This week’s batch of “x86/urgent” patches that were merged overnight for Linux 7.0 contain some fixes and other adjustments worth highlighting for both AMD and Intel.
The x86/urgent patches that are now in Git ahead of today’s Linux 7.0-rc3 release include a few notable items:
– IBPB-On-Entry for AMD SEV-SNP guest VMs was merged for making use of that new capability on AMD EPYC Zen 5 server processors. Just a few lines of code were needed for getting IBPB-on-Entry working for SEV-SNP VMs to provide greater security via forcing an Indirect Branch Predictor Barrier (IBPB) on entering the guest virtual machine to better prevent against possible speculative execution attacks.
– Separately, there is also a fix for possible AMD SEV guest boot failures in certain circumstances.
– Over on the Intel side there is a fix for Sub-NUMA Clustering topology enumeration bugs and different issues there. SNC enumeration became more complicated with Granite Rapids X and Clearwater Forest X processors that ended up exposing some kernel bugs and causing issue. So coming in as fixes for Linux 7.0 is cleaning up some of that SNC code. For more details on SNC, see Revisiting The SNC3 vs. HEX Mode Performance With Intel Xeon 6 Granite Rapids.
– A few other general x86 fixes were also merged as part of the x86/urgent pull.
The full list of patches can be found via this Git merge that is now in place ahead of Linux 7.0-rc3 due out later today.
