On 7/14/19 8:26 AM, Mick wrote: > Then I came across this old message regarding Piledriver CPUs: > https://lists.debian.org/debian-security/2016/03/msg00084.html The > post refers to model 2 of cpu family 21. Not all models in the same > family, only model 2. So I am thinking although patch files are named > per CPU family, whether they are applicable and applied as an update > to the CPU is probably determined by the particular CPU *model*. > Logically, errata in previous CPU revisions may have been fixed in > later models of the same family and therefore such microcode updates > would not be needed. When offered by the OS the CPU won't select to > have them applied. This explains why my AMD models, which are later > revisions of the same 15h family do not apply any microcode updates - > they don't need them. Please share if you know differently and thank > you all for your responses. Remember a while back when I mentioned that "lwp" had disappeared from my /proc/cpuinfo? They restored "lwp" with this commit : > https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/commit/?id=7518922bd5b98b137af7aaf3c836f5a498e91609 So it stands to reason that the microcode only applies specific patches to specific problems per CPU.
Reference : > Darkstar ~ # cat /proc/cpuinfo > processor : 0 > vendor_id : AuthenticAMD > cpu family : 21 > model : 2 > model name : AMD FX(tm)-9590 Eight-Core Processor > stepping : 0 > microcode : 0x6000852 > cpu MHz : 4685.390 > cache size : 2048 KB Output of /sys/devices/system/cpu/vulnerabilities : > > Darkstar ~ # cat /sys/devices/system/cpu/vulnerabilities/l1tf > Not affected > Darkstar ~ # cat /sys/devices/system/cpu/vulnerabilities/mds > Not affected > Darkstar ~ # cat /sys/devices/system/cpu/vulnerabilities/meltdown > Not affected > Darkstar ~ # cat > /sys/devices/system/cpu/vulnerabilities/spec_store_bypass > Mitigation: Speculative Store Bypass disabled > Darkstar ~ # cat /sys/devices/system/cpu/vulnerabilities/spectre_v1 > Mitigation: __user pointer sanitization > Darkstar ~ # cat /sys/devices/system/cpu/vulnerabilities/spectre_v2 > Mitigation: Full AMD retpoline, IBPB: always-on, STIBP: disabled, RSB > filling Corbin
