On 19/05/2016 10:07, Thomas Huth wrote: > On 19.05.2016 09:58, Laurent Vivier wrote: >> >> >> On 18/05/2016 21:01, Thomas Huth wrote: >>> If kvmppc_handle_exit_pr() calls kvmppc_emulate_instruction() to emulate >>> one instruction (in the BOOK3S_INTERRUPT_H_EMUL_ASSIST case), it calls >>> kvmppc_core_queue_program() afterwards if kvmppc_emulate_instruction() >>> returned EMULATE_FAIL, so the guest gets an program interrupt for the >>> illegal opcode. >>> However, the kvmppc_emulate_instruction() also tried to inject a >>> program exception for this already, so the program interrupt gets >>> injected twice and the return address in srr0 gets destroyed. >>> All other callers of kvmppc_emulate_instruction() are also injecting >>> a program interrupt, and since the callers have the right knowledge >>> about the srr1 flags that should be used, it is the function >>> kvmppc_emulate_instruction() that should _not_ inject program >>> interrupts, so remove the kvmppc_core_queue_program() here. >>> >>> This fixes the issue discovered by Laurent Vivier with kvm-unit-tests >>> where the logs are filled with these messages when the test tries >>> to execute an illegal instruction: >>> >>> Couldn't emulate instruction 0x00000000 (op 0 xop 0) >>> kvmppc_handle_exit_pr: emulation at 700 failed (00000000) >>> >>> Signed-off-by: Thomas Huth <thuth@xxxxxxxxxx> >>> --- >>> arch/powerpc/kvm/emulate.c | 1 - >>> 1 file changed, 1 deletion(-) >>> >>> diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c >>> index 5cc2e7a..b379146 100644 >>> --- a/arch/powerpc/kvm/emulate.c >>> +++ b/arch/powerpc/kvm/emulate.c >>> @@ -302,7 +302,6 @@ int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu) >>> advance = 0; >>> printk(KERN_ERR "Couldn't emulate instruction 0x%08x " >>> "(op %d xop %d)\n", inst, get_op(inst), get_xop(inst)); >>> - kvmppc_core_queue_program(vcpu, 0); >>> } >>> } >>> >>> >> >> I've tested this patch with kvm-unit-tests: it solves the multiple >> illegal instruction exceptions, but the test fails because SRR1 is not >> updated correctly. It should contains the bit for "Illegal Instruction" >> whereas it is 0. >> [But I think it's what you explain in your last email] > > Yes, but that's a separate problem, so I did not include it in this > patch here yet. (Also, I'm not sure yet how to exactly fix that other > problem with SRR1) OK, so for this one I can say: Tested-by: Laurent Vivier <lvivier@xxxxxxxxxx> Laurent -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
