Re: [PATCH 0/8] RFC: Pass tests for x86_64 machine types compiled individually

[Thomas Huth]

On 02/09/2022 19.34, Juan Quintela wrote:
[...]
> There are interesting cases, and are the tests are run with the
> default machine type (pc) but that work with either of them
[...]
> This tests can be run with both machine types, but as we can't easily
> put -machine on them (several of them are supposed to run on other
> architectures), it is not "trivial to fix".  I have a "hack" on my
> tree that gets the 1st machine available for this kind of tests and
> changed qtest_init() to qtest_init_first() that does exactly that.
> But I am not sure that is the way to go.

I don't think that this would be a reliable solution, e.g. with 
qemu-system-ppc64 or -aarch64, there are plenty of different machine types 
and you cannot simply grab the first one to hope that it is good enough to 
run the tests.

> Another way for me to fix it
> is just to change the Q35 machine to be the default for x86_64 when
> I400FX is not compiled in, but it has other kind of troubles.

I think there was a consensus in the past to rather get away from default 
machine types, so I think that's also the wrong way to go.

> I
> started this wanting than all tests showed an explicit machine type,
> but there is nothing easier to be done for this multiarch tests.

What about this idea: Introduce a "qtest_default_machine()" function that 
looks like this:

const char *qtest_default_machine(void)
{
    if (g_strequal(arch, "i386") || g_strequal(arch, "x86_64")) {
        if (qtest_has_machine("pc")) {
            return "-machine pc";
        } else if (qtest_has_machine("q35")) {
            return "-machine q35";
        } else {
            abort(); // Or skip the test somehow?
        }
    }

    if (g_strequal(arch, "arm") || g_strequal(arch, "aarch64")) {
        /* ARM does not have a default machine, so use "virt" */
        if (qtest_has_machine("virt")) {
            return "-machine virt";
        } else {
            abort(); // Or skip the test somehow?
        }

    // ... similar logic for m68k, riscv, rx, avr and tricore ...

    /* For all others use the default machine */
    return "";
}

Then you could use this à la:

    qts = qtest_init("%s ...", gtest_default_machine(), ...);

Or even add a wrapper function qtest_init_default_machine() for this?

 HTH,
  Thomas