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Re: [Qemu-devel] [PATCH v4 0/3] bugs fix for hpet
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH v4 0/3] bugs fix for hpet |
Date: |
Wed, 04 Sep 2013 09:03:30 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130805 Thunderbird/17.0.8 |
Il 04/09/2013 07:29, liu ping fan ha scritto:
> On Tue, Sep 3, 2013 at 7:17 PM, Paolo Bonzini <address@hidden> wrote:
>> Il 02/09/2013 09:06, Liu Ping Fan ha scritto:
>>> note: I rebase it onto Stefan's net-next tree, since pc-1.7 has already
>>> been defined there.
>>>
>>> v4:
>>> use standard compat property to set hpet's interrupt compatibility
>>>
>>> v3:
>>> change hpet interrupt capablity on board's demand
>>>
>>>
>>> Liu Ping Fan (3):
>>> hpet: inverse polarity when pin above ISA_NUM_IRQS
>>> hpet: entitle more irq pins for hpet
>>> pc-1.6: add compatibility for hpet intcap on pc-*-1.6
>>>
>>> hw/timer/hpet.c | 27 +++++++++++++++++++++++----
>>> include/hw/i386/pc.h | 5 +++++
>>> 2 files changed, 28 insertions(+), 4 deletions(-)
>>>
>>
>> Looks good. But I have one question; should this be changed for PIIX
>> too, or should the 1.7 PIIX machine keep the old behavior? (I have no
>> idea).
>>
> Your suspicion is right. When going through PIIX4 spec, I found that
> the chipset was without ioapic integrated. So there is divergence for
> the compatibility of pc-piix-* and pc-q35-*. Can I code the hpet's
> compatiblity in pc-piix-1.7 to resolve this?
You could do something like what people suggested earlier in the review.
Change sysbus_try_create_simple to
qdev_try_create/sysbus_mmio_map/qdev_init in pc_basic_device_init (this
is one patch, going before v4 3/3). Then add a new argument to
pc_basic_device_init, and set the intcap property if the new argument is
nonzero (another patch, going before v4 3/3; where the new argument is
always 0). Finally, piix can pass 4 for the new argument, while q35 can
keep passing 0 (squashed in v4 3/3).
In other words, PIIX hardcodes the value 4, while Q35 uses compat
properties.
I still have a doubt. Can the PIIX HPET use interrupt 8? If so, this
won't work and we have to go back to the drawing board. But if it can
use interrupt 2 only, it will be okay.
Paolo
- [Qemu-devel] [PATCH v4 0/3] bugs fix for hpet, Liu Ping Fan, 2013/09/02
- [Qemu-devel] [PATCH v4 1/3] hpet: inverse polarity when pin above ISA_NUM_IRQS, Liu Ping Fan, 2013/09/02
- [Qemu-devel] [PATCH v4 2/3] hpet: entitle more irq pins for hpet, Liu Ping Fan, 2013/09/02
- [Qemu-devel] [PATCH v4 3/3] pc-1.6: add compatibility for hpet intcap on pc-*-1.6, Liu Ping Fan, 2013/09/02
- Re: [Qemu-devel] [PATCH v4 0/3] bugs fix for hpet, Stefan Hajnoczi, 2013/09/02
- Re: [Qemu-devel] [PATCH v4 0/3] bugs fix for hpet, Paolo Bonzini, 2013/09/03