From patchwork Wed Aug 31 08:53:26 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Like Xu X-Patchwork-Id: 12960567 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33611ECAAD1 for ; Wed, 31 Aug 2022 08:54:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231641AbiHaIyE (ORCPT ); Wed, 31 Aug 2022 04:54:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44672 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231459AbiHaIx6 (ORCPT ); Wed, 31 Aug 2022 04:53:58 -0400 Received: from mail-pj1-x1030.google.com (mail-pj1-x1030.google.com [IPv6:2607:f8b0:4864:20::1030]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 23160C9EA1; Wed, 31 Aug 2022 01:53:56 -0700 (PDT) Received: by mail-pj1-x1030.google.com with SMTP id q3so10270468pjg.3; Wed, 31 Aug 2022 01:53:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc; bh=Gcm2IRQTqs+/zd8fZUOqHHTB6+RBczdToyXqQTmBoEc=; b=T18AiWlRi04ewNMzE3Y7uPaapmJYaFVOTjtOepcQ0GfIy5ouQQSw0g+ZIPHNsKtYhY RsaWxlAp8Q5/xOXeU0ivK0iyVuANRJkWGBRbxXoSK2cfYvKxgai8+ygd2x8vGm75Dopa ZlwCRI8vJZAnQv/CHGMXRXyAWp6lscAdj96d0EYXaJR+pvf2/k4TqRJo8422ucv5aEbH 2GxByNR69DVz1HNAL09cPBsaSj/EBF8jFOtJa4ws+20gcQEKqvCymsca8UIykya78gRz eiZuK37lTxQ0VZd+DpDMwvDCmHL5t6zuLUYXH+alak34YSD8T/F5S260KyZzUOW6pKSL J37w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc; bh=Gcm2IRQTqs+/zd8fZUOqHHTB6+RBczdToyXqQTmBoEc=; b=WsKjj9ccdSqJEhXrQGQEGrXNNAj2TB251bpRaZ/1KXoDDun4kOC/JIV4TAF2U5uzoy a5DaaiDuPqdMo1hsrcceLlDu8i929QcUo31hnfQokx1IeTbsE6suHr3QQgM0qAOVI6aD EdPCgJ9T3lIT+bH8uag7E7ai0FXdWIWl04OjgS/2JnxFq3ilw/ZtvpUY4aqqdD+U6t8u ZlHCz03+3oTjkQa2xgQeDjxGJaPbYY1s5KG4aa7yvZLnHNgArR2V8IQPw7GzTxC6bM9l MHmcQi93JY6GutlbZ9Z5j27cssVu5JzF4bgwepU66RX9q8hF+ZjXEJq82FfGQROuUron feZQ== X-Gm-Message-State: ACgBeo3Oo5uJdRFQdv1MZHVQ6nyeWUWxfnckdHwSb4eExrwxY7BSoDIC UEKabedIgEu72Vkx7j2Oyxo= X-Google-Smtp-Source: AA6agR5/UBexJglfYrq5LHFgtkDhtnwSjNhhnXinG0hsWVHNVzgqRw6BCv+0Y1tb/ywYSdA1zWdQsw== X-Received: by 2002:a17:90a:868c:b0:1fd:cfe8:5511 with SMTP id p12-20020a17090a868c00b001fdcfe85511mr2151436pjn.174.1661936035476; Wed, 31 Aug 2022 01:53:55 -0700 (PDT) Received: from localhost.localdomain ([103.7.29.32]) by smtp.gmail.com with ESMTPSA id 26-20020a17090a1a1a00b001fab208523esm868772pjk.3.2022.08.31.01.53.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 31 Aug 2022 01:53:55 -0700 (PDT) From: Like Xu X-Google-Original-From: Like Xu To: Paolo Bonzini , Sean Christopherson Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Wanpeng Li Subject: [PATCH v3 5/7] KVM: x86/pmu: Defer counter emulated overflow via pmc->prev_counter Date: Wed, 31 Aug 2022 16:53:26 +0800 Message-Id: <20220831085328.45489-6-likexu@tencent.com> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20220831085328.45489-1-likexu@tencent.com> References: <20220831085328.45489-1-likexu@tencent.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Like Xu Defer reprogramming counters and handling overflow via KVM_REQ_PMU when incrementing counters. KVM skips emulated WRMSR in the VM-Exit fastpath, the fastpath runs with IRQs disabled, skipping instructions can increment and reprogram counters, reprogramming counters can sleep, and sleeping is disallowed while IRQs are disabled. [*] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:580 [*] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 2981888, name: CPU 15/KVM [*] preempt_count: 1, expected: 0 [*] RCU nest depth: 0, expected: 0 [*] INFO: lockdep is turned off. [*] irq event stamp: 0 [*] hardirqs last enabled at (0): [<0000000000000000>] 0x0 [*] hardirqs last disabled at (0): [] copy_process+0x146a/0x62d0 [*] softirqs last enabled at (0): [] copy_process+0x14a9/0x62d0 [*] softirqs last disabled at (0): [<0000000000000000>] 0x0 [*] Preemption disabled at: [*] [] vcpu_enter_guest+0x1001/0x3dc0 [kvm] [*] CPU: 17 PID: 2981888 Comm: CPU 15/KVM Kdump: 5.19.0-rc1-g239111db364c-dirty #2 [*] Call Trace: [*] [*] dump_stack_lvl+0x6c/0x9b [*] __might_resched.cold+0x22e/0x297 [*] __mutex_lock+0xc0/0x23b0 [*] perf_event_ctx_lock_nested+0x18f/0x340 [*] perf_event_pause+0x1a/0x110 [*] reprogram_counter+0x2af/0x1490 [kvm] [*] kvm_pmu_trigger_event+0x429/0x950 [kvm] [*] kvm_skip_emulated_instruction+0x48/0x90 [kvm] [*] handle_fastpath_set_msr_irqoff+0x349/0x3b0 [kvm] [*] vmx_vcpu_run+0x268e/0x3b80 [kvm_intel] [*] vcpu_enter_guest+0x1d22/0x3dc0 [kvm] Add a field to kvm_pmc to track the previous counter value in order to defer overflow detection to kvm_pmu_handle_event() (reprogramming must be done before handling overflow). Opportunistically shrink sizeof(struct kvm_pmc) a bit. Suggested-by: Wanpeng Li Fixes: 9cd803d496e7 ("KVM: x86: Update vPMCs when retiring instructions") Signed-off-by: Like Xu --- arch/x86/include/asm/kvm_host.h | 5 +++-- arch/x86/kvm/pmu.c | 13 ++++++------- arch/x86/kvm/svm/pmu.c | 2 +- arch/x86/kvm/vmx/pmu_intel.c | 4 ++-- 4 files changed, 12 insertions(+), 12 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 4e568a7ef464..08c3f90b4ac3 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -488,7 +488,10 @@ enum pmc_type { struct kvm_pmc { enum pmc_type type; u8 idx; + bool is_paused; + bool intr; u64 counter; + u64 prev_counter; u64 eventsel; struct perf_event *perf_event; struct kvm_vcpu *vcpu; @@ -498,8 +501,6 @@ struct kvm_pmc { * ctrl value for fixed counters. */ u64 current_config; - bool is_paused; - bool intr; }; #define KVM_PMC_MAX_FIXED 3 diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index 7f391750ebd3..3c42df3a55ff 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -349,6 +349,10 @@ void kvm_pmu_handle_event(struct kvm_vcpu *vcpu) } reprogram_counter(pmc); + + if (pmc->counter < pmc->prev_counter) + __kvm_perf_overflow(pmc, false); + pmc->prev_counter = 0; } /* @@ -521,14 +525,9 @@ void kvm_pmu_destroy(struct kvm_vcpu *vcpu) static void kvm_pmu_incr_counter(struct kvm_pmc *pmc) { - u64 prev_count; - - prev_count = pmc->counter; + pmc->prev_counter = pmc->counter; pmc->counter = (pmc->counter + 1) & pmc_bitmask(pmc); - - reprogram_counter(pmc); - if (pmc->counter < prev_count) - __kvm_perf_overflow(pmc, false); + kvm_pmu_request_counter_reprogam(pmc); } static inline bool eventsel_match_perf_hw_id(struct kvm_pmc *pmc, diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c index 70219c19b872..0166f3bc6447 100644 --- a/arch/x86/kvm/svm/pmu.c +++ b/arch/x86/kvm/svm/pmu.c @@ -290,7 +290,7 @@ static void amd_pmu_reset(struct kvm_vcpu *vcpu) struct kvm_pmc *pmc = &pmu->gp_counters[i]; pmc_stop_counter(pmc); - pmc->counter = pmc->eventsel = 0; + pmc->counter = pmc->prev_counter = pmc->eventsel = 0; } } diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index 863a6ff9e214..1d3d0bd3e0e7 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -647,14 +647,14 @@ static void intel_pmu_reset(struct kvm_vcpu *vcpu) pmc = &pmu->gp_counters[i]; pmc_stop_counter(pmc); - pmc->counter = pmc->eventsel = 0; + pmc->counter = pmc->prev_counter = pmc->eventsel = 0; } for (i = 0; i < KVM_PMC_MAX_FIXED; i++) { pmc = &pmu->fixed_counters[i]; pmc_stop_counter(pmc); - pmc->counter = 0; + pmc->counter = pmc->prev_counter = 0; } pmu->fixed_ctr_ctrl = pmu->global_ctrl = pmu->global_status = 0;