Re: [Qemu-ppc] [Qemu-devel] [RFC PATCH] tests/device-introspect: Test devices with all machines, not only with "none"

[Markus Armbruster]

Eduardo Habkost <address@hidden> writes:

> On Fri, Apr 27, 2018 at 08:31:58AM +0200, Markus Armbruster wrote:
>> Eduardo Habkost <address@hidden> writes:
>> 
>> > On Thu, Apr 26, 2018 at 05:20:25PM +0200, Thomas Huth wrote:
>> >> On 26.04.2018 13:45, Markus Armbruster wrote:
>> >> > Thomas Huth <address@hidden> writes:
>> >> [...]
>> >> >> @@ -260,6 +263,26 @@ static void test_abstract_interfaces(void)
>> >> >>      qtest_end();
>> >> >>  }
>> >> >>  
>> >> >> +static void add_machine_test_case(const char *mname)
>> >> >> +{
>> >> >> +    char *path, *args;
>> >> >> +
>> >> >> +    /* Ignore blacklisted machines */
>> >> >> +    if (g_str_equal("xenfv", mname) || g_str_equal("xenpv", mname)) {
>> >> >> +        return;
>> >> >> +    }
>> >> >> +
>> >> >> +    path = g_strdup_printf("device/introspect/concrete-defaults-%s", 
>> >> >> mname);
>> >> >> +    args = g_strdup_printf("-machine %s", mname);
>> >> >> +    qtest_add_data_func(path, args, test_device_intro_concrete);
>> >> > 
>> >> > This runs test_device_intro_concrete() with "-machine M" for all machine
>> >> > types M, in SPEED=slow mode.
>> >> > 
>> >> >> +    g_free(path);
>> >> >> +
>> >> >> +    path = 
>> >> >> g_strdup_printf("device/introspect/concrete-nodefaults-%s", mname);
>> >> >> +    args = g_strdup_printf("-nodefaults -machine %s", mname);
>> >> >> +    qtest_add_data_func(path, args, test_device_intro_concrete);
>> >> > 
>> >> > This runs test_device_intro_concrete() with "-nodefaults -machine M" for
>> >> > all machine types M, in SPEED=slow mode.
>> >> > 
>> >> > Has "without -nodefaults" exposed additional bugs?
>> >> 
>> >> After testing this with all machines, I had to discover that
>> >> "-nodefaults" does not work so easily: A lot of the embedded machines
>> >> (especially the ARM machines) simply refuse to work with "-nodefaults"
>> >> and exit immediately instead. E.g.:
>> >> 
>> >> $ arm-softmmu/qemu-system-arm -nodefaults -nographic -M n810,accel=qtest
>> >> qemu-system-arm: missing SecureDigital device
>> 
>> These are all bugs.  --nodefaults is supposed to suppress *optional*
>> devices, not mandatory ones.
>
> I'm not sure I understand the requirements.  What exactly is the
> definition of "mandatory"?
>
> A machine created by "qemu-system-x86_64 -machine pc -nodefaults"
> is useless because it has no any device to boot from.  How is
> that different from a n810 machine not booting because there's no
> SD device?

I propose:

* Stuff that's required for QEMU to run is not suppressed by -nodefaults

* Stuff that a real machine has soldered on is also not suppressed

* Stuff that can be pulled out of a real machine may be suppressed, even
  when that means the guest won't run

Does that make some sense?