[PATCH] x86, pkeys: update documentation about availability

[Dave Hansen <dave.hansen@linux.intel.com>]

From: Dave Hansen <dave.hansen@linux.intel.com>

Now that CPUs that implement Memory Protection Keys are publicly
available we can be a bit less oblique about where it is available.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
---

 b/Documentation/x86/protection-keys.txt |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff -puN Documentation/x86/protection-keys.txt~pkeys-update Documentation/x86/protection-keys.txt
--- a/Documentation/x86/protection-keys.txt~pkeys-update	2017-11-09 10:36:53.381467202 -0800
+++ b/Documentation/x86/protection-keys.txt	2017-11-09 10:43:15.527466249 -0800
@@ -1,5 +1,10 @@
-Memory Protection Keys for Userspace (PKU aka PKEYs) is a CPU feature
-which will be found on future Intel CPUs.
+Memory Protection Keys for Userspace (PKU aka PKEYs) is a feature
+which is found on Intel's Skylake "Scalable Processor" Server CPUs.
+It will be avalable in future non-server parts.
+
+For anyone wishing to test or use this feature, it is available in
+Amazon's EC2 C5 instances and is known to work there using an Ubuntu
+17.04 image.
 
 Memory Protection Keys provides a mechanism for enforcing page-based
 protections, but without requiring modification of the page tables
_