Re: [kvm-unit-tests PATCH 01/14] x86: vm: allow multiple init for vm setup

[Peter Xu <peterx@redhat.com>]

On Thu, Oct 20, 2016 at 10:17:07AM +0200, Andrew Jones wrote:
> On Fri, Oct 14, 2016 at 08:40:39PM +0800, Peter Xu wrote:
> > Signed-off-by: Peter Xu <peterx@redhat.com>
> > ---
> >  lib/x86/vm.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> > 
> > diff --git a/lib/x86/vm.c b/lib/x86/vm.c
> > index 906fbf2..9771bd7 100644
> > --- a/lib/x86/vm.c
> > +++ b/lib/x86/vm.c
> > @@ -151,9 +151,16 @@ static void setup_mmu(unsigned long len)
> >  
> >  void setup_vm()
> >  {
> > +    static bool vm_inited = false;
> > +
> > +    if (vm_inited) {
> > +        return;
> > +    }
> > +
> >      end_of_memory = fwcfg_get_u64(FW_CFG_RAM_SIZE);
> >      free_memory(&edata, end_of_memory - (unsigned long)&edata);
> >      setup_mmu(end_of_memory);
> > +    vm_inited = true;
> >  }
> >  
> >  void *vmalloc(unsigned long size)
> > -- 
> > 2.7.4
> >
> 
> My preference for kvm-unit-tests is that we avoid tolerating
> unit tests that do things "wrong". This patch allows setup_vm
> to be called multiple times, but why do that? Why not just
> ensure it's only called once? If it looks like a mistake that's
> easy to make and hard to debug, then maybe we need an assert
> 
>  assert(!end_of_memory); /* ensure we haven't already called setup_vm */
> 
> or something.

Yeah, sure. The first two patches are just something good to have IMO,
I did it since I see we have similar thing in setup_idt(), and I feel
it good. I can replace it with an assertion.

Thanks.

-- peterx