From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751996Ab3FJH5C (ORCPT ); Mon, 10 Jun 2013 03:57:02 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56728 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751117Ab3FJH5A (ORCPT ); Mon, 10 Jun 2013 03:57:00 -0400 Date: Mon, 10 Jun 2013 10:56:56 +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 0/6] KVM: MMU: fast invalidate all mmio sptes Message-ID: <20130610075656.GY4725@redhat.com> References: <1370595088-3315-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1370595088-3315-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 07, 2013 at 04:51:22PM +0800, Xiao Guangrong wrote: > Changelog: > V3: > All of these changes are from Gleb's review: > 1) rename RET_MMIO_PF_EMU to RET_MMIO_PF_EMULATE. > 2) smartly adjust kvm generation number in kvm_current_mmio_generatio() > to avoid kvm_memslots->generation overflow. > > V2: > - rename kvm_mmu_invalid_mmio_spte to kvm_mmu_invalid_mmio_sptes > - use kvm->memslots->generation as kvm global generation-number > - fix comment and codestyle > - init kvm generation close to mmio wrap-around value > - keep kvm_mmu_zap_mmio_sptes > > The current way is holding hot mmu-lock and walking all shadow pages, this > is not scale. This patchset tries to introduce a very simple and scale way > to fast invalidate all mmio sptes - it need not walk any shadow pages and hold > any locks. > > The idea is simple: > 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 > Looks good to me, but doesn't tis obsolete kvm_mmu_zap_mmio_sptes() and sp->mmio_cached, so they should be removed as part of the patch series? > Xiao Guangrong (6): > KVM: MMU: retain more available bits on mmio spte > KVM: MMU: store generation-number into mmio spte > KVM: MMU: make return value of mmio page fault handler more readable > KVM: MMU: fast invalidate all mmio sptes > KVM: MMU: add tracepoint for check_mmio_spte > KVM: MMU: init kvm generation close to mmio wrap-around value > > arch/x86/include/asm/kvm_host.h | 2 +- > arch/x86/kvm/mmu.c | 131 ++++++++++++++++++++++++++++++++-------- > arch/x86/kvm/mmu.h | 17 ++++++ > arch/x86/kvm/mmutrace.h | 34 +++++++++-- > arch/x86/kvm/paging_tmpl.h | 10 ++- > arch/x86/kvm/vmx.c | 12 ++-- > arch/x86/kvm/x86.c | 11 +++- > 7 files changed, 177 insertions(+), 40 deletions(-) > > -- > 1.8.1.4 -- Gleb.