Re: [PATCH] kvm-unit-tests : The first version of VMX nested test case

Gleb Natapov
2013-07-16T16:45:23Z

On Tue, Jul 16, 2013 at 11:29:20PM +0800, Arthur Chunqi Li wrote:
> On Tue, Jul 16, 2013 at 11:20 PM, Gleb Natapov <gleb@redhat.com> wrote:
> > On Tue, Jul 16, 2013 at 12:28:05PM +0200, Paolo Bonzini wrote:
> >> > +void vmx_exit(void)
> >> > +{
> >> > + test_vmxoff();
> >> > + printf("\nSUMMARY: %d tests, %d failures\n", tests, fails);
> >> > + exit(fails ? -1 : 0);
> >> > +}
> >>
> >> Can you try to jump back to main, and do test_vmxoff there? This will
> >> avoid having to write our tests in callback style, which is a pain.
> >> Basically something similar to setjmp/longjmp. In main:
> >>
> >> if (setjmp(jmpbuf) == 0) {
> >> vmx_run();
> >> /* Should not reach here */
> >> report("test vmlaunch", 0);
> >> }
> >> test_vmxoff();
> >>
> >> exit:
> >> printf("\nSUMMARY: %d tests, %d failures\n", tests, fails);
> >> return fails ? 1 : 0;
> >>
> >> In vmx_handler:
> >>
> >> case VMX_HLT:
> >> printf("\nVM exit.\n");
> >> longjmp(jmpbuf, 1);
> >>
> > Why not just make vmexit occur after vmlaunch/vmresume like KVM does. It
> > will make code much more straightforward and easer to follow.
> The concept "easier to follow" may have different meanings in
> different view. This achievement puts all the test cases in main
> function instead of scattering everywhere, which is another view to
> "easy to follow". As this is just a test case, I prefer this one.
>
I do not see why what I propose will prevent you to put all tests into main.

vmx_run() will looks like that:

vmlaunch
while(1) {
vmresume
<---- vmexit jumps here
switch(exit reason) {
case reason1:
break;
case reason2:
break;
case HLT
return;
}
}

> Besides, this way we can start another VM following the previous one
> simply in main function. This is flexible if we want to test re-enter
> to VMX mode or so.
>
That's what I am missing. How do one writes more tests now?

I was thinking about interface like that:

guest_func_test1()
{
}

tes1t_exit_handlers[] = {test1_handle_hlt, test1_handle_exception, ....}

main()
{

init_vmcs(); /* generic stuff */
init_vmcs_test1(); /* test1 related stuff */
r = run_in_guest(guest_func_test1, test1_exit_handlers);
report("test1", r);
}

--
Gleb.