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

[Eduardo Habkost]

On Fri, Oct 26, 2018 at 01:53:10PM +0800, Tao Xu wrote:
> 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?

PC_COMPAT_3_0 was added to qemu.git master a few weeks ago, by
commit 9b4cf107b09d18ac30f46fd1c4de8585ccba030c.

-- 
Eduardo