Re: [PATCH] kvm-pr: manage illegal instructions

From: Thomas Huth
Date: Mon May 09 2016 - 04:14:52 EST


On 21.04.2016 11:25, Thomas Huth wrote:
> On 15.03.2016 21:18, 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 <lvivier@xxxxxxxxxx>
>> ---
>> 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);
>> + emulated = EMULATE_AGAIN;
>> }
>> break;
>> case 19:
>>
>
> Tested-by: Thomas Huth <thuth@xxxxxxxxxx>

Ping!

Alex, Paul, could you please pick up this patch? This patch is required
to get the kvm-unit-tests working properly with kvm-pr, so I'd be glad
if we could get this included finally...

Thanks,
Thomas