From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752735Ab3F0JOa (ORCPT ); Thu, 27 Jun 2013 05:14:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33665 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752069Ab3F0JO2 (ORCPT ); Thu, 27 Jun 2013 05:14:28 -0400 Date: Thu, 27 Jun 2013 12:14:24 +0300 From: Gleb Natapov To: Xiao Guangrong Cc: avi.kivity@gmail.com, mtosatti@redhat.com, pbonzini@redhat.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Subject: Re: [PATCH v3 4/6] KVM: MMU: fast invalidate all mmio sptes Message-ID: <20130627091424.GA10758@redhat.com> References: <1370595088-3315-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com> <1370595088-3315-5-git-send-email-xiaoguangrong@linux.vnet.ibm.com> <20130627082900.GD18508@redhat.com> <20130627090110.GE18508@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130627090110.GE18508@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 27, 2013 at 12:01:10PM +0300, Gleb Natapov wrote: > On Thu, Jun 27, 2013 at 11:29:00AM +0300, Gleb Natapov wrote: > > On Fri, Jun 07, 2013 at 04:51:26PM +0800, Xiao Guangrong wrote: > > > This patch tries to introduce a very simple and scale way to invalidate > > > all mmio sptes - it need not walk any shadow pages and hold mmu-lock > > > > > > KVM maintains a global mmio valid generation-number which is stored in > > > kvm->memslots.generation and every mmio spte stores the current global > > > generation-number into his available bits when it is created > > > > > > When KVM need zap all mmio sptes, it just simply increase the global > > > generation-number. When guests do mmio access, KVM intercepts a MMIO #PF > > > then it walks the shadow page table and get the mmio spte. If the > > > generation-number on the spte does not equal the global generation-number, > > > it will go to the normal #PF handler to update the mmio spte > > > > > > Since 19 bits are used to store generation-number on mmio spte, we zap all > > > mmio sptes when the number is round > > > > > So this commit makes Fedora 9 32 bit reboot during boot, Fedora 9 64 > > fails too, but I haven't checked what happens exactly. > > > Something wrong with gfn calculation during mmio: > > qemu-system-x86-17003 [000] 3962.625103: handle_mmio_page_fault: addr:c00ba6c0 gfn 100000000ba access a92 > qemu-system-x86-17003 [000] 3962.774862: handle_mmio_page_fault: addr:ffffb170 gfn 100000fee00 access a92 > Hmm, so I wounder why get_mmio_spte_gfn() does not clear gen bits. -- Gleb.