-f202.google.com [209.85.219.202]) (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 92430209F2D for ; Wed, 13 Nov 2024 19:02:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731524530; cv=none; b=t9SNo/F6kDwfCBNEX5Y0JXLsrpl+Knm1uw6vDDPul+WqsUk7A8Nkn56BFchq5uiaFlLpCmj+lkDGKIsBRl/gg3AKQvXFpZ/kg6fgJAOe9sErk/to2KZEKvYdVCeW1yT35QTX69NcK9wI0rBKHb2zyr8PYjM5zrqavUGnpOsUoZ8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731524530; c=relaxed/simple; bh=ZbI2dCQ2t6UVu8Y0vsUSVYF43fUxjINBxE2hDpD/UJY=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=egkh2gYENCJJJCao1mE7Lpz6++yAPDiZciQlqPsaVZw/VxwrjgF32veEv61N1jQFn9eXUzvo7uCS8zDUbosz0HchEWfiMFKKCF6BEzX47vKJu89CWz8XI8KE/PCYehDJHeDwKxpTSET0au2QEd0OxmTQMTgQwA3kwHOFbJyEP9E= 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=PZyEkekn; arc=none smtp.client-ip=209.85.219.202 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="PZyEkekn" Received: by mail-yb1-f202.google.com with SMTP id 3f1490d57ef6-e32ff6f578eso1365988276.1 for ; Wed, 13 Nov 2024 11:02:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1731524528; x=1732129328; 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=W3z9O4Nh1QIYeHjkTYeY8Uz2tjDm/EBln1nfLrKHjVI=; b=PZyEkeknSVZoJ2yXDEv+i+eTXxSxrKhwRCmye57m1lE0j6GmuOtsWSbtaIZJ1/lMgR g+6W72kCaul5Dvb1/sWrfTaRVML4jg5WRKMu02aRyI8A5JBk7Mvd3I1EQ9ELWew3KJsT 5wBjlvC4vwaJB+dpLAmE/c3jncPIxd/JxqyMClNsmy6ej9EHzpeNAhTurLjUKUPjxiHP pdsufNYk0DMyBTXSJllyMOB7z8GKYqCILlTXJhFttlKylLPdyfqDFR6szGOtqbpX3sE9 mWrofMZlX5pZxZekvYNviIDiyrTw+GcduWqZoX9AqFMyhhgj7cDY+JuaEkDODpyhEG6V JzTg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1731524528; x=1732129328; 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=W3z9O4Nh1QIYeHjkTYeY8Uz2tjDm/EBln1nfLrKHjVI=; b=GiGhkcClxi13lwMy06Z3BrAJVWys8L76dDcLCfoYR1/UthrElFgQ5I32fypQ6Q4iuW cuLLlWWjaiREFtMo9URvmjplthhD+VQOon51QLUFfgoTbgUBpOTdMrlMhrMGaNWUkGWx c5a4j/W3tSGJWnmqLf9qsZ2ikRftlaT6/xNBUPvW8SJvI1murClkMTFOPQSnHOlG2di2 Uu6TqchdPmheYBmQ2qmpPH22RObEqlpAsAO2uDN7LFCWjYmVTPUltXh6g2LDPy7HUtyi j4BcxYk32CV74pm884kY0HYDPvfS0h+cDwAwMixHJyXGNU9Vk0Qap+fS9C/hF4Gx1DL1 LWFg== X-Forwarded-Encrypted: i=1; AJvYcCU6sdDIiYGjuKTj3wQclC6TTYdy3G5LQDk+sQDNX+P98VocHq50UP1VYkvXPSTpNz5zr5fUdNJFyC3mSD4=@vger.kernel.org X-Gm-Message-State: AOJu0YyCRlPVbYpqNg5dLARj+cydIxFCfGiidpJT22Yqt51sx8dPFXbd 0naz1wdx09eX96SrTn0xw0aUn3XDQ/MBIsXis1N2b+z4Z9zTuVBSnmAdm02D3Gs1d/axhQcUYFL neCAv/DkW5Xm2glqG4+hqRg== X-Google-Smtp-Source: AGHT+IH+p6Jkhv80JbftlyPSva2V+XD4uDlfcpENEqpQ5lUMycdgk8CZBg1V5KJjBNXlSVJn+OptimsRTZOrtvSBNQ== X-Received: from coltonlewis-kvm.c.googlers.com ([fda3:e722:ac3:cc00:11b:3898:ac11:fa18]) (user=coltonlewis job=sendgmr) by 2002:a25:ab07:0:b0:e26:3788:9ea2 with SMTP id 3f1490d57ef6-e380df137cemr10752276.0.1731524527798; Wed, 13 Nov 2024 11:02:07 -0800 (PST) Date: Wed, 13 Nov 2024 19:01:55 +0000 In-Reply-To: <20241113190156.2145593-1-coltonlewis@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20241113190156.2145593-1-coltonlewis@google.com> X-Mailer: git-send-email 2.47.0.338.g60cca15819-goog Message-ID: <20241113190156.2145593-6-coltonlewis@google.com> Subject: [PATCH v8 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-Transfer-Encoding: quoted-printable 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 =3D 0. This way any host-only events with exclude_guest set will never see unexpected guest samples. The behaviour of events with exclude_guest =3D 0 is unchanged. Note that events configured to sample both host and guest may still misattribute a PMI that arrived in the host as a guest event depending on KVM arch and vendor behavior. Signed-off-by: Colton Lewis Acked-by: Mark Rutland