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[147.11.224.80]) by smtp.gmail.com with ESMTPSA id c13sm1639349pfo.35.2020.10.22.03.16.09 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 22 Oct 2020 03:16:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=/mU1ILRS8rfSLtKIKKtvN0NpPwtch42REJWHZodQfho=; b=r2UnRY9/+GaMysxcN4EuHBf/zm72f5DLKYFWiD5FBVLbgJ7VJ/fxgoJwAWhXIia8NE 0toNJWhay8NjYHVj+Xsm+B7wI2BAYfBE14JhZCawuNtkS1tzQJC/5V/dF64DilIVrFoB su1AJIRT6bSHWzanVzbS/yl9PgOnl9Bf4tGMrYBE+6/aD5nKeZg+Kf45YUeXcDcVp6Bd O9gDa3/8pTNy+zwJoXEZkRI+RhBZkOqC0TQ7GWWKVm4L5/n7FTDU997itvvnR6I3Ltlm aAaCDhmMsJ6ggpUb3Knqj2foX/rg4OpLkD1suotp0AlStTfLpCENPJKhCmIoU4gpCAjK Eo8A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=/mU1ILRS8rfSLtKIKKtvN0NpPwtch42REJWHZodQfho=; b=EcpLiNZ5cD4ZgbS6pd74gDTURvfwHsl1f7UuVCd3G1ZkTGrLsttTz/YibeQHSbLbxK osSXuZ2rtgEh6CiWflxQqDwmmFXw4SfdBJdbqtAlh+6M3zVgcBQS0FJPRWn91A+vsBSQ cQyzhsrBKQgP8eXsgoCKQxRS7OpdVtTAmdLkbSK3Hylj3dDjs6kvIFXZbws+fh0c98ci jN+HuTVUjpmojbeof0BC4SkaiRia8fMBmmY1yHJZDTdeibiLHwLp7PTX9WYC+fUYYEtW Nlv4xu5MGx/8p88GWcoaJloWJYJZ3/AJsWEQ6mrFWtO0mmPYwxujU4tLEMtopfKoKwRO Q5uQ== X-Gm-Message-State: AOAM533BMXksKjwvlfkdgsEBGKH4Az3vwB1CEAiK+9LDXKzAL6DREZ1Q yM/X48HHvyxgJzosq7hzIvU= X-Google-Smtp-Source: ABdhPJzUpYcG6i+DjmJz7wQeD8QddB83x9az/VEUONMEwVDQX8oexnXj9/Yxft5kFewDVDc6uzI0Lw== X-Received: by 2002:a17:90a:e147:: with SMTP id ez7mr1754836pjb.72.1603361772252; Thu, 22 Oct 2020 03:16:12 -0700 (PDT) From: Bin Meng To: Eduardo Habkost , Paolo Bonzini , Richard Henderson , qemu-devel@nongnu.org Subject: [PATCH] target/i386: seg_helper: Correct segement selector nullification in the RET/IRET helper Date: Thu, 22 Oct 2020 18:16:02 +0800 Message-Id: <1603361762-43062-1-git-send-email-bmeng.cn@gmail.com> X-Mailer: git-send-email 2.7.4 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2607:f8b0:4864:20::1043; envelope-from=bmeng.cn@gmail.com; helo=mail-pj1-x1043.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+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @gmail.com) Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" 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(-) diff --git a/target/i386/seg_helper.c b/target/i386/seg_helper.c index be88938..d8766d8 100644 --- a/target/i386/seg_helper.c +++ b/target/i386/seg_helper.c @@ -2108,7 +2108,10 @@ static inline void validate_seg(CPUX86State *env, in= t seg_reg, int cpl) if (!(e2 & DESC_CS_MASK) || !(e2 & DESC_C_MASK)) { /* data or non conforming code segment */ if (dpl < cpl) { - cpu_x86_load_seg_cache(env, seg_reg, 0, 0, 0, 0); + cpu_x86_load_seg_cache(env, seg_reg, 0, + env->segs[seg_reg].base, + env->segs[seg_reg].limit, + env->segs[seg_reg].flags); } } } --=20 2.7.4