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Date: Thu, 19 Aug 2010 14:33:13 -0500
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] [PATCH v2 0/7] APIC/IOAPIC cleanup
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To: Blue Swirl <blauwirbel@gmail.com>
Cc: "Liu >> \"Liu, Jinsong\"" <jinsong.liu@intel.com>, Avi Kivity <avi@redhat.com>, qemu-devel <qemu-devel@nongnu.org>, Paul Brook <paul@codesourcery.com>

On 06/12/2010 04:14 PM, Blue Swirl wrote:
> Clean up APIC and IOAPIC. Convert both devices to qdev.
>
> v1->v2:
> Remove apic.h reorganization.
> Add IOAPIC and APIC qdev conversions.
> Use CPUState also in 5/7. However on 6/7 we have to again use void *
> because of VMState limitations. VMState gurus, please comment.
>    

I'm late to the game here, but I'm not sure converting the APIC to qdev 
makes a lot of sense conceptually.

qdev models devices that exist on a bus, but the local APIC actually 
lives on the processor core.  It's extremely unique in that it actually 
maps a physical memory region different depending on the actual core.  
It really belongs as part of the CPU emulation and not as part of the 
device emulation.

For now, the practical problem is that you can't hotplug a CPU because 
that creates an APIC which lives on the Sysbus which does not allow 
hotplug.  Making sysbus allow hotplug is definitely note the right 
answer though.

I think the options are to allow non-bus devices (like the APIC) or make 
the APIC a special case that's part of the CPU emulation.

> Blue Swirl (7):
>    ioapic: unexport ioapic_set_irq
>    ioapic: convert to qdev
>    apic: avoid passing CPUState from devices
>    apic: avoid passing CPUState from CPU code
>    apic: avoid using CPUState internals
>    apic: convert to qdev
>    apic: qdev conversion cleanup
>
>   hw/apic.c               |  174 +++++++++++++++++++++++-----------------------
>   hw/apic.h               |   21 ++++--
>   hw/ioapic.c             |   47 ++++++++----
>   hw/pc.c                 |   74 ++++++++++++++++++--
>   hw/pc.h                 |    4 +-
>   hw/pc_piix.c            |   19 +++++-
>   qemu-common.h           |    2 +-
>   target-i386/cpu.h       |   28 +++++---
>   target-i386/cpuid.c     |    6 ++
>   target-i386/helper.c    |    4 +-
>   target-i386/kvm.c       |   14 ++--
>   target-i386/op_helper.c |    8 +-
>   12 files changed, 258 insertions(+), 143 deletions(-)
>
>