Re: [PATCH v3 1/2] x86, mwaitt: add monitorx and mwaitx instruction

[Huang Rui <ray.huang@amd.com>]

On Thu, Jun 11, 2015 at 04:19:04PM +0200, Borislav Petkov wrote:
> On Thu, Jun 11, 2015 at 10:14:10PM +0800, Huang Rui wrote:
> > On AMD Carrizo processors (Family 15h, Model 60h-6fh), there is a new
> > feature called MWAITT (Mwait with a timer) as an extension of
> > Monitor/Mwait.
> > 
> > MWAITT, another name is MWAITX (MWAIT with extensions), has a configurable
> > timer that causes MWAITX to exit on expiration.
> > 
> > Compared with MONITOR/MWAIT, there are minor differences in opcode and
> > input parameters.
> > 
> > MWAITX ECX[1]: enable timer if set
> > MWAITX EBX[31:0]: max wait time expressed in SW P0 clocks
> > 
> >                 MWAIT                           MWAITX
> > opcode          0f 01 c9           |            0f 01 fb
> > ECX[0]                  value of RFLAGS.IF seen by instruction
> > ECX[1]          unused/#GP if set  |            enable timer if set
> > ECX[31:2]                     unused/#GP if set
> > EAX                           unused (reserve for hint)
> > EBX[31:0]       unused             |            max wait time (loops)
> > 
> >                 MONITOR                         MONITORX
> > opcode          0f 01 c8           |            0f 01 fa
> > EAX                     (logical) address to monitor
> > ECX                     #GP if not zero
> > 
> > The software P0 frequency is the same as the TSC frequency.
> > 
> > Max timeout = EBX/(TSC frequency)
> 
> As suggested last time, please put the description of MWAITX over
> __mwaitx() in the code as comments below. See below.
> 

Apology to miss that. Will do it at once.

Thanks,
Rui