Re: [PATCH V8 07/44] x86/pkeys: Add PKS CPU feature bit

[Ira Weiny]

On Fri, Jan 28, 2022 at 03:05:36PM -0800, Dave Hansen wrote:
> On 1/27/22 09:54, ira.weiny@xxxxxxxxx wrote:
> > From: Ira Weiny <ira.weiny@xxxxxxxxx>
> > 
> > Protection Keys for Supervisor pages (PKS) enables fast, hardware thread
> > specific, manipulation of permission restrictions on supervisor page
> 
> Nit: should be "hardware-thread-specific".
> 
> > mappings.  It uses the same mechanism of Protection Keys as those on
> > User mappings but applies that mechanism to supervisor mappings using a
> > supervisor specific MSR.
> 
> "supervisor-specific"
> 
> 	Memory Protection Keys (pkeys) provides a mechanism for
> 	enforcing page-based protections, but without requiring
> 	modification of the page tables when an application changes
> 	protection domains.
> 
> 	The kernel currently supports the pkeys for userspace (PKU)
> 	architecture.  That architecture has been extended to
> 	additionally support supervisor mappings.  The supervisor
> 	support is referred to as PKS.
> 
> I probably wouldn't mention the MSR unless you want to say:
> 
> 	The main difference between PKU and PKS is that PKS does not
> 	introduce any new instructions to write to its register.  The
> 	register is exposed as a normal MSR and is accessed with the
> 	normal MSR instructions.
> 
> 
> > The CPU indicates support for PKS in bit 31 of the ECX register after a
> > cpuid instruction.
> 
> I'd just remove this sentence.  We don't need to rehash each tiny morsel
> of the architecture in a commit message.

All done.  Thanks for the verbiage.
Ira