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Date: Fri, 02 Apr 2010 17:43:35 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] provide opaque CPUState to files that are
	compiled once
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To: Anthony Liguori <anthony@codemonkey.ws>
Cc: qemu-devel@nongnu.org

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.

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.

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.

Paolo