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.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 6DAACC282EC for ; Mon, 17 Mar 2025 11:03:33 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.916547.1321619 (Exim 4.92) (envelope-from ) id 1tu8Fh-0005vb-Bq; Mon, 17 Mar 2025 11:03:25 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 916547.1321619; Mon, 17 Mar 2025 11:03:25 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1tu8Fh-0005vU-7t; Mon, 17 Mar 2025 11:03:25 +0000 Received: by outflank-mailman (input) for mailman id 916547; Mon, 17 Mar 2025 11:03:24 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1tu8Fg-0005vO-5B for xen-devel@lists.xenproject.org; Mon, 17 Mar 2025 11:03:24 +0000 Received: from mail-wm1-x330.google.com (mail-wm1-x330.google.com [2a00:1450:4864:20::330]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id 70ea1ff9-031f-11f0-9899-31a8f345e629; Mon, 17 Mar 2025 12:03:22 +0100 (CET) Received: by mail-wm1-x330.google.com with SMTP id 5b1f17b1804b1-43cef035a3bso13721825e9.1 for ; Mon, 17 Mar 2025 04:03:22 -0700 (PDT) Received: from [10.156.60.236] (ip-037-024-206-209.um08.pools.vodafone-ip.de. [37.24.206.209]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-43d200fad64sm101304045e9.25.2025.03.17.04.03.21 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 17 Mar 2025 04:03:21 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 70ea1ff9-031f-11f0-9899-31a8f345e629 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1742209402; x=1742814202; darn=lists.xenproject.org; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:from:to:cc:subject:date:message-id:reply-to; bh=FQjtTdlwB+8VKnxBbUM1jaL7uHemp+a4JRqYrdzGBqA=; b=bq2X/raHh7dAQj32k8bCzYwv4WS6Y+fUvaSIaztJ+kF7q2JH+CZ0YtsgVJcO/Q4eG5 OFXV6+GQIOXAz4YmWfU0mEO6ANA4pJDPSelbEwlad0CSccqK90qPmgNoAtC28LUQdj4E OTQkRTeAexY8Krf4YwxNpfPOXflTYsMzV1mpaG4DSTrv/ung4fDa16hUidXG6vJhgQUT BnuXpTQNCDwjSAWoonqc9Q4ScU08B4CO5gUm2BpdhkyKVNCGmZTx+R8kXFM7LWrc1GKF e3uQAoZ97QQC6uLNbUAxE7u6PAiIx2vKWefa4De/MjAOXCNFV5A9R39tqaXRdTOh9kzi V9AA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1742209402; x=1742814202; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=FQjtTdlwB+8VKnxBbUM1jaL7uHemp+a4JRqYrdzGBqA=; b=HWcMdEvyKkSxUf8uqMLhSEjx8rSqEqbu58ckj3EQcgfW/i5bIbOgWfem7xNt324L3U JfkvWWg1XlFMzA3NiRZPw75l8MdNCXQV2p0oZXWtY11xy8De7tQdHlPjf1fgXsq9kC+N C55vB668oFOgMJxCDP/0XAJLTAeHeFZ3DGqcYv6FMa0iETLYylsNx9lc4Dq7KisSvCy+ mU+wy//HO4ouF5rVk96eVZxMjVTWoMVojFIxwvSZS5ibbfwABeXsXtGoOrWJh6jl28Mr vQm1hZjm9Vmh724JFdnOhaBQIa6ehy3tr7odXPRGphZcS9vGVXNrdqv4B2vxobVZCzhc DeUQ== X-Forwarded-Encrypted: i=1; AJvYcCU39Y0s9fejvv2neBJrwCKqYhNtxt8mgR2u8oqNE+4bjjhUsu6agJiC0j03oCGKg6VsrLzr7+4kmvE=@lists.xenproject.org X-Gm-Message-State: AOJu0Yy3UnVVlyrnrWooAhb1Mi/VKsdAuZX4f9OWpKBNMQKrjcygd7co Vn4cWx6Wjmd4Pv8C4evFhMNAhHmFNNyUQAaubI1Dc0e1xlKuR2iCQFcIjJpfFlpkTbw6XeP42CQ = X-Gm-Gg: ASbGncul1LYsZ1scwLOblH/yZrSXm5QLkVsjxMj2Rv/5lrYpDGmO5o0HvD0f02+0jjV Te26VQN+Vo4hIQcN0NAsHZLOAs4P8zeggAFHhFv9Ax9zwDSGgbt1krWkem49e0KmHI4ZSyUUnkk 5gfXxaUgvbcKxkb/iID8HEXujomxzzdcmgpid7QVlEbs9iOLlnTqqSy7Gca+ajP2KMRWP6dffOw gdlRpZRjSRxK+2MXAz5nEIO2LWBF2h+hs2Zb/QCzbaXRqVMK3lH+ce20aIUIz3wgOBg7kTLBihV 12FhTseoemiq2Q26gbNayuCawBzIfeuH0zA7OZvZ84z7eSguXUWOpOu4MfLZAba4LPm/c6LNMc9 sE/IJdsbx0OTVxPJc9X4hekJjvA7xVA== X-Google-Smtp-Source: AGHT+IG7O7EahYML0G9SHVk+E51H00Zh0d9XywrkbEkB17aKdnmHO+kgzbB3PMYRDuhlG9Q/8uyL9Q== X-Received: by 2002:a05:6000:400c:b0:391:a74:d7dc with SMTP id ffacd0b85a97d-39720e3c898mr13514945f8f.50.1742209401434; Mon, 17 Mar 2025 04:03:21 -0700 (PDT) Message-ID: <0141cd64-348b-41fd-8a45-d8e236e60cb1@suse.com> Date: Mon, 17 Mar 2025 12:03:20 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 4/8] Revert "x86/traps: 'Fix' safety of read_registers() in #DF path" To: Andrew Cooper Cc: =?UTF-8?Q?Roger_Pau_Monn=C3=A9?