From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f202.google.com (mail-pl1-f202.google.com [209.85.214.202]) (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 4AA872C15B7 for ; Wed, 6 Aug 2025 19:57:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754510264; cv=none; b=GzydMrySnpKzH9J6uLPFb0XdAJcvnl8y3jj2/IlMxC0K/vu9/vKUG5o2l7duZTJIwpM0TDmPOgD5f8LYCQu6vD9czribhN7tYBw0qqDQP+JgHsnKc9Dem1KOUCNDPxfpNJB2sFbeB4UUH8z4fUljv6eTNMFMr4o1InUbqIRNrdE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754510264; c=relaxed/simple; bh=p9dwRoIkAdNKqXS3ork0V3QcmE8t7/wykyfY7BDBXjw=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=t+106IzmoNeyjsy1pvKIWNg8rYBE/jhUNp5yoEBjDGjIf26OAaKRyL9JwJN6cXbzfqBV6vszyd3+1mBZsr342bPaJFmcJbSHqvcFSTTl/QXGbVDQVsmKsuJNDlwzO1LcfoE5HcMz0miLMFvGThJwBqUbR7rxY9aK6/DxrRQXTnI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=i8IBTCHs; arc=none smtp.client-ip=209.85.214.202 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--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="i8IBTCHs" Received: by mail-pl1-f202.google.com with SMTP id d9443c01a7336-2403e4c82ddso1466315ad.1 for ; Wed, 06 Aug 2025 12:57:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1754510261; x=1755115061; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=1cgAGvW2Sa5tNwASy1Md3TT+4FZc1wpWNQfNLgFp1cE=; b=i8IBTCHsEt2DrcIcxVFbp7SFIHxRMBVKZRXNlv/Q/OQyKdNwpIdP2db8o7nwlILQTK QuBOlCA7EPm3sQ6zh+Ss1qlwCp5NrB9BPwMNlIRBQrUQSQ9ioC3tM1VaKbcXHyk6snqd hmXG7JGUCTvbHS6fpouMnHMYIHSPsl/9lmsPqc9U5Pft9REnjvnuhXAs/kVIzTydoauk ol6Gl5XL9veybgYrnhyj9jS/RgHO4kUfNU2+bp0KYPkkERRQ1/BWcXGfPWwVi9wjT41J QDtvF4djT+6eu1kP6aR7CzKHhr57d0b1TfkAMPhHLqV14Umg+NWAmNN/XmLEPeyXN8Un 2pNA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1754510261; x=1755115061; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=1cgAGvW2Sa5tNwASy1Md3TT+4FZc1wpWNQfNLgFp1cE=; b=nNVbAA0vJ8SPjyvO0FdcmU6dhJ47sdtNWRCy0noOw983nj9kchaZcM7N79xDY3DtY3 +cWo+YbRt2QIh6WmN56rjLFse5vNI6Vc+huKM2tMNhGe1OpIwB7Ol2RlNLcPE7xjB055 mgDbyu+L5c/HPtzY7kN6jgV4gU4pj6q5W6vV8d9sHsLoQNf6iAcP+BfTmIacgG03cmVT MwJCU2bHNiW34CBKNnStbqiVrpyFSVjXIUgfUYlSs7AJLJPGSDayiq6Lz7ZY7Wq3YOp3 Sefw3Gi5y43N9stVWJHXm1jrKHD+VmXOCALX2GiC5m0pbJ+0VFJXb0/u6RY9HiOiuP8Z enHQ== X-Forwarded-Encrypted: i=1; AJvYcCWKddqGgYvbwBaSuwglcRizvkn+FY8xdzHzUeDI+14a+NTu1eutMBf1Hjtn2lqMpnoAaOF+ncoLpqZCR/aMTSYE@vger.kernel.org X-Gm-Message-State: AOJu0YyWGAvQpYiTiuo5OhcZFmBcCslmgdzIJ2C8+DAAPARFUDeJVNVD Vn5MFIa4cGErZGFpmoV0YwUyC4SCmimBi7lO6BASNi12YfvbmLBTk92m6/aEHkiUtiVxhA8nO/j z4WILPQ== X-Google-Smtp-Source: AGHT+IEQshj25YWfgh8jlPDalwm585npWoyFxUPXBG4oqUn1ilItXjqTi+CTUz913BcUQcsY19RFz/4rdM8= X-Received: from plrj9.prod.google.com ([2002:a17:903:289:b0:242:abd5:b3bf]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:c405:b0:240:b879:fed2 with SMTP id d9443c01a7336-2429f55daaamr65961135ad.16.1754510261485; Wed, 06 Aug 2025 12:57:41 -0700 (PDT) Reply-To: Sean Christopherson Date: Wed, 6 Aug 2025 12:56:29 -0700 In-Reply-To: <20250806195706.1650976-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250806195706.1650976-1-seanjc@google.com> X-Mailer: git-send-email 2.50.1.565.gc32cd1483b-goog Message-ID: <20250806195706.1650976-8-seanjc@google.com> Subject: [PATCH v5 07/44] perf: Add APIs to load/put guest mediated PMU context From: Sean Christopherson To: Marc Zyngier , Oliver Upton , Tianrui Zhao , Bibo Mao , Huacai Chen , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Xin Li , "H. Peter Anvin" , Andy Lutomirski , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Sean Christopherson , Paolo Bonzini Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, kvm@vger.kernel.org, loongarch@lists.linux.dev, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Kan Liang , Yongwei Ma , Mingwei Zhang , Xiong Zhang , Sandipan