From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753945AbeDJOS3 (ORCPT ); Tue, 10 Apr 2018 10:18:29 -0400 Received: from foss.arm.com ([217.140.101.70]:38928 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753421AbeDJOSZ (ORCPT ); Tue, 10 Apr 2018 10:18:25 -0400 Subject: Re: [PATCH v11 0/4] set VSESR_EL2 by user space and support NOTIFY_SEI notification To: Dongjiu Geng Cc: rkrcmar@redhat.com, corbet@lwn.net, christoffer.dall@linaro.org, marc.zyngier@arm.com, linux@armlinux.org.uk, catalin.marinas@arm.com, rjw@rjwysocki.net, bp@alien8.de, lenb@kernel.org, kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-acpi@vger.kernel.org, devel@acpica.org, huangshaoyu@huawei.com, zhengxiang9@huawei.com References: <1523309796-36423-1-git-send-email-gengdongjiu@huawei.com> From: James Morse Message-ID: Date: Tue, 10 Apr 2018 15:15:32 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <1523309796-36423-1-git-send-email-gengdongjiu@huawei.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Dongjiu Geng, On 09/04/18 22:36, Dongjiu Geng wrote: > 1. Detect whether KVM can set set guest SError syndrome > 2. Support to Set VSESR_EL2 and inject SError by user space. > 3. Support live migration to keep SError pending state and VSESR_EL2 value. > 4. ACPI 6.1 adds support for NOTIFY_SEI as a GHES notification mechanism, so support this > notification in software, KVM or kernel ARCH code call handle_guest_sei() to let ACP driver > to handle this notification. Please don't post code during the merge-window, will this apply to v4.17-rc1? We can't know until its tagged. This series is doing two separate things, please split it into two series. But on the ACPI front: I don't see how any OS can support your NOTIFY_SEI when firmware is ignoring the normal world's PSTATE.A. The latest lobe of that discussion was on the list here: https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1611496.html As it is, we would need to spot SError being delivered while SError is masked, spray nasty messages about firmware being horrifically buggy, then panic(). For a corrected error, this looks bad, but its preferable to letting firmware silently overwrite the exception registers, causing linux to spin through the vectors 'eret' with all exceptions masked. I still think its best to wait for firmware that does the right thing. Thanks, James