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Re: [Xen-devel] [PATCH] fix xenctl_cpumap translation to handle bitops accessed like arrays

  • To: Jimi Xenidis <jimix@xxxxxxxxxxxxxx>, Keir Fraser <keir@xxxxxxxxxxxxx>
  • From: Keir Fraser <keir@xxxxxxxxxxxxx>
  • Date: Mon, 18 Dec 2006 17:55:59 +0000
  • Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
  • Delivery-date: Mon, 18 Dec 2006 09:56:12 -0800
  • List-id: Xen developer discussion <xen-devel.lists.xensource.com>
  • Thread-index: AccizcYRBJKaBY7BEduEawAX8io7RQ==
  • Thread-topic: [Xen-devel] [PATCH] fix xenctl_cpumap translation to handle bitops accessed like arrays

On 18/12/06 16:50, "Jimi Xenidis" <jimix@xxxxxxxxxxxxxx> wrote:

>> another
>> a uint64_t. Perhaps we should fix so they pass down 8-bit units (as
>> the type
>> of xenctl_cpumap_t would suggest) and then we could have
>> byte_to_long_bitmap
>> and long_to_byte_bitmap in Xen
> Are you suggesting to still use bits in the bytes?
> If so, then do you want "C" ordering in the byte or arch bit ordering?
> Perhaps we simply to us the byte array as a list of CPU numbers, with
> -1 to terminate?

I mean bits 8k to 8k+7 inclusive are contained in byte at offset k in the
cpumap, and in the obvious order (8k is least significant bit; 8k+7 is most
significant). This is the byte-oriented bitmap type that your bitops.h goes
on about. Since xenctl_cpumap_t is defined as a byte array and byte count,
this interpretation would make sense.

 -- Keir

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