Set DE_CFG[9] -- a chickenbit which stops Zenbleed. The chickenbit may
authorderaadt <deraadt@openbsd.org>
Mon, 24 Jul 2023 14:53:58 +0000 (14:53 +0000)
committerderaadt <deraadt@openbsd.org>
Mon, 24 Jul 2023 14:53:58 +0000 (14:53 +0000)
commitc2cf4345bb542c4405ab5e11724350bc1740044e
tree09340ccd54c3d35415a425d7c3c4c32dba37b654
parent860234e8477849e80921da12a4ca79bb3e7e7d88
Set DE_CFG[9] -- a chickenbit which stops Zenbleed.  The chickenbit may
have other side-effects (not disclosed by AMD), and firmwares fixes may
be better (and have other side-effects, same story).  Newer processors
will probably be validated more carefully by AMD.
Issue found by Tavis Ormandy.
This is errata 7.2/033_amdcpu.patch.sig and 7.3/011_amdcpu.patch.sig
Zenbleed also blocked on select cpus by using errata
7.3/012_amdfirmware.patch.sig + 7.3/013_amdcpufirmware.patch /
7.2/034_amdfirmware.patch.sig + 7.2/035_amdcpufirmware.patch.sig
which load AMD cpu firmwares (firmware.openbsd.org is updated often to
contain the best firmwares)
ok jsg
sys/arch/amd64/amd64/cpu.c
sys/arch/amd64/include/specialreg.h
sys/arch/i386/i386/machdep.c
sys/arch/i386/include/specialreg.h