From: Gleb Natapov <gleb@redhat.com>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
Avi Kivity <avi@redhat.com>,
kvm@vger.kernel.org, qemu-devel@nongnu.org
Subject: [Qemu-devel] Re: [PATCH v4 03/10] x86: Extend validity of cpu_is_bsp
Date: Sun, 7 Mar 2010 08:36:43 +0200 [thread overview]
Message-ID: <20100307063643.GN16909@redhat.com> (raw)
In-Reply-To: <20100304120354.GK16909@redhat.com>
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.
next prev parent reply other threads:[~2010-03-07 6:36 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-01 17:17 [Qemu-devel] [PATCH v4 00/10] qemu-kvm: Hook cleanups and yet more use of upstream code Jan Kiszka
2010-03-01 17:17 ` [Qemu-devel] [PATCH v4 01/10] qemu-kvm: Add KVM_CAP_X86_ROBUST_SINGLESTEP-awareness Jan Kiszka
2010-03-01 17:17 ` [Qemu-devel] [PATCH v4 02/10] qemu-kvm: Rework VCPU state writeback API Jan Kiszka
2010-03-01 17:17 ` [Qemu-devel] [PATCH v4 03/10] x86: Extend validity of cpu_is_bsp Jan Kiszka
2010-03-03 16:00 ` [Qemu-devel] " Gleb Natapov
2010-03-03 23:34 ` Jan Kiszka
2010-03-04 6:47 ` Gleb Natapov
2010-03-04 8:23 ` Jan Kiszka
2010-03-04 8:35 ` Gleb Natapov
2010-03-04 11:35 ` Jan Kiszka
2010-03-04 12:03 ` Gleb Natapov
2010-03-07 6:36 ` Gleb Natapov [this message]
2010-03-07 10:48 ` Jan Kiszka
2010-03-07 13:44 ` Jan Kiszka
2010-03-07 13:50 ` Gleb Natapov
2010-03-01 17:17 ` [Qemu-devel] [PATCH v4 04/10] qemu-kvm: Clean up mpstate synchronization Jan Kiszka
2010-03-01 17:17 ` [Qemu-devel] [PATCH v4 05/10] KVM: x86: Restrict writeback of VCPU state Jan Kiszka
2010-03-01 17:17 ` [Qemu-devel] [PATCH v4 06/10] qemu-kvm: Use VCPU event state for reset and vmsave/load Jan Kiszka
2010-03-01 17:17 ` [Qemu-devel] [PATCH v4 07/10] qemu-kvm: Cleanup/fix TSC and PV clock writeback Jan Kiszka
2010-03-01 17:17 ` [Qemu-devel] [PATCH v4 08/10] qemu-kvm: Clean up KVM's APIC hooks Jan Kiszka
2010-03-01 17:17 ` [Qemu-devel] [PATCH v4 09/10] qemu-kvm: Move kvm_set_boot_cpu_id Jan Kiszka
2010-03-01 17:17 ` [Qemu-devel] [PATCH v4 10/10] qemu-kvm: Bring qemu_init_vcpu back home Jan Kiszka
2010-03-01 17:21 ` [Qemu-devel] Re: [PATCH v4 00/10] qemu-kvm: Hook cleanups and yet more use of upstream code Jan Kiszka
2010-03-01 20:01 ` Marcelo Tosatti
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