Acked-by: Kan Liang Reviewed-by: Oliver Upton --- arch/arm64/include/asm/perf_event.h | 4 ---- arch/arm64/kernel/perf_callchain.c | 28 ---------------------------- arch/x86/events/core.c | 3 --- include/linux/perf_event.h | 21 +++++++++++++++++++-- kernel/events/core.c | 21 +++++++++++++++++---- 5 files changed, 36 insertions(+), 41 deletions(-) diff --git a/arch/arm64/include/asm/perf_event.h b/arch/arm64/include/asm/p= erf_event.h index 31a5584ed4232..ee45b4e773470 100644 --- a/arch/arm64/include/asm/perf_event.h +++ b/arch/arm64/include/asm/perf_event.h @@ -10,10 +10,6 @@ #include =20 #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 =20 diff --git a/arch/arm64/kernel/perf_callchain.c b/arch/arm64/kernel/perf_ca= llchain.c index 01a9d08fc0090..9b7f26b128b51 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_c= tx *entry, =20 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 =3D perf_guest_state(); - int misc =3D 0; - - if (guest_state) { - if (guest_state & PERF_GUEST_USER) - misc |=3D PERF_RECORD_MISC_GUEST_USER; - else - misc |=3D PERF_RECORD_MISC_GUEST_KERNEL; - } else { - if (user_mode(regs)) - misc |=3D PERF_RECORD_MISC_USER; - else - misc |=3D PERF_RECORD_MISC_KERNEL; - } - - return misc; -} diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index bfc0a35fe3993..c75c482d4c52f 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -3005,9 +3005,6 @@ static unsigned long code_segment_base(struct pt_regs= *regs) =20 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); } =20 diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 772ad352856b6..368ea0e9577c7 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1655,8 +1655,9 @@ 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); =20 -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_r= egs *regs); +extern unsigned long perf_instruction_pointer(struct perf_event *event, + struct pt_regs *regs); =20 #ifndef perf_arch_misc_flags # define perf_arch_misc_flags(regs) \ @@ -1667,6 +1668,22 @@ extern unsigned long perf_instruction_pointer(struct= pt_regs *regs); # define perf_arch_bpf_user_pt_regs(regs) regs #endif =20 +#ifndef perf_arch_guest_misc_flags +static inline unsigned long perf_arch_guest_misc_flags(struct pt_regs *reg= s) +{ + unsigned long guest_state =3D perf_guest_state(); + + if (!(guest_state & PERF_GUEST_ACTIVE)) + return 0; + + if (guest_state & PERF_GUEST_USER) + return PERF_RECORD_MISC_GUEST_USER; + else + return PERF_RECORD_MISC_GUEST_KERNEL; +} +# 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 2c44ffd6f4d80..c62164a2ff23a 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7022,13 +7022,26 @@ void perf_unregister_guest_info_callbacks(struct pe= rf_guest_info_callbacks *cbs) EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks); #endif =20 -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); } =20 -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); } =20 @@ -7849,7 +7862,7 @@ void perf_prepare_sample(struct perf_sample_data *dat= a, __perf_event_header__init_id(data, event, filtered_sample_type); =20 if (filtered_sample_type & PERF_SAMPLE_IP) { - data->ip =3D perf_instruction_pointer(regs); + data->ip =3D perf_instruction_pointer(event, regs); data->sample_flags |=3D PERF_SAMPLE_IP; } =20 @@ -8013,7 +8026,7 @@ void perf_prepare_header(struct perf_event_header *he= ader, { header->type =3D PERF_RECORD_SAMPLE; header->size =3D perf_sample_data_size(data, event); - header->misc =3D perf_misc_flags(regs); + header->misc =3D perf_misc_flags(event, regs); =20 /* * If you're adding more sample types here, you likely need to do --=20 2.47.0.338.g60cca15819-goog