From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: Re: [patch 3/4] KVM: MMU: reload request from GET_DIRTY_LOG path Date: Tue, 9 Sep 2014 12:28:11 -0300 Message-ID: <20140909152811.GA4153@amt.cnet> References: <20140709191250.408928362@amt.cnet> <20140709191611.280800634@amt.cnet> <20140721131424.GZ18167@minantech.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org, ak@linux.intel.com, pbonzini@redhat.com, xiaoguangrong@linux.vnet.ibm.com, avi.kivity@gmail.com To: Gleb Natapov Return-path: Received: from mx1.redhat.com ([209.132.183.28]:45546 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753801AbaIIPl4 (ORCPT ); Tue, 9 Sep 2014 11:41:56 -0400 Content-Disposition: inline In-Reply-To: <20140721131424.GZ18167@minantech.com> Sender: kvm-owner@vger.kernel.org List-ID: On Mon, Jul 21, 2014 at 04:14:24PM +0300, Gleb Natapov wrote: > On Wed, Jul 09, 2014 at 04:12:53PM -0300, mtosatti@redhat.com wrote: > > Reload remote vcpus MMU from GET_DIRTY_LOG codepath, before > > deleting a pinned spte. > > > > Signed-off-by: Marcelo Tosatti > > > > --- > > arch/x86/kvm/mmu.c | 29 +++++++++++++++++++++++------ > > 1 file changed, 23 insertions(+), 6 deletions(-) > > > > Index: kvm.pinned-sptes/arch/x86/kvm/mmu.c > > =================================================================== > > --- kvm.pinned-sptes.orig/arch/x86/kvm/mmu.c 2014-07-09 11:23:59.290744490 -0300 > > +++ kvm.pinned-sptes/arch/x86/kvm/mmu.c 2014-07-09 11:24:58.449632435 -0300 > > @@ -1208,7 +1208,8 @@ > > * > > * Return true if tlb need be flushed. > > */ > > -static bool spte_write_protect(struct kvm *kvm, u64 *sptep, bool pt_protect) > > +static bool spte_write_protect(struct kvm *kvm, u64 *sptep, bool pt_protect, > > + bool skip_pinned) > > { > > u64 spte = *sptep; > > > > @@ -1218,6 +1219,22 @@ > > > > rmap_printk("rmap_write_protect: spte %p %llx\n", sptep, *sptep); > > > > + if (is_pinned_spte(spte)) { > > + /* keep pinned spte intact, mark page dirty again */ > > + if (skip_pinned) { > > + struct kvm_mmu_page *sp; > > + gfn_t gfn; > > + > > + sp = page_header(__pa(sptep)); > > + gfn = kvm_mmu_page_get_gfn(sp, sptep - sp->spt); > > + > > + mark_page_dirty(kvm, gfn); > > + return false; > Why not mark all pinned gfns as dirty in kvm_vm_ioctl_get_dirty_log() while > populating dirty_bitmap_buffer? The pinned gfns are per-vcpu. Requires looping all vcpus (not scalable). > > + } else > > + mmu_reload_pinned_vcpus(kvm); > Can you explain why do you need this? Because if skip_pinned = false, we want vcpus to exit (called from enable dirty logging codepath).