Re: [Qemu-devel] [PATCH for-1.4 11/12] target-i386: Topology & APIC ID utility functions

[Eduardo Habkost]

On Mon, Jan 21, 2013 at 05:22:44PM +0100, Andreas Färber wrote:
> Am 21.01.2013 17:10, schrieb Eduardo Habkost:
> > On Mon, Jan 21, 2013 at 12:28:21PM +0100, Andreas Färber wrote:
> >> Am 17.01.2013 21:59, schrieb Eduardo Habkost:
> >>> diff --git a/target-i386/topology.h b/target-i386/topology.h
> >>> new file mode 100644
> >>> index 0000000..833ab47
> >>> --- /dev/null
> >>> +++ b/target-i386/topology.h
> >>> @@ -0,0 +1,133 @@
> >>> +/*
> >>> + *  x86 CPU topology data structures and functions
> >>> + *
> >>> + *  Copyright (c) 2012 Red Hat Inc.
> >>> + *
> >>> + * Permission is hereby granted, free of charge, to any person obtaining 
> >>> a copy
> >>> + * of this software and associated documentation files (the "Software"), 
> >>> to deal
> >>> + * in the Software without restriction, including without limitation the 
> >>> rights
> >>> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or 
> >>> sell
> >>> + * copies of the Software, and to permit persons to whom the Software is
> >>> + * furnished to do so, subject to the following conditions:
> >>> + *
> >>> + * The above copyright notice and this permission notice shall be 
> >>> included in
> >>> + * all copies or substantial portions of the Software.
> >>> + *
> >>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
> >>> EXPRESS OR
> >>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 
> >>> MERCHANTABILITY,
> >>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT 
> >>> SHALL
> >>> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR 
> >>> OTHER
> >>> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 
> >>> ARISING FROM,
> >>> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
> >>> DEALINGS IN
> >>> + * THE SOFTWARE.
> >>> + */
> >>> +#ifndef TARGET_I386_TOPOLOGY_H
> >>> +#define TARGET_I386_TOPOLOGY_H
> >>> +
> >>> +/* This file implements the APIC-ID-based CPU topology enumeration logic,
> >>> + * documented at the following document:
> >>> + *   Intel® 64 Architecture Processor Topology Enumeration
> >>> + *   
> >>> http://software.intel.com/en-us/articles/intel-64-architecture-processor-topology-enumeration/
> >>> + *
> >>> + * This code should be compatible with AMD's "Extended Method" described 
> >>> at:
> >>> + *   AMD CPUID Specification (Publication #25481)
> >>> + *   Section 3: Multiple Core Calcuation
> >>> + * as long as:
> >>> + *  nr_threads is set to 1;
> >>> + *  OFFSET_IDX is assumed to be 0;
> >>> + *  CPUID Fn8000_0008_ECX[ApicIdCoreIdSize[3:0]] is set to 
> >>> apicid_core_width().
> >>> + */
> >>> +
> >>> +#include <stdint.h>
> >>> +#include <string.h>
> >>> +
> >>> +#include "qemu/bitops.h"
> >>> +
> >>> +/* APIC IDs can be 32-bit, but beware: APIC IDs > 255 require x2APIC 
> >>> support
> >>> + */
> >>> +typedef uint32_t apic_id_t;
> >>
> >> Is this file imported from somewhere?
> > 
> > It's used by PATCH 12/12, when actually implementing the topology-aware
> > APIC ID calculation in the CPU code.
> 
> I meant, is this file/code from Linux or some other project? :) Or did
> you write it from scratch? The commit message is a bit brief.

It was written from scratch.

> 
> I was thinking about whether an x86_... function prefix would be needed,
> but since these are static inline I think not.

Even being inline static, they could conflict with functions from other
headers if they are not unique. I plan to make them use a x86_ prefix in
the next version.

-- 
Eduardo