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Re: [Qemu-devel] [0.14?][PATCH 3/4] ioapic: Prepare for base address rel
From: |
Jan Kiszka |
Subject: |
Re: [Qemu-devel] [0.14?][PATCH 3/4] ioapic: Prepare for base address relocation |
Date: |
Thu, 03 Feb 2011 19:01:17 +0100 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
On 2011-02-03 18:54, Blue Swirl wrote:
> On Thu, Feb 3, 2011 at 5:43 PM, Jan Kiszka <address@hidden> wrote:
>> On 2011-02-03 18:36, Blue Swirl wrote:
>>> On Thu, Feb 3, 2011 at 5:18 PM, Jan Kiszka <address@hidden> wrote:
>>>> On 2011-02-03 18:03, Blue Swirl wrote:
>>>>> On Thu, Feb 3, 2011 at 2:55 PM, Jan Kiszka <address@hidden> wrote:
>>>>>> The registers of real IOAPICs can be relocated during runtime (via
>>>>>> chipset registers). We don't support this yet, but qemu-kvm carries the
>>>>>> current base address in its version 2 vmstate.
>>>>>>
>>>>>> To align both implementations for migratability, add the proper
>>>>>> infrastructure to accept initial as well as updated base addresses and
>>>>>> include the current address in the vmstate. This is done in a way that
>>>>>> will also allow multiple IOAPICs in the future.
>>>>>
>>>>> Nack, the addresses should be device properties.
>>>>
>>>> Hmm.... we could make default_base_address a property. Will change that.
>>>> But current_base_address is just the same as apicbase and can't be a
>>>> property.
>>>
>>> Oh, right. What will current_base_address used for? Why can't board
>>> just unmap IOAPIC from current address and remap it at the new
>>> address? Then the device would not need to know its base address.
>>
>> The board could do this. The question is where we put this service, in
>> the context if the IOAPIC as ioapic_set_base_address (compare to
>> cpu_set_apic_base - which is buggy as it lacks sysbus_mmio_map) or into
>> each and every board code. In the latter case, the boards would also be
>> responsible for saving/restoring the address.
>
> How is the device relocated? Where are the chipset registers you mention?
Intel's PIIX chipsets contain a register called APICBASE (but it means
the IOAPIC), and that defines the location. The analogy in the APIC
world is the MSR_IA32_APICBASE which we maintain via the APIC state.
Jan
--
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux
- [Qemu-devel] [0.14?][PATCH 2/4] ioapic: Save/restore irr, (continued)
- [Qemu-devel] [0.14?][PATCH 2/4] ioapic: Save/restore irr, Jan Kiszka, 2011/02/03
- [Qemu-devel] [0.14?][PATCH 1/4] ioapic: Implement EOI handling for level-triggered IRQs, Jan Kiszka, 2011/02/03
- [Qemu-devel] [0.14?][PATCH 4/4] ioapic: Style & magics cleanup, Jan Kiszka, 2011/02/03
- [Qemu-devel] [0.14?][PATCH 3/4] ioapic: Prepare for base address relocation, Jan Kiszka, 2011/02/03
- Re: [Qemu-devel] [0.14?][PATCH 3/4] ioapic: Prepare for base address relocation, Blue Swirl, 2011/02/03
- Re: [Qemu-devel] [0.14?][PATCH 3/4] ioapic: Prepare for base address relocation, Jan Kiszka, 2011/02/03
- Re: [Qemu-devel] [0.14?][PATCH 3/4] ioapic: Prepare for base address relocation, Blue Swirl, 2011/02/03
- Re: [Qemu-devel] [0.14?][PATCH 3/4] ioapic: Prepare for base address relocation, Jan Kiszka, 2011/02/03
- Re: [Qemu-devel] [0.14?][PATCH 3/4] ioapic: Prepare for base address relocation, Blue Swirl, 2011/02/03
- Re: [Qemu-devel] [0.14?][PATCH 3/4] ioapic: Prepare for base address relocation,
Jan Kiszka <=
- Re: [Qemu-devel] [0.14?][PATCH 3/4] ioapic: Prepare for base address relocation, Blue Swirl, 2011/02/03
- Re: [Qemu-devel] [0.14?][PATCH 3/4] ioapic: Prepare for base address relocation, Jan Kiszka, 2011/02/03
- Re: [Qemu-devel] [0.14?][PATCH 3/4] ioapic: Prepare for base address relocation, Blue Swirl, 2011/02/03
- Re: [Qemu-devel] [0.14?][PATCH 3/4] ioapic: Prepare for base address relocation, Jan Kiszka, 2011/02/03
- Re: [Qemu-devel] [0.14?][PATCH 3/4] ioapic: Prepare for base address relocation, Blue Swirl, 2011/02/03
- Re: [Qemu-devel] [0.14?][PATCH 3/4] ioapic: Prepare for base address relocation, Jan Kiszka, 2011/02/03