Re: [Qemu-devel] [PATCH 1/1] i386: Add PKU/OSPKE on Skylake-Server CPU model

[Tao Xu]

On 10/25/18 9:28 PM, Eduardo Habkost wrote:
> On Wed, Oct 17, 2018 at 12:48:58PM +0200, Paolo Bonzini wrote:
> > On 17/10/2018 11:30, Tao Xu wrote:
> > > As the release document ref below link (page 13):
> > > https://software.intel.com/sites/default/files/managed/c5/15/\
> > > architecture-instruction-set-extensions-programming-reference.pdf
> > >
> > > PKU is supported in Skylake Server (Only Server) and later, and
> > > on Intel(R) Xeon(R) Processor Scalable Family. OSPKE is to reads
> > > the value of PKRU (Instruction of PKU) into EAX and clears EDX.
> > > So PKU/OSPKE are supposed to be in Skylake-Server CPU model.
> > > And PKU/OSPKE 's CPUID has been exposed to QEMU. But PKU/OSPKE
> > > can't be find in Skylake-Server CPU model in the code.
> > > So this patch will fix PKU/OSPKE this issue in Skylake-Server
> > > CPU model.
> > OSPKE is not needed, since it is added automatically based on CR4 (and
> > is not set on boot).
> Correct.
>
> > Also, the guru of CPU model compatibility is Eduardo, so I'll wait for
> > him to chime in anyway.
> Sorry for taking so long to reply.  This can be safely done only
> if every host that is able to run Skylake-Server today is
> guaranteed to support PKU.  Is that the case?
>
> You'll also need Skylake-Server-*-cpu.pku=off entries on
> PC_COMPAT_3_0 to keep PKU disabled on pc-*-3.0 and older.
Thank you Eduardo,


But I can't find PC_COMPAT_3_0 in  include/hw/i386/pc.h. Will it exist on

QEMU 3.1 and will I add "pku=off" after QEMU 3.1  release?


Best Regard

Tao Xu