[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] [PATCH 4/4] xen/arm: arm64: Remove MPIDR multiprocessing extensions check

Hello Peng,

On 25/05/16 13:37, Peng Fan wrote:
On Wed, May 25, 2016 at 10:10:11AM +0800, Wei Chen wrote:
In ARM64, the MPIDR multiprocessing extensions bit is reserved to 1.
So, the value check for this bit is no longer necessary on ARM64.

 From ARM DDI0487A.G, I found the U bit for MPIDR_EL1:
Indicates a Uniprocessor system, as distinct from PE 0 in a multiprocessor 
system. The possible
values of this bit are:
0 Processor is part of a multiprocessor system.
1 Processor is part of a uniprocessor system.

It's not reserved to 1. Which doc are you refering to?

Please read carefully the patch. The check on MPDIR_EL1.U is kept, only the check to the RES1 bit ('M' for Aarch32) is removed.


Julien Grall

Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.