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[Qemu-devel] Re: [PATCH v4 03/10] x86: Extend validity of cpu_is_bsp
From: |
Gleb Natapov |
Subject: |
[Qemu-devel] Re: [PATCH v4 03/10] x86: Extend validity of cpu_is_bsp |
Date: |
Sun, 7 Mar 2010 08:36:43 +0200 |
On Thu, Mar 04, 2010 at 02:03:54PM +0200, Gleb Natapov wrote:
> > BTW, do real systems allow to hot plug BSP as well? Or how is the case
> > handled when you unplug the BSP and then reboot the box?
> >
> Did you mean hot unplug BSP? OS determines what CPU is BSP by checking
> BSP bit in APIC base register. My guess is that there is some pin on CPU
> which value is mirrored as BSP bit in APIC base register. Board may have
> some logic to check what sockets are populated and chose one of them as
> BSP by pulling its pin up. But this is only guess.
>
Actually this is much more simple:
SDM 8.4.1:
The MP initialization protocol defines two classes of processors: the
bootstrap processor (BSP) and the application processors (APs). Following
a power-up or RESET of an MP system, system hardware dynamically selects
one of the processors on the system bus as the BSP. The remaining
processors are designated as APs.
And by "hardware" they mean CPUs themselves over apic BUS.
--
Gleb.
- [Qemu-devel] [PATCH v4 07/10] qemu-kvm: Cleanup/fix TSC and PV clock writeback, (continued)
- [Qemu-devel] [PATCH v4 07/10] qemu-kvm: Cleanup/fix TSC and PV clock writeback, Jan Kiszka, 2010/03/01
- [Qemu-devel] [PATCH v4 10/10] qemu-kvm: Bring qemu_init_vcpu back home, Jan Kiszka, 2010/03/01
- [Qemu-devel] [PATCH v4 03/10] x86: Extend validity of cpu_is_bsp, Jan Kiszka, 2010/03/01
- [Qemu-devel] Re: [PATCH v4 03/10] x86: Extend validity of cpu_is_bsp, Gleb Natapov, 2010/03/03
- [Qemu-devel] Re: [PATCH v4 03/10] x86: Extend validity of cpu_is_bsp, Jan Kiszka, 2010/03/03
- [Qemu-devel] Re: [PATCH v4 03/10] x86: Extend validity of cpu_is_bsp, Gleb Natapov, 2010/03/04
- [Qemu-devel] Re: [PATCH v4 03/10] x86: Extend validity of cpu_is_bsp, Jan Kiszka, 2010/03/04
- [Qemu-devel] Re: [PATCH v4 03/10] x86: Extend validity of cpu_is_bsp, Gleb Natapov, 2010/03/04
- [Qemu-devel] Re: [PATCH v4 03/10] x86: Extend validity of cpu_is_bsp, Jan Kiszka, 2010/03/04
- [Qemu-devel] Re: [PATCH v4 03/10] x86: Extend validity of cpu_is_bsp, Gleb Natapov, 2010/03/04
- [Qemu-devel] Re: [PATCH v4 03/10] x86: Extend validity of cpu_is_bsp,
Gleb Natapov <=
- [Qemu-devel] Re: [PATCH v4 03/10] x86: Extend validity of cpu_is_bsp, Jan Kiszka, 2010/03/07
- [Qemu-devel] Re: [PATCH v4 03/10] x86: Extend validity of cpu_is_bsp, Jan Kiszka, 2010/03/07
- [Qemu-devel] Re: [PATCH v4 03/10] x86: Extend validity of cpu_is_bsp, Gleb Natapov, 2010/03/07
[Qemu-devel] Re: [PATCH v4 00/10] qemu-kvm: Hook cleanups and yet more use of upstream code, Jan Kiszka, 2010/03/01
[Qemu-devel] Re: [PATCH v4 00/10] qemu-kvm: Hook cleanups and yet more use of upstream code, Marcelo Tosatti, 2010/03/01