From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: [PATCH 2/2] x86: Bail out on unemulated instructions Date: Sun, 15 Aug 2010 10:32:36 +0300 Message-ID: <20100815073236.GP10499@redhat.com> References: <1281801094-4515-1-git-send-email-m.gamal005@gmail.com> <1281801094-4515-2-git-send-email-m.gamal005@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: avi@redhat.com, mtosatti@redhat.com, kvm@vger.kernel.org To: Mohammed Gamal Return-path: Received: from mx1.redhat.com ([209.132.183.28]:44545 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758527Ab0HOQNR (ORCPT ); Sun, 15 Aug 2010 12:13:17 -0400 Content-Disposition: inline In-Reply-To: <1281801094-4515-2-git-send-email-m.gamal005@gmail.com> Sender: kvm-owner@vger.kernel.org List-ID: On Sat, Aug 14, 2010 at 06:51:34PM +0300, Mohammed Gamal wrote: > If emulation fails due to the instruction being unemulated. Return immediately > instead of restarting the instruction and infinitely trying to execute it. > This is already handled correctly as far as I can see. Sometimes instruction should be retried and reexecute_instruction() checks for that case. If instruction emulation fails in big real mode re-executing instruction will be useless though, so what should be done is to make reexecute_instruction() return false if vcpu is in big real mode and cpu relies on emulation to handle it. > Signed-off-by: Mohammed Gamal > --- > arch/x86/kvm/x86.c | 6 ++++++ > 1 files changed, 6 insertions(+), 0 deletions(-) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 416aa0e..a31db44 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -4036,6 +4036,9 @@ int emulate_instruction(struct kvm_vcpu *vcpu, > } > > ++vcpu->stat.insn_emulation; > + if (r == X86EMUL_UNHANDLEABLE) > + return handle_emulation_failure(vcpu); > + > if (r) { > if (reexecute_instruction(vcpu, cr2)) > return EMULATE_DONE; > @@ -4057,6 +4060,9 @@ int emulate_instruction(struct kvm_vcpu *vcpu, > restart: > r = x86_emulate_insn(&vcpu->arch.emulate_ctxt); > > + if (r == X86EMUL_UNHANDLEABLE) > + return handle_emulation_failure(vcpu); > + > if (r) { /* emulation failed */ > if (reexecute_instruction(vcpu, cr2)) > return EMULATE_DONE; > -- > 1.7.0.4 > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Gleb.