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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id E4964C433F5 for ; Wed, 25 May 2022 20:16:47 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4035E8D0003; Wed, 25 May 2022 16:16:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3B0DF8D0002; Wed, 25 May 2022 16:16:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2C2AB8D0003; Wed, 25 May 2022 16:16:47 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 204C68D0002 for ; Wed, 25 May 2022 16:16:47 -0400 (EDT) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id E11E260405 for ; Wed, 25 May 2022 20:16:46 +0000 (UTC) X-FDA: 79505373612.03.9953DAC Received: from mail-vk1-f176.google.com (mail-vk1-f176.google.com [209.85.221.176]) by imf07.hostedemail.com (Postfix) with ESMTP id D6B8F4002A for ; Wed, 25 May 2022 20:16:35 +0000 (UTC) Received: by mail-vk1-f176.google.com with SMTP id m203so10387098vke.13 for ; Wed, 25 May 2022 13:16:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:from:date:message-id:subject:to:cc; bh=sEG0icEbQWzQToljyqBgD3aSPQ/mar2lnW/ygu4neoY=; b=eEqJ7TQi6I6W8fbEV9Ibmb7lons3Vl5rNCaekxwVLzqN0iym/F9GFmW3m8TS31Fe45 ePM+S2RHy/r20laDdii5e9VQiY5RSKaoLD/pgXZ2ghVStHsVV5ugwG8dbXSzeW5nOv7D MC9/aFVH0Dx69kSHo86+3frP64Ss6OcL9dq7i3UzIX7lf9daLy05BVveI+yKZVbFg464 RBO63ztSg2not7N8aYKfyAshrQzRJpnlQfMOl16HBb484uCMYX8FkRSYqNpNIp2ZE1j2 AQJiXPAQQOuoJxAGTQ7Gw+Iev/omSlrkzV5CgbHvyOKaLku4CDlo7dualO3zn2tzIivB nyDA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:from:date:message-id:subject:to:cc; bh=sEG0icEbQWzQToljyqBgD3aSPQ/mar2lnW/ygu4neoY=; b=eV/HOSdadNqpuI93SBpnYKY+QjruN02B/x05506I+n2hPo/TqLoIbBPlF5Gq8B7OBQ KWxrYf28SLU+e7+4TiLx6N9OGLvKTi+GlXdZRH2QHZ8nEXqmZbZJaXzrRPigomya1+rE 6PtmL0syll6CfCElqkydTCzof1TUEuAe9xIYLDQdKNEFO1eAw+20/IjMm4smItG4JYQj aVFRAA2TOQrnUrIPCCgsQ937ZwGnPuYeH1IhDStqQsfSB5VFS3jl5+ehv6WX89u8ghIB /Yv7L/X1k9fSCllxQ2t0aZgnm4VGV1YoOzEzsfzTB27ZBVfPWdwpS60lay4ZQlP9vi5t EibQ== X-Gm-Message-State: AOAM530VGq5PKWVbykFqLGZWDXlpMwTFa4nqVPBJH+eDbhG+ltr2lLAS Fiwor+bV2GL/z5DUggTlRcrTwzLK03KO8UrmJUJl4g== X-Google-Smtp-Source: ABdhPJxXTD0b0wGt11g6Sf3EIcNgykMMnDOGoXDZJlAhtASlMQY8J+Li2flc5Z6ipSE6ZXPSEPSpTccxmE+am9GnerQ= X-Received: by 2002:ac5:cdec:0:b0:358:269a:8a24 with SMTP id v12-20020ac5cdec000000b00358269a8a24mr2737096vkn.22.1653509805414; Wed, 25 May 2022 13:16:45 -0700 (PDT) MIME-Version: 1.0 From: Jue Wang Date: Wed, 25 May 2022 13:16:34 -0700 Message-ID: Subject: Re: [PATCH 0/3] recover hardware corrupted page by virtio balloon To: pizhenwei@bytedance.com Cc: Andrew Morton , David Hildenbrand , jasowang@redhat.com, LKML , Linux MM , mst@redhat.com, =?UTF-8?B?SE9SSUdVQ0hJIE5BT1lBKOWggOWPoyDnm7TkuZ8p?= , Paolo Bonzini , Peter Xu , qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: D6B8F4002A X-Stat-Signature: ohz48686ri85rp1wurht46jygf49fxpn X-Rspam-User: Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=eEqJ7TQi; spf=pass (imf07.hostedemail.com: domain of juew@google.com designates 209.85.221.176 as permitted sender) smtp.mailfrom=juew@google.com; dmarc=pass (policy=reject) header.from=google.com X-HE-Tag: 1653509795-649251 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000007, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Some points to consider: The injected MCE has _done_ the damages to guest workload. Recovering the guest poisoned memory doesn't help with the already happened guest workload memory corruption / loss / interruption due to injected MCEs. The hypervisor _must_ emulate poisons identified in guest physical address space (could be transported from the source VM), this is to prevent silent data corruption in the guest. With a paravirtual approach like this patch series, the hypervisor can clear some of the poisoned HVAs knowing for certain that the guest OS has isolated the poisoned page. I wonder how much value it provides to the guest if the guest and workload are _not_ in a pressing need for the extra KB/MB worth of memory. Thanks, -Jue