From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f74.google.com (mail-pj1-f74.google.com [209.85.216.74]) (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 4BE238F66 for ; Thu, 15 May 2025 00:41:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747269717; cv=none; b=J5Rqvfn5dhhC5CLOsjpKi1B5yima5ZzXsTiUwTlZ0+DDEnW+uRdPmrjmeynmmsy2Yz36wEzeBwVqpGwqZy0A+11grclB/14Oa4dS7sovjqu6JazMAVplrQBsi4UrCqG8CNqD6cMJAdId4JQ+pZ1M0yrjZlbOXDdXwarRbL1LvNo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747269717; c=relaxed/simple; bh=iFfSERXqavDusfX1VCYEGypsr/UbOLQkpthUgOBORHo=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=nlT04WjUtbUTA0SJx1NJpEBt4j4lIv82A8B8+7syuUpf2CgzdMwY/DuG1QZJqBCSTl4eUkkTcPlCDsLnHkV8dzdAZzASLsAjIEuPRWrbNhQHs5gRiFoVW6Dx3F8AI4y3uIqFN1ty61cX6f8bVyFMEyV2IFwUoxxhgswHr0c/NNo= 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=u1ISadiA; arc=none smtp.client-ip=209.85.216.74 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="u1ISadiA" Received: by mail-pj1-f74.google.com with SMTP id 98e67ed59e1d1-30ac9abbd4bso651592a91.3 for ; Wed, 14 May 2025 17:41:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1747269715; x=1747874515; 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=ip9lVrq9USVSeXSDB7Ry76GsvvsCyjvJx3E1UJmIZxg=; b=u1ISadiAZpAaCftabQ06ASHhPH/NGcJx2PrPazkovU5v0dj+iy3oYUZ7KNLNDXrRee YodszaCJgd/yLiNRsG2eyN/c3ndUs5TyavEBUR6Jo4vMwES8nZTTC43qx/bhA2uFuLCz 2Vlj89TejxcoL4ygvleWDkLXw4DQ1VgQC1TldwB735MiDa69qXFXjFRoB/xENsfA1j9F 6VtXi6jCjOLCArZ5p34VYOSZ9IBZhp+/ntLMNm11cuZztYJ1X89D5wW3oSoJWfiX5SIA o99DFrnmKDNzG6QRGZTpk7H86vQ9d5Le40+LbPc6a5q6TGSUKr8j9juFNsiTio8yFD4i kpYw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1747269715; x=1747874515; 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=ip9lVrq9USVSeXSDB7Ry76GsvvsCyjvJx3E1UJmIZxg=; b=u/5FsJ5lJ7UPDaBuZ9NMbAwX/riIGW9v2ZfC4p0+YIc6tmw2MXDkgepghWg1rbGvnJ sJzjTP2GVPf0C+pZ6X7FaOPP1YZfqU88TNqwcEjBS8simtpKobuhZpDNt6ooPhhS4+4X zrM0ZsFuAHa031c91LBjOUqrqd/zadp8wmT4wNBh8yFdrQgaEadWgreQIYbS+exG1jzN OthWS6mf1rSt00cH+U9L5TdQZV91QA3QZeYYF7Xy7fPqmp2GjVcBfNlZp0O2D9wWoaTh IE1y3TSPoVwBHpPPah6EgJkQm4yueyMnSKzFptiOvkZhqB0pLJ1H0oI+W3bEWe7CO+wL BRtA== X-Forwarded-Encrypted: i=1; AJvYcCWHQ2Xb//c7Gp9PwPv8JGQZk7ixMdsWEerbMcyWl7H+/FhBjJJpglzWVbiMQ+hDLlN578OkSbrPcRyzqTYiNl/j@vger.kernel.org X-Gm-Message-State: AOJu0YxXS1Mkmd4JbmIs2W47ziRoX2i+ydt3jhljg3dmCEdB4ZSceuFS ZHpAkrTzqbIZWNOwafXf4re5oByLEx0PT8YvjSILC4kIaEHyDIFvGKO9gysA47i+a+0qN5+VuT0 n9w== X-Google-Smtp-Source: AGHT+IEQQ2m9ChwSAgqTmcRTO2wVdgVG7h1KF3HTjNgQHsWD0J4xMyzMFU8Gl88ps+nHWYhsRW6yQlC7s94= X-Received: from pjboe15.prod.google.com ([2002:a17:90b:394f:b0:2ef:7af4:5e8e]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:55c7:b0:30c:5604:f646 with SMTP id 98e67ed59e1d1-30e519309bfmr943173a91.25.1747269715611; Wed, 14 May 2025 17:41:55 -0700 (PDT) Date: Wed, 14 May 2025 17:41:54 -0700 In-Reply-To: <20250324173121.1275209-24-mizhang@google.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250324173121.1275209-1-mizhang@google.com> <20250324173121.1275209-24-mizhang@google.com> Message-ID: Subject: Re: [PATCH v4 23/38] KVM: x86/pmu: Configure the interception of PMU MSRs From: Sean Christopherson To: Mingwei Zhang Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Paolo Bonzini , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , Liang@google.com, Kan , "H. Peter Anvin" , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, Yongwei Ma , Xiong Zhang , Dapeng Mi , Jim Mattson , Sandipan Das , Zide Chen , Eranian Stephane , Shukla Manali , Nikunj Dadhania Content-Type: text/plain; charset="us-ascii" Again, use more precise language. "Configure interceptions" is akin to "do work". It gives readers a vague idea of what's going on, but this KVM: x86/pmu: Disable interception of select PMU MSRs for mediated vPMUs is just as concise, and more descriptive. > + /* > + * In mediated vPMU, intercept global PMU MSRs when guest PMU only owns > + * a subset of counters provided in HW or its version is less than 2. > + */ > + if (kvm_mediated_pmu_enabled(vcpu) && kvm_pmu_has_perf_global_ctrl(pmu) && > + pmu->nr_arch_gp_counters == kvm_pmu_cap.num_counters_gp) This logic belongs in common code. Just because AMD doesn't have fixed counters doesn't mean KVM can't have a superfluous "0 == 0" check. > + if (kvm_mediated_pmu_enabled(vcpu) && kvm_pmu_has_perf_global_ctrl(pmu) && Just require the guest to have PERF_GLOBAL_CTRL, I don't see any reason to support v1 PMUs. It adds complexity and weirdness, and I can't imagine there's a use case.