From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 00484C34047 for ; Wed, 19 Feb 2020 15:17:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D1FD224670 for ; Wed, 19 Feb 2020 15:17:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726858AbgBSPRI (ORCPT ); Wed, 19 Feb 2020 10:17:08 -0500 Received: from mga17.intel.com ([192.55.52.151]:11100 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726683AbgBSPRI (ORCPT ); Wed, 19 Feb 2020 10:17:08 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 19 Feb 2020 07:16:45 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,459,1574150400"; d="scan'208";a="258945868" Received: from sjchrist-coffee.jf.intel.com (HELO linux.intel.com) ([10.54.74.202]) by fmsmga004.fm.intel.com with ESMTP; 19 Feb 2020 07:16:44 -0800 Date: Wed, 19 Feb 2020 07:16:44 -0800 From: Sean Christopherson To: Paolo Bonzini Cc: Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 3/3] KVM: x86: Move #PF retry tracking variables into emulation context Message-ID: <20200219151644.GB15888@linux.intel.com> References: <20200218230310.29410-1-sean.j.christopherson@intel.com> <20200218230310.29410-4-sean.j.christopherson@intel.com> <40c8d560-1a5d-d592-5682-720980ca3dd9@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <40c8d560-1a5d-d592-5682-720980ca3dd9@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 19, 2020 at 09:13:00AM +0100, Paolo Bonzini wrote: > On 19/02/20 00:03, Sean Christopherson wrote: > > Move last_retry_eip and last_retry_addr into the emulation context as > > they are specific to retrying an instruction after emulation failure. > > > > Signed-off-by: Sean Christopherson > > I'm not sure about this, since it's not used by emulate.c. The other > two patches are good. The easy solution to that is to move retry_instruction() into emulate.c. That would also allow making x86_page_table_writing_insn() static. All other functions invoked from retry_instruction() are exposed via kvm_host.h. Moving last_retry_* into the emulator context hopefully makes it more clear that this code is the only user of the variables, e.g. last_retry_eip can't be set by some other non-emulator flow. if (ctxt->eip == last_retry_eip && last_retry_addr == cr2) return false; vcpu->arch.last_retry_eip = ctxt->eip; vcpu->arch.last_retry_addr = cr2; > > --- > > arch/x86/include/asm/kvm_emulate.h | 4 ++++ > > arch/x86/include/asm/kvm_host.h | 3 --- > > arch/x86/kvm/x86.c | 11 ++++++----- > > 3 files changed, 10 insertions(+), 8 deletions(-) > > > > diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h > > index a4ef19a6e612..a26c8de414e8 100644 > > --- a/arch/x86/include/asm/kvm_emulate.h > > +++ b/arch/x86/include/asm/kvm_emulate.h > > @@ -315,6 +315,10 @@ struct x86_emulate_ctxt { > > bool gpa_available; > > gpa_t gpa_val; > > > > + /* Track EIP and CR2/GPA when retrying faulting instruction on #PF. */ > > + unsigned long last_retry_eip; > > + unsigned long last_retry_addr; > > + > > /* > > * decode cache > > */ > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > > index 9c79c41eb5f6..6312ea32bb41 100644 > > --- a/arch/x86/include/asm/kvm_host.h > > +++ b/arch/x86/include/asm/kvm_host.h > > @@ -752,9 +752,6 @@ struct kvm_vcpu_arch { > > > > cpumask_var_t wbinvd_dirty_mask; > > > > - unsigned long last_retry_eip; > > - unsigned long last_retry_addr; > > - > > struct { > > bool halted; > > gfn_t gfns[roundup_pow_of_two(ASYNC_PF_PER_VCPU)]; > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > > index f88b72932c35..d19eb776f297 100644 > > --- a/arch/x86/kvm/x86.c > > +++ b/arch/x86/kvm/x86.c > > @@ -6407,6 +6407,7 @@ static void init_emulate_ctxt(struct kvm_vcpu *vcpu) > > > > kvm_x86_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l); > > > > + /* last_retry_{eip,addr} are persistent and must not be init'd here. */ > > ctxt->gpa_available = false; > > ctxt->eflags = kvm_get_rflags(vcpu); > > ctxt->tf = (ctxt->eflags & X86_EFLAGS_TF) != 0; > > @@ -6557,8 +6558,8 @@ static bool retry_instruction(struct x86_emulate_ctxt *ctxt, > > struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt); > > unsigned long last_retry_eip, last_retry_addr, gpa = cr2_or_gpa; > > > > - last_retry_eip = vcpu->arch.last_retry_eip; > > - last_retry_addr = vcpu->arch.last_retry_addr; > > + last_retry_eip = ctxt->last_retry_eip; > > + last_retry_addr = ctxt->last_retry_addr; > > > > /* > > * If the emulation is caused by #PF and it is non-page_table > > @@ -6573,7 +6574,7 @@ static bool retry_instruction(struct x86_emulate_ctxt *ctxt, > > * and the address again, we can break out of the potential infinite > > * loop. > > */ > > - vcpu->arch.last_retry_eip = vcpu->arch.last_retry_addr = 0; > > + ctxt->last_retry_eip = ctxt->last_retry_addr = 0; > > > > if (!(emulation_type & EMULTYPE_ALLOW_RETRY_PF)) > > return false; > > @@ -6588,8 +6589,8 @@ static bool retry_instruction(struct x86_emulate_ctxt *ctxt, > > if (ctxt->eip == last_retry_eip && last_retry_addr == cr2_or_gpa) > > return false; > > > > - vcpu->arch.last_retry_eip = ctxt->eip; > > - vcpu->arch.last_retry_addr = cr2_or_gpa; > > + ctxt->last_retry_eip = ctxt->eip; > > + ctxt->last_retry_addr = cr2_or_gpa; > > > > if (!vcpu->arch.mmu->direct_map) > > gpa = kvm_mmu_gva_to_gpa_write(vcpu, cr2_or_gpa, NULL); > > >