On 11/12/21 16:50, Ira Weiny wrote:

On Tue, Aug 03, 2021 at 09:32:21PM -0700, 'Ira Weiny' wrote:

quoted

From: Ira Weiny <redacted>

The PKRS MSR is not managed by XSAVE.  It is preserved through a context
switch but this support leaves exception handling code open to memory
accesses during exceptions.

2 possible places for preserving this state were considered,
irqentry_state_t or pt_regs.[1]  pt_regs was much more complicated and
was potentially fraught with unintended consequences.[2]  However, Andy
came up with a way to hide additional values on the stack which could be
accessed as "extended_pt_regs".[3]

Andy,

I'm preparing to send V8 of this PKS work.  But I have not seen any feed back
since I originally implemented this in V4[1].

Does this meets your expectations?  Are there any issues you can see with this
code?

I think I'm generally okay with the approach to allocating space.  All 
of Thomas' comments still apply, though.  (Sorry, I'm horribly behind.)