Re: [Qemu-devel] [PATCH] provide opaque CPUState to files that are compiled once

[Blue Swirl <blauwirbel@gmail.com>]

On 4/2/10, Paolo Bonzini <pbonzini@redhat.com> wrote:
> On 04/02/2010 05:22 PM, Anthony Liguori wrote:
>
>
> > hw/* should never access CPUState.
> >
> > Can you give examples of when qemu-kvm needs this?
> >
>
>  Indirectly via header files.  The problem is that GCC poisoning complains
> on prototypes too.
>
>  qemu-kvm.h references CPUState and includes cpu.h, so with the latest
> changes all files that include qemu-kvm.h break, even if they don't require
> qemu-kvm.h.  With this patch they instead get the opaque definition via
> hw/hw.h (which includes cpu-common.h), and qemu-kvm.h can avoid including
> cpu.h.

This is why I added #ifndef NEED_CPU_H to kvm.h.

>  Another example is the new apic.h file created by Blue Swirl.  It
> references CPUState.  It includes apic_get_irq_delivered, so I placed
> apic_set_irq_delivered there too.  But apic_set_irq_delivered is used by
> i8259.c which is compiled once.

But i8259.c is compiled per target, grep Makefile.target?

>  There are other similar cases.  Without something like this patch as a
> stopgap measure, you have to make everything compile again per-target which
> is a huge mess of conflicts.

This is wrong. There are lot of other ways to handle the need without
resorting to per-target build.