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 CFD27C433EF for ; Mon, 22 Nov 2021 14:17:10 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 370276B006C; Mon, 22 Nov 2021 09:16:55 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 2F8ED6B0072; Mon, 22 Nov 2021 09:16:55 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1999C6B0073; Mon, 22 Nov 2021 09:16:55 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0020.hostedemail.com [216.40.44.20]) by kanga.kvack.org (Postfix) with ESMTP id 0A5EC6B006C for ; Mon, 22 Nov 2021 09:16:55 -0500 (EST) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id AA1C788CDA for ; Mon, 22 Nov 2021 14:16:44 +0000 (UTC) X-FDA: 78836767128.08.D0F2081 Received: from mail-lf1-f48.google.com (mail-lf1-f48.google.com [209.85.167.48]) by imf27.hostedemail.com (Postfix) with ESMTP id CC16F70000B9 for ; Mon, 22 Nov 2021 14:16:42 +0000 (UTC) Received: by mail-lf1-f48.google.com with SMTP id t26so81207088lfk.9 for ; Mon, 22 Nov 2021 06:16:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shutemov-name.20210112.gappssmtp.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=P+4zN2N2GD5InVPRag20OPT/f7vJcEHsDBTk4URQjTY=; b=i660LRu/4c8k5hZyBAeiN7vx0DBSwtD8jpUkhNkSzxlWCRi0bijMvkNpekOr7ODcqf UC0FELTodvWUnOuZjym86GSTh/2Zk2G58nuT2v5lRYn46uzum5yI7DHmlQ4HhO1Nm7T/ aQH9kqwRvEP2U9SXB4mugfIDYeVG8Q83mR0ziru1aeYKVDvndcWcO2dGj6xLJFbVDXKn nChK1SZIjg7CvjRVK6vC6dXSOLsBwzmizr4u7jHyKx6OVdI3BWNtfNkiZu97/IcU80/r He6oR52eZ+2bEqk/XkG670vHL3LQAnjJvaBUqzPuTmX2lMgEKeEbNFXL0x2jxrgBfVWC MnwA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=P+4zN2N2GD5InVPRag20OPT/f7vJcEHsDBTk4URQjTY=; b=exKyzvgYIrpfP5I0TaqMJUH9jfJktEbPqDOXKYaWrduJ2KTFhpoxFuhl03w0hUv2gV pS660uncVO2AJcRn2FXCDQFkZ27ac8A4z1wAYzWiIfhCjcvo841KJcqfhUNZPz7CBa5v YNODZYpyYBnexNpBUDZ7yRrPTvyXgeYTeHWVItZi3cWIXMLRfbTrkN/O1SBWxfcq8Ign yi2rrjHGPjattxusnzK+ITmr/ZrSQIx2IK0opeu2k5F6INo2yu5GSa1qmYJPlcdACJ0m 25TLG8gPvQ5Ovq3PBkcNjYReSqr/kh0ApRsslAWYfaKG/yKoXdQd6e0arWQQaweCe6TU wbrw== X-Gm-Message-State: AOAM533akoYZ5u3tG3hf0xYagFc44fnQ6tGuruPTN8n91OY8EObUFOHu 5ZTf8tCEsF7Ln/XDYJe7i4AqrA== X-Google-Smtp-Source: ABdhPJwA2Y8gfA+st0HYZ/WwMV2AWc6rzJCATTeuU95BmoAecu1lVYYz4BBqsxxXP2KWDyyXt38ykg== X-Received: by 2002:a2e:8189:: with SMTP id e9mr52166761ljg.333.1637590602046; Mon, 22 Nov 2021 06:16:42 -0800 (PST) Received: from box.localdomain ([86.57.175.117]) by smtp.gmail.com with ESMTPSA id q24sm979041lfp.103.2021.11.22.06.16.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Nov 2021 06:16:41 -0800 (PST) Received: by box.localdomain (Postfix, from userid 1000) id 83FF5103610; Mon, 22 Nov 2021 17:16:47 +0300 (+03) Date: Mon, 22 Nov 2021 17:16:47 +0300 From: "Kirill A. Shutemov" To: Chao Peng Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, qemu-devel@nongnu.org, Wanpeng Li , jun.nakajima@intel.com, david@redhat.com, "J . Bruce Fields" , dave.hansen@intel.com, "H . Peter Anvin" , ak@linux.intel.com, Jonathan Corbet , Joerg Roedel , x86@kernel.org, Hugh Dickins , Ingo Molnar , Borislav Petkov , luto@kernel.org, Thomas Gleixner , Vitaly Kuznetsov , Jim Mattson , Sean Christopherson , susie.li@intel.com, Jeff Layton , john.ji@intel.com, Yu Zhang , Paolo Bonzini , Andrew Morton , "Kirill A . Shutemov" Subject: Re: [RFC v2 PATCH 13/13] KVM: Enable memfd based page invalidation/fallocate Message-ID: <20211122141647.3pcsywilrzcoqvbf@box.shutemov.name> References: <20211119134739.20218-1-chao.p.peng@linux.intel.com> <20211119134739.20218-14-chao.p.peng@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211119134739.20218-14-chao.p.peng@linux.intel.com> X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: CC16F70000B9 X-Stat-Signature: nyn1kcnubbfft5uakd4sxkstib14wytq Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=shutemov-name.20210112.gappssmtp.com header.s=20210112 header.b="i660LRu/"; dmarc=none; spf=none (imf27.hostedemail.com: domain of kirill@shutemov.name has no SPF policy when checking 209.85.167.48) smtp.mailfrom=kirill@shutemov.name X-HE-Tag: 1637590602-366974 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Nov 19, 2021 at 09:47:39PM +0800, Chao Peng wrote: > Since the memory backing store does not get notified when VM is > destroyed so need check if VM is still live in these callbacks. > > Signed-off-by: Yu Zhang > Signed-off-by: Chao Peng > --- > virt/kvm/memfd.c | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/virt/kvm/memfd.c b/virt/kvm/memfd.c > index bd930dcb455f..bcfdc685ce22 100644 > --- a/virt/kvm/memfd.c > +++ b/virt/kvm/memfd.c > @@ -12,16 +12,38 @@ > #include > const static struct guest_mem_ops *memfd_ops; > > +static bool vm_is_dead(struct kvm *vm) > +{ > + struct kvm *kvm; > + > + list_for_each_entry(kvm, &vm_list, vm_list) { > + if (kvm == vm) > + return false; > + } I don't think this is enough. The struct kvm can be freed and re-allocated from the slab and this function will give false-negetive. Maybe the kvm has to be tagged with a sequential id that incremented every allocation. This id can be checked here. > + > + return true; > +} -- Kirill A. Shutemov