Description: Post-Barrier Return Stack Buffer Predictions (PBRSB)
References:
 https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00706.html
Notes:
Bugs:
upstream: pending [2b1299322016731d56807aa49254a5ea3080b6b3, ba6e31af2be96c4d0536f2152ed6f7b6c11bca47]
5.10-upstream-stable: needed
4.19-upstream-stable: needed
sid: pending (5.18.16-1) [bugfix/x86/pbrsb/0001-x86-speculation-Add-RSB-VM-Exit-protections.patch, bugfix/x86/pbrsb/0002-x86-speculation-Add-LFENCE-to-RSB-fill-sequence.patch]
5.10-bullseye-security: needed
4.19-buster-security: needed