From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: [PATCH 1/2] KVM: x86 emulator: don't update vcpu state if instruction is restarted. Date: Sun, 1 Aug 2010 11:28:15 +0300 Message-ID: <20100801082815.GC24773@redhat.com> References: <1280405513-579-1-git-send-email-gleb@redhat.com> <1280405513-579-2-git-send-email-gleb@redhat.com> <4C545C79.1010102@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: mtosatti@redhat.com, kvm@vger.kernel.org To: Avi Kivity Return-path: Received: from mx1.redhat.com ([209.132.183.28]:4136 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752125Ab0HAI2R (ORCPT ); Sun, 1 Aug 2010 04:28:17 -0400 Received: from int-mx08.intmail.prod.int.phx2.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o718SG00014487 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Sun, 1 Aug 2010 04:28:17 -0400 Content-Disposition: inline In-Reply-To: <4C545C79.1010102@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Sat, Jul 31, 2010 at 08:25:13PM +0300, Avi Kivity wrote: > On 07/29/2010 03:11 PM, Gleb Natapov wrote: > >No need to update vcpu state since instruction is in the middle of the > >emulation. > > > >Signed-off-by: Gleb Natapov > >--- > > arch/x86/kvm/x86.c | 31 +++++++++++++------------------ > > 1 files changed, 13 insertions(+), 18 deletions(-) > > > >diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > >index 76fbc32..7e5f075 100644 > >--- a/arch/x86/kvm/x86.c > >+++ b/arch/x86/kvm/x86.c > >@@ -4057,32 +4057,27 @@ restart: > > return handle_emulation_failure(vcpu); > > } > > > >- toggle_interruptibility(vcpu, vcpu->arch.emulate_ctxt.interruptibility); > >- kvm_x86_ops->set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags); > >- memcpy(vcpu->arch.regs, c->regs, sizeof c->regs); > >- kvm_rip_write(vcpu, vcpu->arch.emulate_ctxt.eip); > >+ r = EMULATE_DONE; > > > >- if (vcpu->arch.emulate_ctxt.exception>= 0) { > >+ if (vcpu->arch.emulate_ctxt.exception>= 0) > > inject_emulated_exception(vcpu); > >- return EMULATE_DONE; > >- } > >- > >- if (vcpu->arch.pio.count) { > >+ else if (vcpu->arch.pio.count) { > > if (!vcpu->arch.pio.in) > > vcpu->arch.pio.count = 0; > >- return EMULATE_DO_MMIO; > >- } > >- > >- if (vcpu->mmio_needed) { > >+ r = EMULATE_DO_MMIO; > >+ } else if (vcpu->mmio_needed) { > > if (vcpu->mmio_is_write) > > vcpu->mmio_needed = 0; > >- return EMULATE_DO_MMIO; > >- } > >- > >- if (vcpu->arch.emulate_ctxt.restart) > >+ r = EMULATE_DO_MMIO; > >+ } else if (vcpu->arch.emulate_ctxt.restart) > > goto restart; > > > >- return EMULATE_DONE; > >+ toggle_interruptibility(vcpu, vcpu->arch.emulate_ctxt.interruptibility); > >+ kvm_x86_ops->set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags); > >+ memcpy(vcpu->arch.regs, c->regs, sizeof c->regs); > >+ kvm_rip_write(vcpu, vcpu->arch.emulate_ctxt.eip); > >+ > >+ return r; > > } > > EXPORT_SYMBOL_GPL(emulate_instruction); > > > > What about kvm-tpr-opt.c? It uses rip after pio. > It uses rip _during_ pio. And pio emulation changes rip only at the end of emulation. > It's true that it usually doesn't go through the emulator. > > -- > I have a truly marvellous patch that fixes the bug which this > signature is too narrow to contain. -- Gleb.