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 12:35:07 -0300 Message-ID: <20140909153507.GB4153@amt.cnet> References: <20140709191250.408928362@amt.cnet> <20140709191611.280800634@amt.cnet> <143ACAAF-5333-4D16-B9DD-46CFB75FBED1@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: kvm@vger.kernel.org, ak@linux.intel.com, pbonzini@redhat.com, gleb@kernel.org, avi.kivity@gmail.com To: Xiao Guangrong Return-path: Received: from mx1.redhat.com ([209.132.183.28]:15757 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753940AbaIIPlu (ORCPT ); Tue, 9 Sep 2014 11:41:50 -0400 Content-Disposition: inline In-Reply-To: <143ACAAF-5333-4D16-B9DD-46CFB75FBED1@linux.vnet.ibm.com> Sender: kvm-owner@vger.kernel.org List-ID: On Tue, Jul 22, 2014 at 05:55:20AM +0800, Xiao Guangrong wrote: >=20 > On Jul 10, 2014, at 3:12 AM, mtosatti@redhat.com wrote: >=20 > > Reload remote vcpus MMU from GET_DIRTY_LOG codepath, before > > deleting a pinned spte. > >=20 > > Signed-off-by: Marcelo Tosatti > >=20 > > --- > > arch/x86/kvm/mmu.c | 29 +++++++++++++++++++++++------ > > 1 file changed, 23 insertions(+), 6 deletions(-) > >=20 > > Index: kvm.pinned-sptes/arch/x86/kvm/mmu.c > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > --- kvm.pinned-sptes.orig/arch/x86/kvm/mmu.c 2014-07-09 11:23:59.29= 0744490 -0300 > > +++ kvm.pinned-sptes/arch/x86/kvm/mmu.c 2014-07-09 11:24:58.4496324= 35 -0300 > > @@ -1208,7 +1208,8 @@ > > * > > * Return true if tlb need be flushed. > > */ > > -static bool spte_write_protect(struct kvm *kvm, u64 *sptep, bool p= t_protect) > > +static bool spte_write_protect(struct kvm *kvm, u64 *sptep, bool p= t_protect, > > + bool skip_pinned) > > { > > u64 spte =3D *sptep; > >=20 > > @@ -1218,6 +1219,22 @@ > >=20 > > rmap_printk("rmap_write_protect: spte %p %llx\n", sptep, *sptep); > >=20 > > + 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 =3D page_header(__pa(sptep)); > > + gfn =3D kvm_mmu_page_get_gfn(sp, sptep - sp->spt); > > + > > + mark_page_dirty(kvm, gfn); > > + return false; > > + } else > > + mmu_reload_pinned_vcpus(kvm); > > + } > > + > > + > > if (pt_protect) > > spte &=3D ~SPTE_MMU_WRITEABLE; > > spte =3D spte & ~PT_WRITABLE_MASK; >=20 > This is also a window between marking spte readonly and re-ping=E2=80= =A6 > IIUC, I think all spte spte can not be zapped and write-protected at = any time It is safe because mmu_lock is held by kvm_mmu_slot_remove_write_access ?