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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9C358C2BB3F for ; Wed, 15 Nov 2023 16:58:52 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1r3JDz-0006im-TD; Wed, 15 Nov 2023 11:58:49 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1r3JDw-0006i9-7r for qemu-devel@nongnu.org; Wed, 15 Nov 2023 11:58:45 -0500 Received: from mail-ed1-x52d.google.com ([2a00:1450:4864:20::52d]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1r3JDu-0000jJ-ND for qemu-devel@nongnu.org; Wed, 15 Nov 2023 11:58:43 -0500 Received: by mail-ed1-x52d.google.com with SMTP id 4fb4d7f45d1cf-545557de8e6so18834a12.0 for ; Wed, 15 Nov 2023 08:58:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1700067521; x=1700672321; darn=nongnu.org; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=oYBIIENIjXruZBqOiGfUysD4sF8Ds8/rSHAguxZgy/Q=; b=1ZG5xW47NGC0DLDbmVanb0C/ctLDofXrpGd3ybavnHzR8oyyB6X6Gfa/KnVhCSKrVT y0sPpHKIF1lFxsb/X/3CylBGiW44B/LxRT61KiQgOX+TijGeaTWUqY8kpxifErvZgJgl Y7EJMRBc33JkC2m9tpbBoxZFIrngn6+a6zTrq6r2ZPYBiIrC2mlyn0c6lLFUUITZIw1A 5sAr0pqCzjqvO7QHCWXGqM9OAQgbn/5T7Uua2I5Fowi/akqY2fFJqjGgFsQYr5HON5da qFthQDpsPXYlbBi8PYvkMwKWWKGMLjKrbx8VIo0Zbq3VAN5VxShHYVs3xDYZIC1jZo7a l+cA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1700067521; x=1700672321; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=oYBIIENIjXruZBqOiGfUysD4sF8Ds8/rSHAguxZgy/Q=; b=a7DEbuFbAiLl4E8jWMlQ165TT4+96zca+gd2bhCgETu+pp4B/1v7Bb1+gToCHfIk44 Jd+likCwhKBGWs6TeBERsrL7kjs5Bu6nAb7Xb9ueydYsbbPYLkwlOFUsf2/QHGx9n9x7 oTu6p2tZDjP8lu59BLbHSRAYl23WpvCaqyOZAbHbpXHlk570nEp3BYaMpZi0VY3rIFH+ SXz2ij9Ilp0B+QV/ck7YXYGojOH5o6JUEyRiOj8on4zumZjuD5vaVyXVmjK7ilLKjHSr U7MQlLIicYBPL34Ct3UjwGLIqFNDLUEKMvqdwP7M2HxV/5KSKj986ma3oypvwgI5bGI4 S1Ag== X-Gm-Message-State: AOJu0Yyg/AWijKcGWf+ej6roRSRUtoGpfHh16hJGSFDRlp8mPg6i+fxk Y2+U4BLFRAy7JP9G+7OHFF//pR0OHXkQLOvO7pmwYw== X-Google-Smtp-Source: AGHT+IG/3hbJgqf6E8siaEx1mfYIdw1DBWuuGNhVu+jsLTaCjxyfAeOq0BWdQKYKWT/MEfBflfOSEP6u/Lyl+vXcRro= X-Received: by 2002:aa7:c05a:0:b0:545:94d:7b with SMTP id k26-20020aa7c05a000000b00545094d007bmr158094edo.4.1700067520897; Wed, 15 Nov 2023 08:58:40 -0800 (PST) MIME-Version: 1.0 References: <20231114205507.3792947-1-venture@google.com> In-Reply-To: From: Patrick Venture Date: Wed, 15 Nov 2023 08:58:29 -0800 Message-ID: Subject: Re: [PATCH] softmmu/memory: use memcpy for multi-byte accesses To: Peter Maydell Cc: pbonzini@redhat.com, peterx@redhat.com, david@redhat.com, philmd@linaro.org, qemu-devel@nongnu.org, Chris Rauer , Peter Foley Content-Type: multipart/alternative; boundary="000000000000adfd59060a33d008" Received-SPF: pass client-ip=2a00:1450:4864:20::52d; envelope-from=venture@google.com; helo=mail-ed1-x52d.google.com X-Spam_score_int: -175 X-Spam_score: -17.6 X-Spam_bar: ----------------- X-Spam_report: (-17.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_MED=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, ENV_AND_HDR_SPF_MATCH=-0.5, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01, USER_IN_DEF_DKIM_WL=-7.5, USER_IN_DEF_SPF_WL=-7.5 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org --000000000000adfd59060a33d008 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, Nov 15, 2023 at 2:35=E2=80=AFAM Peter Maydell wrote: > On Tue, 14 Nov 2023 at 20:55, Patrick Venture wrote: > > Avoids unaligned pointer issues. > > > > It would be nice to be more specific in the commit message here, by > describing what kind of guest behaviour or machine config runs into this > problem, and whether this happens in a situation users are likely to > run into. If the latter, we should consider tagging the commit > with "Cc: qemu-stable@nongnu.org" to have it backported to the > stable release branches. > Thanks! I'll update the commit message with v2. We were seeing this in our infrastructure with unaligned accesses using the pointer dereference as there are no guarantees on alignment of the incoming values. > > thanks > -- PMM > --000000000000adfd59060a33d008 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


=
On Wed, Nov 15, 2023 at 2:35=E2=80=AF= AM Peter Maydell <peter.mayd= ell@linaro.org> wrote:
On Tue, 14 Nov 2023 at 20:55, Patrick Venture <venture@google.com> wro= te:
> Avoids unaligned pointer issues.
>

It would be nice to be more specific in the commit message here, by
describing what kind of guest behaviour or machine config runs into this problem, and whether this happens in a situation users are likely to
run into. If the latter, we should consider tagging the commit
with "Cc: = qemu-stable@nongnu.org" to have it backported to the
stable release branches.

Thanks! I'= ll update the commit message with v2.=C2=A0 We were seeing this in our infr= astructure=C2=A0with unaligned accesses using the pointer dereference as th= ere are no guarantees on alignment of the incoming values.
=C2=A0=

thanks
-- PMM
--000000000000adfd59060a33d008--