From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Graf Subject: Re: [PATCH] kvm-pr: manage illegal instructions Date: Wed, 11 May 2016 12:35:42 +0200 Message-ID: <57330AFE.1050209@suse.de> References: <1458073117-24652-1-git-send-email-lvivier@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: Michael Ellerman , Benjamin Herrenschmidt , Gleb Natapov , linuxppc-dev@lists.ozlabs.org, Paolo Bonzini , Paul Mackerras , linux-kernel@vger.kernel.org To: Laurent Vivier , kvm@vger.kernel.org, kvm-ppc@vger.kernel.org Return-path: In-Reply-To: <1458073117-24652-1-git-send-email-lvivier@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.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