Das , Dapeng Mi Content-Type: text/plain; charset="UTF-8" From: Kan Liang Add exported APIs to load/put a guest mediated PMU context. KVM will load the guest PMU shortly before VM-Enter, and put the guest PMU shortly after VM-Exit. On the perf side of things, schedule out all exclude_guest events when the guest context is loaded, and schedule them back in when the guest context is put. I.e. yield the hardware PMU resources to the guest, by way of KVM. Note, perf is only responsible for managing host context. KVM is responsible for loading/storing guest state to/from hardware. Suggested-by: Sean Christopherson Signed-off-by: Kan Liang Signed-off-by: Mingwei Zhang [sean: shuffle patches around, write changelog] Signed-off-by: Sean Christopherson --- include/linux/perf_event.h | 2 ++ kernel/events/core.c | 61 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 63 insertions(+) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 0958b6d0a61c..42d019d70b42 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1925,6 +1925,8 @@ extern u64 perf_event_pause(struct perf_event *event, bool reset); #ifdef CONFIG_PERF_GUEST_MEDIATED_PMU int perf_create_mediated_pmu(void); void perf_release_mediated_pmu(void); +void perf_load_guest_context(unsigned long data); +void perf_put_guest_context(void); #endif #else /* !CONFIG_PERF_EVENTS: */ diff --git a/kernel/events/core.c b/kernel/events/core.c index 6875b56ddd6b..77398b1ad4c5 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -469,10 +469,19 @@ static cpumask_var_t perf_online_pkg_mask; static cpumask_var_t perf_online_sys_mask; static struct kmem_cache *perf_event_cache; +#ifdef CONFIG_PERF_GUEST_MEDIATED_PMU +static DEFINE_PER_CPU(bool, guest_ctx_loaded); + +static __always_inline bool is_guest_mediated_pmu_loaded(void) +{ + return __this_cpu_read(guest_ctx_loaded); +} +#else static __always_inline bool is_guest_mediated_pmu_loaded(void) { return false; } +#endif /* * perf event paranoia level: @@ -6379,6 +6388,58 @@ void perf_release_mediated_pmu(void) atomic_dec(&nr_mediated_pmu_vms); } EXPORT_SYMBOL_GPL(perf_release_mediated_pmu); + +/* When loading a guest's mediated PMU, schedule out all exclude_guest events. */ +void perf_load_guest_context(unsigned long data) +{ + struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); + + lockdep_assert_irqs_disabled(); + + guard(perf_ctx_lock)(cpuctx, cpuctx->task_ctx); + + if (WARN_ON_ONCE(__this_cpu_read(guest_ctx_loaded))) + return; + + perf_ctx_disable(&cpuctx->ctx, EVENT_GUEST); + ctx_sched_out(&cpuctx->ctx, NULL, EVENT_GUEST); + if (cpuctx->task_ctx) { + perf_ctx_disable(cpuctx->task_ctx, EVENT_GUEST); + task_ctx_sched_out(cpuctx->task_ctx, NULL, EVENT_GUEST); + } + + perf_ctx_enable(&cpuctx->ctx, EVENT_GUEST); + if (cpuctx->task_ctx) + perf_ctx_enable(cpuctx->task_ctx, EVENT_GUEST); + + __this_cpu_write(guest_ctx_loaded, true); +} +EXPORT_SYMBOL_GPL(perf_load_guest_context); + +void perf_put_guest_context(void) +{ + struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); + + lockdep_assert_irqs_disabled(); + + guard(perf_ctx_lock)(cpuctx, cpuctx->task_ctx); + + if (WARN_ON_ONCE(!__this_cpu_read(guest_ctx_loaded))) + return; + + perf_ctx_disable(&cpuctx->ctx, EVENT_GUEST); + if (cpuctx->task_ctx) + perf_ctx_disable(cpuctx->task_ctx, EVENT_GUEST); + + perf_event_sched_in(cpuctx, cpuctx->task_ctx, NULL, EVENT_GUEST); + + if (cpuctx->task_ctx) + perf_ctx_enable(cpuctx->task_ctx, EVENT_GUEST); + perf_ctx_enable(&cpuctx->ctx, EVENT_GUEST); + + __this_cpu_write(guest_ctx_loaded, false); +} +EXPORT_SYMBOL_GPL(perf_put_guest_context); #else static int mediated_pmu_account_event(struct perf_event *event) { return 0; } static void mediated_pmu_unaccount_event(struct perf_event *event) {} -- 2.50.1.565.gc32cd1483b-goog