= , Xen-devel References: <20250311211043.3629696-1-andrew.cooper3@citrix.com> <20250311211043.3629696-5-andrew.cooper3@citrix.com> Content-Language: en-US From: Jan Beulich Autocrypt: addr=jbeulich@suse.com; keydata= xsDiBFk3nEQRBADAEaSw6zC/EJkiwGPXbWtPxl2xCdSoeepS07jW8UgcHNurfHvUzogEq5xk hu507c3BarVjyWCJOylMNR98Yd8VqD9UfmX0Hb8/BrA+Hl6/DB/eqGptrf4BSRwcZQM32aZK 7Pj2XbGWIUrZrd70x1eAP9QE3P79Y2oLrsCgbZJfEwCgvz9JjGmQqQkRiTVzlZVCJYcyGGsD /0tbFCzD2h20ahe8rC1gbb3K3qk+LpBtvjBu1RY9drYk0NymiGbJWZgab6t1jM7sk2vuf0Py O9Hf9XBmK0uE9IgMaiCpc32XV9oASz6UJebwkX+zF2jG5I1BfnO9g7KlotcA/v5ClMjgo6Gl MDY4HxoSRu3i1cqqSDtVlt+AOVBJBACrZcnHAUSuCXBPy0jOlBhxPqRWv6ND4c9PH1xjQ3NP nxJuMBS8rnNg22uyfAgmBKNLpLgAGVRMZGaGoJObGf72s6TeIqKJo/LtggAS9qAUiuKVnygo 3wjfkS9A3DRO+SpU7JqWdsveeIQyeyEJ/8PTowmSQLakF+3fote9ybzd880fSmFuIEJldWxp Y2ggPGpiZXVsaWNoQHN1c2UuY29tPsJgBBMRAgAgBQJZN5xEAhsDBgsJCAcDAgQVAggDBBYC AwECHgECF4AACgkQoDSui/t3IH4J+wCfQ5jHdEjCRHj23O/5ttg9r9OIruwAn3103WUITZee e7Sbg12UgcQ5lv7SzsFNBFk3nEQQCACCuTjCjFOUdi5Nm244F+78kLghRcin/awv+IrTcIWF hUpSs1Y91iQQ7KItirz5uwCPlwejSJDQJLIS+QtJHaXDXeV6NI0Uef1hP20+y8qydDiVkv6l IreXjTb7DvksRgJNvCkWtYnlS3mYvQ9NzS9PhyALWbXnH6sIJd2O9lKS1Mrfq+y0IXCP10eS FFGg+Av3IQeFatkJAyju0PPthyTqxSI4lZYuJVPknzgaeuJv/2NccrPvmeDg6Coe7ZIeQ8Yj t0ARxu2xytAkkLCel1Lz1WLmwLstV30g80nkgZf/wr+/BXJW/oIvRlonUkxv+IbBM3dX2OV8 AmRv1ySWPTP7AAMFB/9PQK/VtlNUJvg8GXj9ootzrteGfVZVVT4XBJkfwBcpC/XcPzldjv+3 HYudvpdNK3lLujXeA5fLOH+Z/G9WBc5pFVSMocI71I8bT8lIAzreg0WvkWg5V2WZsUMlnDL9 mpwIGFhlbM3gfDMs7MPMu8YQRFVdUvtSpaAs8OFfGQ0ia3LGZcjA6Ik2+xcqscEJzNH+qh8V m5jjp28yZgaqTaRbg3M/+MTbMpicpZuqF4rnB0AQD12/3BNWDR6bmh+EkYSMcEIpQmBM51qM EKYTQGybRCjpnKHGOxG0rfFY1085mBDZCH5Kx0cl0HVJuQKC+dV2ZY5AqjcKwAxpE75MLFkr wkkEGBECAAkFAlk3nEQCGwwACgkQoDSui/t3IH7nnwCfcJWUDUFKdCsBH/E5d+0ZnMQi+G0A nAuWpQkjM1ASeQwSHEeAWPgskBQL In-Reply-To: <20250311211043.3629696-5-andrew.cooper3@citrix.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 11.03.2025 22:10, Andrew Cooper wrote: > This reverts commit 6065a05adf152a556fb9f11a5218c89e41b62893. > > The discussed "proper fix" has now been implemented, and the #DF path no > longer writes out-of-bounds. Restore the proper #DF IST pointer. > > Signed-off-by: Andrew Cooper Acked-by: Jan Beulich > --- a/xen/arch/x86/cpu/common.c > +++ b/xen/arch/x86/cpu/common.c > @@ -847,13 +847,7 @@ void load_system_tables(void) > tss->ist[IST_MCE - 1] = stack_top + (1 + IST_MCE) * PAGE_SIZE; > tss->ist[IST_NMI - 1] = stack_top + (1 + IST_NMI) * PAGE_SIZE; > tss->ist[IST_DB - 1] = stack_top + (1 + IST_DB) * PAGE_SIZE; > - /* > - * Gross bodge. The #DF handler uses the vm86 fields of cpu_user_regs > - * beyond the hardware frame. Adjust the stack entrypoint so this > - * doesn't manifest as an OoB write which hits the guard page. > - */ > - tss->ist[IST_DF - 1] = stack_top + (1 + IST_DF) * PAGE_SIZE - > - (sizeof(struct cpu_user_regs) - offsetof(struct cpu_user_regs, es)); > + tss->ist[IST_DF - 1] = stack_top + (1 + IST_DF) * PAGE_SIZE; And one of these "es is special" also gone. Jan