From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linutronix.de (193.142.43.55:993) by crypto-ml.lab.linutronix.de with IMAP4-SSL for ; 10 Oct 2019 16:14:21 -0000 Received: from us-smtp-2.mimecast.com ([207.211.31.81] helo=us-smtp-delivery-1.mimecast.com) by Galois.linutronix.de with esmtps (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1iIb51-0005Dp-Rl for speck@linutronix.de; Thu, 10 Oct 2019 18:14:20 +0200 Received: by mail-wr1-f70.google.com with SMTP id j7so2976565wrx.14 for ; Thu, 10 Oct 2019 09:14:15 -0700 (PDT) Received: from ?IPv6:2001:b07:6468:f312:ddc7:c53c:581a:7f3e? ([2001:b07:6468:f312:ddc7:c53c:581a:7f3e]) by smtp.gmail.com with ESMTPSA id l13sm6722713wmj.25.2019.10.10.09.14.13 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 10 Oct 2019 09:14:13 -0700 (PDT) Subject: [MODERATED] Re: [PATCH v5 8/8] NX 8 References: <1561989149-17323-1-git-send-email-pbonzini@redhat.com> <1561989149-17323-9-git-send-email-pbonzini@redhat.com> <8eab605b-df0e-74d0-e448-986149edf33e@redhat.com> <20191002203850.GA26522@guptapadev.amr> <7834bcbb-fbc1-2d57-bf3c-955d5169fe87@redhat.com> <20191007194555.GD5154@guptapadev.amr> <20191009144147.GC11840@guptapadev.amr> <3437a345-bc77-b43e-3b1b-1ae3961da70b@redhat.com> <20191010055343.GG11840@guptapadev.amr> From: Paolo Bonzini Message-ID: <0c9644ff-f0e1-66bd-551f-9534e3d6737e@redhat.com> Date: Thu, 10 Oct 2019 18:14:12 +0200 MIME-Version: 1.0 In-Reply-To: <20191010055343.GG11840@guptapadev.amr> Content-Type: multipart/mixed; boundary="gizhYbulz8ng8TEllDnikaTUDCzG4hMPm"; protected-headers="v1" To: speck@linutronix.de List-ID: This is an OpenPGP/MIME encrypted message (RFC 4880 and 3156) --gizhYbulz8ng8TEllDnikaTUDCzG4hMPm Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 10/10/19 07:53, speck for Pawan Gupta wrote: > On Wed, Oct 09, 2019 at 05:10:44PM +0200, speck for Paolo Bonzini wrote= : >> On 09/10/19 16:41, speck for Pawan Gupta wrote: >>> On Wed, Oct 09, 2019 at 08:13:49AM +0200, speck for Paolo Bonzini wro= te: >>>> On 07/10/19 21:45, speck for Pawan Gupta wrote: >>>>>> Yes, I have other small changes I made so I'll send it out soon to= gether >>>>>> with a list of preparatory patches that were committed in the past= months. >>>>> Just wanted to add that we would also need to do the backporting an= d >>>>> testing soon. >>>> >>>> Sure. With the full list of required patches it shouldn't be an iss= ue. >>> >>> When do you think you can post a v6? >> >> I have gotten a report of a crash, I'm trying to understand if it's my= >> patches or something pre-existing. I believe it's the latter, but I'd= >> rather be sure. I can post v6 right now though. >=20 > We can help debug the crash. Can you please share the series, > reproduction steps and the crash signature. The reproduction steps for v5 are as follows: - grab the next branch of kvm-unit-tests.git[1] and build it - create a lot of hugepages, on my machine I use 40 GiB worth of them: echo 20480 > /proc/sys/vm/nr_hugepages - load KVM with kvm.nx_huge_pages_recovery_period_secs=3D3 - run the following script while true; do echo N > /sys/module/kvm/parameters/nx_huge_pages; sleep 1 echo Y > /sys/module/kvm/parameters/nx_huge_pages; sleep 5 done - run the testcase with MEM=3D40960 # in megabytes qemu-kvm -nodefaults -vnc none -serial stdio -kernel x86/hugetext.flat -m $MEM -mem-path /dev/hugepages You can also add a WARN_ON_ONCE(!sp->lpage_disallowed) to kvm_recover_nx_lpages before the call to kvm_mmu_prepare_zap_page. As soon as it triggers, of course everything will go downhill. Paolo [1] git://git.kernel.org/pub/scm/virt/kvm/kvm-unit-tests.git --gizhYbulz8ng8TEllDnikaTUDCzG4hMPm--