From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga07-in.huawei.com (szxga07-in.huawei.com [45.249.212.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E950E179AD; Fri, 2 Feb 2024 07:51:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.35 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706860280; cv=none; b=XSIgrw8xzoiTu4r2j4ZAcy3hCa9zoMrCoSNXd/VCN3OtdmUEk9GfLku/0pjdPUoHkCbHCHGr+Weqy8aZ6PZCX/yhJoEO4+CNZrfNxWgZwYX0dcPPIsvZnlQ3MiBFu85HAKaSrxFYMRVle07zJK5NDSBtIprwyIghQOlyZDdQqCY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706860280; c=relaxed/simple; bh=6CeHjpWTHiilKMN0s9ZZArB1+0+f4ZveMoELOFvHi5g=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=iQrFKv18/zR377u1WmtrVpUxnHHk+zYwdKESi5o6n41QGKF4PCh+ttMMeXxt7J+nc1MuC01SAJa9cqHWIQmMHCIxFtgZgdartJupdxsbThjhqsq3eSPNuVH9hBVtUCCR6pJC20Cu7U5n1opiKL5mwfDFYg1o77lkb2bmnzSq+wg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.35 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.163.44]) by szxga07-in.huawei.com (SkyGuard) with ESMTP id 4TR7Fs67dFz1Q8ZP; Fri, 2 Feb 2024 15:49:21 +0800 (CST) Received: from kwepemm600017.china.huawei.com (unknown [7.193.23.234]) by mail.maildlp.com (Postfix) with ESMTPS id 46058140414; Fri, 2 Feb 2024 15:51:14 +0800 (CST) Received: from [10.174.179.234] (10.174.179.234) by kwepemm600017.china.huawei.com (7.193.23.234) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.35; Fri, 2 Feb 2024 15:51:13 +0800 Message-ID: <39c1e4d2-b1d0-91ae-595e-1add4698dd7f@huawei.com> Date: Fri, 2 Feb 2024 15:51:12 +0800 Precedence: bulk X-Mailing-List: linux-edac@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [PATCH -next v4 2/3] x86/mce: rename MCE_IN_KERNEL_COPYIN to MCE_IN_KERNEL_COPY_MC To: Borislav Petkov CC: Thomas Gleixner , Ingo Molnar , , Dave Hansen , , "H. Peter Anvin" , Tony Luck , Andy Lutomirski , Peter Zijlstra , Andrew Morton , Naoya Horiguchi , , , , Guohanjun References: <20240111135548.3207437-1-tongtiangen@huawei.com> <20240111135548.3207437-3-tongtiangen@huawei.com> <20240131070258.GGZbnwov0g918F-FGz@fat_crate.local> <3009aadd-69d6-c797-20b4-95cf926b6dd9@huawei.com> <20240201142016.GFZbuooG9CRoK90U2C@fat_crate.local> From: Tong Tiangen In-Reply-To: <20240201142016.GFZbuooG9CRoK90U2C@fat_crate.local> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To kwepemm600017.china.huawei.com (7.193.23.234) 在 2024/2/1 22:20, Borislav Petkov 写道: > On Thu, Feb 01, 2024 at 07:37:25PM +0800, Tong Tiangen wrote: >> 在 2024/1/31 15:02, Borislav Petkov 写道: >>> On Thu, Jan 11, 2024 at 09:55:47PM +0800, Tong Tiangen wrote: >>>> Currently, there are some kernel memory copy scenarios is also mc safe >>>> which use copy_mc_to_kernel() or copy_mc_user_highpage(). >>> >>> Both of those end up in copy_mc_enhanced_fast_string() which does >>> EX_TYPE_DEFAULT_MCE_SAFE. >> >> OK, how about this commit msg change? :) >> >> Currently, there are some kernel memory copy scenarios is also mc safe >> which use copy_mc_to_kernel() or copy_mc_user_highpage(), **both of those >> end up in copy_mc_enhanced_fast_string() or copy_mc_fragile() which does >> EX_TYPE_DEFAULT_MCE_SAFE.** >> >> In these scenarios, posion pages need to be isolated too. Therefore, a >> macro similar to MCE_IN_KERNEL_COPYIN is required. For this reason, we >> can rename MCE_IN_KERNEL_COPYIN to MCE_IN_KERNEL_COPY_MC, the new macro >> can be applied to both user-to-kernel mc safe copy and kernel-to-kernel >> mc safe copy. > > Maybe my question wasn't clear: why is that renaming churn needed at > all? What are you "fixing" here? > > What is the problem that you're encountering which needs fixing? This patch is a prepare patch and the next patch is a fix patch, the complete logic of the two patches is as follows: The problem i'm encountering: ------------------------------- In the x86 mce processing, error_context() setting macro MCE_IN_KERNEL_COPYIN to identify copy from user(user-to-kernel copy) for fixup_type EX_TYPE_UACCESS. Then do_machine_check() uses macro MCE_IN_KERNEL_COPYIN to isolate posion page in memory_failure(). Currently, there are some kernel memory copy scenarios is also mc safe which use copy_mc_to_kernel() or copy_mc_user_highpage(), these kernel- to-kernel copy use fixup_type EX_TYPE_DEFAULT_MCE_SAFE. In these scenarios, posion pages need to be isolated too and the current implementation is to actively call memory_failure_queue() when the copy fails. Calling memory_failure_queue() separately is not a good implementation, call it uniformly in do_machine_check() is more reasonable. Solution: ---------- A macro similar to MCE_IN_KERNEL_COPYIN is required, so we can rename MCE_IN_KERNEL_COPYIN to MCE_IN_KERNEL_COPY_MC, the new macro can be applied to both user-to-kernel mc safe copy and kernel-to-kernel mc safe copy, in error_context()，we can set MCE_IN_KERNEL_COPY_MC for both fixup_type EX_TYPE_UACCESS and EX_TYPE_DEFAULT_MCE_SAFE. Do you think it's clear to say so and then we can merge the two patches to make the complete logic clearer in commit msg ? Many thanks. Tong. > > Thx. >