From: "H. Peter Anvin" <hpa@zytor.com>
To: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
Suresh Siddha <suresh.b.siddha@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Ralf Jung <ralfjung-e@gmx.de>,
Yinghai Lu <yinghai@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] x86, ioapic: Reserve only 128 bytes for IOAPICs
Date: Fri, 26 Aug 2011 11:21:53 -0700 [thread overview]
Message-ID: <4E57E441.6030800@zytor.com> (raw)
In-Reply-To: <20110826180930.GA1930@sun>
On 08/26/2011 11:09 AM, Cyrill Gorcunov wrote:
>
> Yes, one of the spec is Intel's MP specification (as far as I remember).
> Letme re-check...
>
> | 3.6.5 APIC Memory Mapping
> |
> | "Unlike the local APICs, the I/O APICs are mapped to give shared access from all
> | processors, providing full symmetric I/O access. The default base address for the
> | first I/O APIC is 0FEC0_0000h. Subsequent I/O APIC addresses are assigned in
> | 4K increments. For example, the second I/O APIC is at 0FEC0_1000h. Non-default
> | APIC base addresses can be used if the MP configuration table is provided.
> | (Refer to Chapter 4.) However, the local APIC base address must be aligned
> | on a 4K boundary, and the I/O APIC base address must be aligned on a 1K
> | boundary."
>
> Ie -- 4K increment with 1K base address. If I find other sources I have in mind
> I'll ping you.
>
OK, so that explicitly specifies a 1K alignment. The 4K bit seems to be
a default policy and not a requirement.
-hpa
next prev parent reply other threads:[~2011-08-26 18:22 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-25 23:05 [PATCH 1/2] x86, ioapic: Reserve only 128 bytes for IOAPICs Bjorn Helgaas
2011-08-25 23:05 ` [PATCH 2/2] x86, ioapic: Announce resources reserved " Bjorn Helgaas
2011-08-25 23:33 ` [PATCH 1/2] x86, ioapic: Reserve only 128 bytes " Suresh Siddha
2011-08-26 0:17 ` Bjorn Helgaas
2011-08-26 1:41 ` H. Peter Anvin
2011-08-26 6:18 ` Yinghai Lu
2011-08-26 6:48 ` Cyrill Gorcunov
2011-08-26 9:22 ` Ralf Jung
2011-08-26 9:39 ` Cyrill Gorcunov
2011-08-26 9:53 ` Ralf Jung
2011-08-26 9:56 ` Cyrill Gorcunov
2011-08-26 6:22 ` Cyrill Gorcunov
2011-08-26 16:21 ` Bjorn Helgaas
2011-08-26 16:24 ` H. Peter Anvin
2011-08-26 18:09 ` Cyrill Gorcunov
2011-08-26 18:21 ` H. Peter Anvin [this message]
2011-08-26 19:15 ` Cyrill Gorcunov
[not found] ` <CAErSpo5kEw=VTVv-=_D3hQg5oRNL9yEyJUnpP0biH=t3WRXMZw@mail.gmail.com>
2011-08-26 21:09 ` Fwd: " Ralf Jung
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