SLAM: Spectre based on Linear Address Masking

[Alan Coopersmith <alan.coopersmith () oracle com>]

A vulnerability in closed source CPUs which open source OSes may need
to mitigate was disclosed today:

https://www.vusec.net/projects/slam/
https://github.com/vusec/slam
https://www.youtube.com/watch?v=y4wZ-tREaNk
https://x.com/vu5ec/status/1732099516621521003

The first page lists these processors as affected:

   - Existing AMD CPUs vulnerable to CVE-2020-12965;
   - Future Intel CPUs supporting LAM (both 4- and 5-level paging);
   - Future AMD CPUs supporting UAI and 5-level paging;
   - Future Arm CPUs supporting TBI and 5-level paging.

as it takes advantage of CPU features which allow masking off some bits of
pointer addresses to store additional data in, such as Intel’s Linear Address
Masking (LAM), AMD’s Upper Address Ignore (UAI), or ARM's Top-byte Ignore (TBI).

--
        -Alan Coopersmith-                 alan.coopersmith () oracle com
         Oracle Solaris Engineering - https://blogs.oracle.com/solaris