Linux Patch Coming To Fix Under-Reported AMD Zen 5 TLB Sizes

A minor reporting issue on Linux that has gone unaddressed until now is for properly conveying the Translation Lookaside Buffer (TLB) sizes on AMD Zen 5 processors. With Zen 5 CPUs, AMD began reporting the TLB sizes as multiples of 32. But the Linux kernel was never adapted to check the necessary bit and make the appropriate calculation. There is now a patch to correct that so the AMD EPYC and Ryzen Zen 5 TLB sizes will be reported correctly under the likes of /proc/cpuinfo. This also carries forward for Zen 6 and future AMD CPUs using this bit for reporting TLB sizes as multiples of 32. This patch fixes the AMD TLB size reporting. Currently it's in the x86/cpu branch. With it being in that branch rather than one of TIP's "urgent" branches, it will presumably be submitted for the Linux 7.4 merge window rather than the urgent route as a Linux 7.3 fix.