From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 1/2] KVM: x86 emulator: don't update vcpu state if instruction is restarted. Date: Sun, 01 Aug 2010 11:54:38 +0300 Message-ID: <4C55364E.9090605@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> <20100801082815.GC24773@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: mtosatti@redhat.com, kvm@vger.kernel.org To: Gleb Natapov Return-path: Received: from mx1.redhat.com ([209.132.183.28]:14671 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753186Ab0HAIyk (ORCPT ); Sun, 1 Aug 2010 04:54:40 -0400 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o718sejY018560 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Sun, 1 Aug 2010 04:54:40 -0400 Received: from cleopatra.tlv.redhat.com (cleopatra.tlv.redhat.com [10.35.255.11]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o718sdj0024203 for ; Sun, 1 Aug 2010 04:54:39 -0400 In-Reply-To: <20100801082815.GC24773@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 08/01/2010 11:28 AM, Gleb Natapov wrote: > 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. But non-emulated pio does a skip_emulated_instruction() immediately (or so the code in kvm-tpr-opt.c assumes: > static void vtpr_ioport_write(void *opaque, uint32_t addr, uint32_t val) > { > CPUState *env = cpu_single_env; > uint32_t rip; > > cpu_synchronize_state(env); > > rip = env->eip - 2; > write_byte_virt(env, rip, 0x66); > write_byte_virt(env, rip + 1, 0x90); ) -- error compiling committee.c: too many arguments to function