From mboxrd@z Thu Jan 1 00:00:00 1970 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 E898EEB64DC for ; Fri, 30 Jun 2023 14:28:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232420AbjF3O2g (ORCPT ); Fri, 30 Jun 2023 10:28:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37770 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230462AbjF3O2d (ORCPT ); Fri, 30 Jun 2023 10:28:33 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 00CA13AAD for ; Fri, 30 Jun 2023 07:28:32 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id 3f1490d57ef6-bfee66a6398so1660483276.3 for ; Fri, 30 Jun 2023 07:28:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1688135312; x=1690727312; h=to:from:subject:message-id:references:mime-version:in-reply-to:date :from:to:cc:subject:date:message-id:reply-to; bh=FRMN0RaJzHYAyXMyga4ctoKFK0XbdFwKMcCpI/juWEU=; b=am0dqL8tuDa5C5eAHIW+joInjR/a055ifnjo+XJOjG+qcVcc7ILCAG4uVycrP+mFcK FAn7/4Eq65Dj34v0YTkD597Txnxmc+yQPxISjWUK0rVlT9d0BVlp9L1X8s3nUnCLaM5/ gouPMfh60JcbsvPSV6U19hQ1Yf139QyGWx9RbOfUmcfTgQVSrgUU6K2AbQpJnLu9iLO7 fJs1jOtYs29gobQ1SfpvZJE3vM8gac16O3IHANQE9D6y/hF72mLvpEzVgIxJRx/Kz32Q xEJ560pfJvDmiswQ/NIhDKt5VHKXP+GaRT/ApbOWVkNFq+RXhECgD5nn/0xPbotUDJsA nUFw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1688135312; x=1690727312; h=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=FRMN0RaJzHYAyXMyga4ctoKFK0XbdFwKMcCpI/juWEU=; b=Y/8PR6xx6ObDdROl7oVqIHPM0OcEM3LcrtkMeRKkChUHHBNDEdVjVhbNPgso88OvMW zzj0+0gav3z57yV39e6+HYSJrgBy2J8sFBuwC2Ppofcu1lbAeOW9yxKoWXQ8bx4whLdf BZ/Hvc3CdwiHB0ct8LQqlsJ0529ZiYnUBDpeWAnIaA8br06hPk6aqz5MFlMgNu2rZ28M uBhyWMmiUgM0mtwGVpCR8ElSWsb3bz0SLjZ2CRw8zTIj3mty4AO/AgEgrEY10q2dnu0R qpHoYuLPQstxJZpGjVzgh4+7IiojMQ3OKJBpccqBIuFFaKhx5egRtMVFbfkYtdtHrS0z LS5Q== X-Gm-Message-State: ABy/qLadakyoSrzBEKdWAupbmJmg+pWhHKeDtRXQRWGvUN1/pw/7gDLK obPYf8g4GBxWvt3Oe6TO5SOjGd+Zqvs= X-Google-Smtp-Source: APBJJlHOOLORAgt37+VIRI8/WOvT0fj13Al51joe6mbUicQPhnu539E1jFNneO9sew/vI5ZTflnm86W+tdM= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a25:f602:0:b0:c11:bb8d:75f4 with SMTP id t2-20020a25f602000000b00c11bb8d75f4mr17391ybd.8.1688135312230; Fri, 30 Jun 2023 07:28:32 -0700 (PDT) Date: Fri, 30 Jun 2023 07:28:29 -0700 In-Reply-To: Mime-Version: 1.0 References: <20230504120042.785651-1-rkagan@amazon.de> Message-ID: Subject: Re: [PATCH] KVM: x86: vPMU: truncate counter value to allowed width From: Sean Christopherson To: Roman Kagan , Jim Mattson , Paolo Bonzini , Eric Hankland , kvm@vger.kernel.org, Dave Hansen , Like Xu , x86@kernel.org, Thomas Gleixner , linux-kernel@vger.kernel.org, "H. Peter Anvin" , Borislav Petkov , Ingo Molnar , Mingwei Zhang Content-Type: text/plain; charset="us-ascii" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 30, 2023, Roman Kagan wrote: > On Thu, Jun 29, 2023 at 05:11:06PM -0700, Sean Christopherson wrote: > > @@ -74,6 +74,14 @@ static inline u64 pmc_read_counter(struct kvm_pmc *pmc) > > return counter & pmc_bitmask(pmc); > > } > > > > +static inline void pmc_write_counter(struct kvm_pmc *pmc, u64 val) > > +{ > > + if (pmc->perf_event && !pmc->is_paused) > > + perf_event_set_count(pmc->perf_event, val); > > + > > + pmc->counter = val; > > Doesn't this still have the original problem of storing wider value than > allowed? Yes, this was just to fix the counter offset weirdness. My plan is to apply your patch on top. Sorry for not making that clear.