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 X-Spam-Level: X-Spam-Status: No, score=-6.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F04F0C00A89 for ; Mon, 2 Nov 2020 08:21:17 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 65BCD206B7 for ; Mon, 2 Nov 2020 08:21:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="OI9EZxVq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 65BCD206B7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:51452 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kZV5Y-00023p-8B for qemu-devel@archiver.kernel.org; Mon, 02 Nov 2020 03:21:16 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:55662) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kZV4k-0001Wc-Fo for qemu-devel@nongnu.org; Mon, 02 Nov 2020 03:20:26 -0500 Received: from mail-yb1-xb41.google.com ([2607:f8b0:4864:20::b41]:36732) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kZV4f-00077u-0B for qemu-devel@nongnu.org; Mon, 02 Nov 2020 03:20:26 -0500 Received: by mail-yb1-xb41.google.com with SMTP id f140so11051019ybg.3 for ; Mon, 02 Nov 2020 00:20:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=DbqVb66d+WqD8vzO7ZytnaI+y+NeU/Mv0ZeGlITaOYg=; b=OI9EZxVqrAWkX/4Gta+Fx8CJWYS272tEsSZXOrTIcg0eyYdfP+EAibGTzE0mNR8s5H Qaa/xTdflhwP08h0uarLdXcZmtfQJN+H0wTIYVF/xcYsdHnxWIrsGuwVloeg4Ns6NCXE OnBZC543TGGsZWTbBpWefHWtGRfcaydZPDyNFFWdulKs4BlkZi9WL9NZRgWzaDR9BJMm v3XJtenw6ONnhtrH0kHDGUa9206YfRlPUt3ul9Y16hEVON6dcb6fLVC1BzzdyQtyJouu qOCxqPVJWsX4uuTeUzhaXopcA2qO9D2C83O6p+mC0m3S/gdQIT6HNZTOy/6ECfjREapb IDKw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=DbqVb66d+WqD8vzO7ZytnaI+y+NeU/Mv0ZeGlITaOYg=; b=OS7TTSlj9NM3yVCWD3VcJEeddq7qma+dZ6UKMoQMueVO4zi79N1yoY7eUHzp4Tkf+l cmcTSYJ1lkax4yB7e/ULCBSUjkuv0hUJTNq/qK6DsG6d+mEj+Cm7HQnKBaXP/P/C3h7C jwt8GKYcNZi0nLJxHbkBTMHUVpCUyRoRu5bxfoflnwydng2LM938+aKFU0uvbWxkKoiF /fmDbD/c3+VvJjiuE82xxgbwuOPsJCnZrMN7zh+prlILyPyKajmolC9ogBrXtPC8DDGL YcEdMOvdk2TCO8hGwDHCrfdyfyDvvfts9SoVCXJttTLQlaB2lRLqWThVP/baaaHfsAzd r20A== X-Gm-Message-State: AOAM533Wc27LdHDJcHN+K65xZC2drFE7XjqLFQzIeEe7K7KwmF3BnIp7 51ta6NF6MvmuwNeK09DRPyl823HXtJq0E7gWQ+o= X-Google-Smtp-Source: ABdhPJyLF7uFzzgB+lfKM0WdxKa0/vFCQgzI0l2x/IUKd/Fcry55T+/MI1ucHIN0e1qHq7OMZvQxFH2vU8AAsWhoQnc= X-Received: by 2002:a25:328a:: with SMTP id y132mr18842408yby.306.1604305219869; Mon, 02 Nov 2020 00:20:19 -0800 (PST) MIME-Version: 1.0 References: <1603361762-43062-1-git-send-email-bmeng.cn@gmail.com> In-Reply-To: <1603361762-43062-1-git-send-email-bmeng.cn@gmail.com> From: Bin Meng Date: Mon, 2 Nov 2020 16:20:08 +0800 Message-ID: Subject: Re: [PATCH] target/i386: seg_helper: Correct segement selector nullification in the RET/IRET helper To: Eduardo Habkost , Paolo Bonzini , "qemu-devel@nongnu.org Developers" , Richard Henderson Content-Type: text/plain; charset="UTF-8" Received-SPF: pass client-ip=2607:f8b0:4864:20::b41; envelope-from=bmeng.cn@gmail.com; helo=mail-yb1-xb41.google.com X-detected-operating-system: by eggs.gnu.org: No matching host in p0f cache. That's all we know. X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Bin Meng Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Oct 22, 2020 at 6:16 PM Bin Meng wrote: > > From: Bin Meng > > Per the SDM, when returning to outer privilege level, for segment > registers (ES, FS, GS, and DS) if the check fails, the segment > selector becomes null, but QEMU clears the base/limit/flags as well > as nullifying the segment selector, which should be a spec violation. > > Real hardware seems to be compliant with the spec, at least on one > Coffee Lake board I tested. > > Signed-off-by: Bin Meng > --- > > target/i386/seg_helper.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > Ping?