From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752098AbcEKKfu (ORCPT ); Wed, 11 May 2016 06:35:50 -0400 Received: from mx2.suse.de ([195.135.220.15]:32884 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751395AbcEKKfs (ORCPT ); Wed, 11 May 2016 06:35:48 -0400 Subject: Re: [PATCH] kvm-pr: manage illegal instructions To: Laurent Vivier , kvm@vger.kernel.org, kvm-ppc@vger.kernel.org References: <1458073117-24652-1-git-send-email-lvivier@redhat.com> Cc: Michael Ellerman , Benjamin Herrenschmidt , Gleb Natapov , linuxppc-dev@lists.ozlabs.org, Paolo Bonzini , Paul Mackerras , linux-kernel@vger.kernel.org From: Alexander Graf Message-ID: <57330AFE.1050209@suse.de> Date: Wed, 11 May 2016 12:35:42 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <1458073117-24652-1-git-send-email-lvivier@redhat.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/15/2016 09:18 PM, Laurent Vivier wrote: > While writing some instruction tests for kvm-unit-tests for powerpc, > I've found that illegal instructions are not managed correctly with kvm-pr, > while it is fine with kvm-hv. > > When an illegal instruction (like ".long 0") is processed by kvm-pr, > the kernel logs are filled with: > > Couldn't emulate instruction 0x00000000 (op 0 xop 0) > kvmppc_handle_exit_pr: emulation at 700 failed (00000000) > > While the exception handler receives an interrupt for each instruction > executed after the illegal instruction. > > Signed-off-by: Laurent Vivier > --- > arch/powerpc/kvm/book3s_emulate.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/arch/powerpc/kvm/book3s_emulate.c b/arch/powerpc/kvm/book3s_emulate.c > index 2afdb9c..4ee969d 100644 > --- a/arch/powerpc/kvm/book3s_emulate.c > +++ b/arch/powerpc/kvm/book3s_emulate.c > @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct kvm_vcpu *vcpu, > > switch (get_op(inst)) { > case 0: > - emulated = EMULATE_FAIL; > if ((kvmppc_get_msr(vcpu) & MSR_LE) && > (inst == swab32(inst_sc))) { > /* > @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct kvm_vcpu *vcpu, > kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED); > kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4); > emulated = EMULATE_DONE; > + } else { > + kvmppc_core_queue_program(vcpu, SRR1_PROGILL); But isn't that exactly what the semantic of EMULATE_FAIL is? Fixing it up in book3s_emulate.c is definitely the wrong spot. So what is the problem you're trying to solve? Is the SRR0 at the wrong spot or are the log messages the problem? Alex