Re: [Qemu-devel] QEMU postcopy-test failing on ppc64

[Laurent Vivier]

On 15/11/2016 20:00, Eric Blake wrote:
> On 11/15/2016 12:48 PM, Thomas Huth wrote:
> 
>>> Even for Power, I'd prefer to keep KVM since the problem only happens with
>>> KVM PR which isn't the preferred way to do KVM on bare metal... until this
>>> get fixed, I'd rather suggest people to run make check with KVM HV.
>>
>> OK ... what do you think about a patch like this:
>>
>> diff --git a/tests/postcopy-test.c b/tests/postcopy-test.c
>> --- a/tests/postcopy-test.c
>> +++ b/tests/postcopy-test.c
>> @@ -380,17 +380,19 @@ static void test_migrate(void)
>>                                    " -incoming %s",
>>                                    tmpfs, bootpath, uri);
>>      } else if (strcmp(arch, "ppc64") == 0) {
>> +        const char *accel;
>>          init_bootfile_ppc(bootpath);
>> -        cmd_src = g_strdup_printf("-machine accel=kvm:tcg -m 256M"
>> +        accel = system("/sbin/lsmod | grep -q kvm_hv") ? "tcg" : "kvm:tcg";
> 
> Unsafe use of system() (all I have to do is stick a counterfeit 'grep'
> earlier on my PATH to mess you up). Is there a safer way to grab that
> information without having to call out to the shell?

I think trying to open "/dev/kvm" would be enough to know if kvm is
available or not.

Laurent