From nobody Mon Feb 9 06:28:56 2026 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 5D7CCC4332F for ; Fri, 3 Nov 2023 23:05:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231172AbjKCXF6 (ORCPT ); Fri, 3 Nov 2023 19:05:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45130 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231523AbjKCXFu (ORCPT ); Fri, 3 Nov 2023 19:05:50 -0400 Received: from mail-pg1-x54a.google.com (mail-pg1-x54a.google.com [IPv6:2607:f8b0:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2B982D6A for ; Fri, 3 Nov 2023 16:05:48 -0700 (PDT) Received: by mail-pg1-x54a.google.com with SMTP id 41be03b00d2f7-56f75e70190so1799557a12.3 for ; Fri, 03 Nov 2023 16:05:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1699052747; x=1699657547; 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=MBBm7FlqrdtgkBqnXXMbaJMJAl32htix/RXmITDIFAI=; b=gueaNZV7Vxljy9Q/ZB6efChaUm6uV0JEKE+GkSzYs0C+5Hb2jInuMrWqWStXtvCpsj FIV/nOkF+TaLyFtofsUQCUscJw5TWNJNazwdeKTjzT2uXcYc+MX3n3tEFjW7UjyLeDlz Ba8/sno1/y4NA59qibyaIZ+4UY8/vZYJarUESnE6yZqKgb2vf8hyojXbDWS6AHyWhC93 LT/QK7GJu/AenrGm6vl7rj7+wTbnMpLxej/hVdg84XSyGDUmeGfFgJYzFj24pvf086VK lHwNygVS9lQhMIRSH7iRAJk1JVnweIZ0Ct6vhTW1LxUHGPH7mEESHAuQX4PP/BCMZCcU K91Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1699052747; x=1699657547; 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=MBBm7FlqrdtgkBqnXXMbaJMJAl32htix/RXmITDIFAI=; b=Q9oRkGMZ6gPB2ceD6ncjXN0TFmbOXZhGAeRzt+lYK4DxnGQuXpyuLS4aitD+fQp7A0 F9Su2LLPnXujL3tCD2cPGLaT95m6gvXIk4AfR/0wK6VKTRJ9c4h4Qb79qIR2QTHLBKhc kZ8aInBgMM6GoCxCw5wXi0f9zdrJCz1mg5BLz3S8PFbpIvg0txmqgsgGl2Lr2p6PtCno G3c02TJ1Z+LnsUYQc2KcCLFAaP9Lifa3mB8wMKYV5HXa2nG/hf4Sfpot5xLHwbE3Pclh IhtxgTtkUSa7dqXarqzrs/hn9oXC9UexeMhqSTDM5WsIN3ldl9HkoXmEJi70ZbxVvPVH 8sVA== X-Gm-Message-State: AOJu0YwPB4KaDnz3rP7yTt65Eq5otgmfiqb/Xna3UAeTfzXklySRzU2Z yvvGxusUQdStuzwPZwE9zBgBoYC9Ou0= X-Google-Smtp-Source: AGHT+IFxtJq6aoqhiA8nBzG/BJYd7WTpHjuZTRpBVdCBHzeUugR2TSdZ06fuNypYZHlYf/ldSoVRa3HYNVE= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:903:3303:b0:1cc:38e0:dbab with SMTP id jk3-20020a170903330300b001cc38e0dbabmr336922plb.3.1699052747477; Fri, 03 Nov 2023 16:05:47 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 3 Nov 2023 16:05:37 -0700 In-Reply-To: <20231103230541.352265-1-seanjc@google.com> Mime-Version: 1.0 References: <20231103230541.352265-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.869.gea05f2083d-goog Message-ID: <20231103230541.352265-3-seanjc@google.com> Subject: [PATCH v2 2/6] KVM: x86/pmu: Reset the PMU, i.e. stop counters, before refreshing From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Dapeng Mi , Mingwei Zhang , Roman Kagan , Jim Mattson , Like Xu Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Stop all counters and release all perf events before refreshing the vPMU, i.e. before reconfiguring the vPMU to respond to changes in the vCPU model. Clear need_cleanup in kvm_pmu_reset() as well so that KVM doesn't prematurely stop counters, e.g. if KVM enters the guest and enables counters before the vCPU is scheduled out. Cc: stable@vger.kernel.org Reviewed-by: Dapeng Mi Signed-off-by: Sean Christopherson --- arch/x86/kvm/pmu.c | 35 ++++++++++++++++++++++------------- 1 file changed, 22 insertions(+), 13 deletions(-) diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index 027e9c3c2b93..dc8e8e907cfb 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -657,25 +657,14 @@ int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr= _data *msr_info) return 0; } =20 -/* refresh PMU settings. This function generally is called when underlying - * settings are changed (such as changes of PMU CPUID by guest VMs), which - * should rarely happen. - */ -void kvm_pmu_refresh(struct kvm_vcpu *vcpu) -{ - if (KVM_BUG_ON(kvm_vcpu_has_run(vcpu), vcpu->kvm)) - return; - - bitmap_zero(vcpu_to_pmu(vcpu)->all_valid_pmc_idx, X86_PMC_IDX_MAX); - static_call(kvm_x86_pmu_refresh)(vcpu); -} - void kvm_pmu_reset(struct kvm_vcpu *vcpu) { struct kvm_pmu *pmu =3D vcpu_to_pmu(vcpu); struct kvm_pmc *pmc; int i; =20 + pmu->need_cleanup =3D false; + bitmap_zero(pmu->reprogram_pmi, X86_PMC_IDX_MAX); =20 for_each_set_bit(i, pmu->all_valid_pmc_idx, X86_PMC_IDX_MAX) { @@ -695,6 +684,26 @@ void kvm_pmu_reset(struct kvm_vcpu *vcpu) static_call_cond(kvm_x86_pmu_reset)(vcpu); } =20 + +/* + * Refresh the PMU configuration for the vCPU, e.g. if userspace changes C= PUID + * and/or PERF_CAPABILITIES. + */ +void kvm_pmu_refresh(struct kvm_vcpu *vcpu) +{ + if (KVM_BUG_ON(kvm_vcpu_has_run(vcpu), vcpu->kvm)) + return; + + /* + * Stop/release all existing counters/events before realizing the new + * vPMU model. + */ + kvm_pmu_reset(vcpu); + + bitmap_zero(vcpu_to_pmu(vcpu)->all_valid_pmc_idx, X86_PMC_IDX_MAX); + static_call(kvm_x86_pmu_refresh)(vcpu); +} + void kvm_pmu_init(struct kvm_vcpu *vcpu) { struct kvm_pmu *pmu =3D vcpu_to_pmu(vcpu); --=20 2.42.0.869.gea05f2083d-goog