Re: [PATCH v2 0/3] KVM: x86: use pic/ioapic destructor when proper

["Radim Krčmář" <rkrcmar@redhat.com>]

2017-03-16 14:04+0800, Peter Xu:
> On Wed, Mar 15, 2017 at 12:15:24PM +0100, David Hildenbrand wrote:
>> Am 15.03.2017 um 09:59 schrieb Peter Xu:
>> > On Wed, Mar 15, 2017 at 09:47:14AM +0100, David Hildenbrand wrote:
>> >> Am 15.03.2017 um 09:01 schrieb Peter Xu:
>> >>> v2:
>> >>> - add one more patch (patch 2 in v2) to check pic/ioapic's
>> >>>   existance before destroying them
>> >>
>> >> Patch 2+3 without 1 should work, too, right?
>> > 
>> > We may need that? When destroy VM, it's:
>> > 
>> >   kvm_destroy_vm()
>> >     foreach (bus) do kvm_io_bus_destroy()
>> >       kfree(bus)                          <--- [1]
>> >     kvm_arch_destroy_vm()
>> >       kvm_pic_destroy()
>> >         kvm_io_bus_unregister_dev()       <--- [2]
>> > 
>> 
>> Wouldn't the natural way be
>> 
>> 1. kvm_arch_destroy_vm()
>> 2. foreach (bus) do kvm_io_bus_destroy()
>> 	kfree(bus)
>> 
>> Then we wouldn't have to deal with suddenly removed buses. But maybe
>> that order is of importance here ...
> 
> I'll leave this question for Paolo/Radim, or anyone knows this better
> than me. :-)

I'd like if kvm_destroy_vm() looked like kvm_create_vm() in reverse and
the current order is closer to that.

I don't think there is dependency between those two and we can easily
reverse them in kvm_create_vm(), so go ahead if you get better code out
of it in kvm_arch_destroy_vm(). :)