INVLPGB feature support for Anolis 6.6 kernel · Pull Request !6204 · anolis/cloud-kernel

bugzilla: https://bugzilla.openanolis.cn/show_bug.cgi?id=28080

**INVLPGB feature support patches for OpenAnolis 23.1 (6.6 kernel)**

x86/mm: Consolidate full flush threshold decision
x86/mm: Add INVLPGB feature and Kconfig entry
x86/mm: Add INVLPGB support code
x86/mm: Use INVLPGB for kernel TLB flushes
x86/mm: Use broadcast TLB flushing in page reclaim
x86/mm: Add global ASID allocation helper functions
x86/mm: Handle global ASID context switch and TLB flush
x86/mm: Add global ASID process exit helpers
x86/mm: Enable broadcast TLB invalidation for multi-threaded processes
x86/mm: Enable AMD translation cache extensions
x86/mm: Always set the ASID valid bit for the INVLPGB instruction
x86/mm: Only do broadcast flush from reclaim if pages were unmapped
x86/mm: Disable INVLPGB when PTI is enabled
x86/mm: Fix early boot use of INVPLGB
x86/CPU/AMD: Disable INVLPGB on Zen2
anolis: configs: classify CONFIG_BROADCAST_TLB_FLUSH as L1 for x86 AMD64

This patch series includes 16 commits. The first  15 commits enhance x86 TLB invalidation on AMD CPUs by introducing INVLPGB support, fixing early boot and PTI interactions, adding global ASID management, and improving reclaim and kernel flush performance. The final commit designates CONFIG_BROADCAST_TLB_FLUSH as L1 for x86 AMD64 in Anolis configurations for build purposes.

**Key Bug Fixes**
 - Disabled INVLPGB on Zen2 (Cyan Skillfish) due to misconfigured CPUID causing oopses/panics.
 - Fixed early boot hang by initializing invlpgb_count_max to 1 before hardware enumeration.
 - Disabled INVLPGB when PTI is enabled to avoid bitmap overruns with large ASID counts.

**Feature Additions**
 - INVLPGB feature & Kconfig entry: Added kernel support code and CPUID enumeration for broadcast TLB invalidation.
 - Global ASID allocation helpers: Introduced functions to manage global ASIDs for multithreaded processes.
 - Global ASID context switch & exit: Added helpers to handle process exit and context switch with global ASIDs.
 - AMD Translation Cache Extensions (TCE): Enabled selective invalidation of intermediate mappings to reduce TLB misses.

**Logic & Performance Improvements**
 - Broadcast TLB invalidation for multi‑threaded processes: Assign broadcast ASIDs only to processes active on ≥4 CPUs, boosting scalability.
 - Kernel TLB flushes via INVLPGB: Removed IPIs for kernel address flushes, reducing overhead.
 - Page reclaim optimizations: Used broadcast flushes only when pages were unmapped, avoiding unnecessary invalidations.
 - Consolidated flush threshold decision: Reduced code duplication by centralizing full flush vs. partial invalidation logic.

**Robustness & Safety**
 - Always set ASID valid bit when executing INVLPGB to prevent host/guest cross‑TLB flushes.
 - Added stubs and guards for non‑broadcast configurations to satisfy compiler checks.

**Unit test**
---
```
1. Before Backport:

$ uname -r
  6.6.102_Base_INVPGb+
 $ lscpu | grep -wo invlpgb
 
 $ grep -i BROADCAST_TLB_FLUSH /boot/config-6.6.102_Base_INVPGb+
 
2. After Backport
 $ uname -r
  6.6.102_INVLPGb+
 $ lscpu | grep -wo invlpgb
  invlpgb
 $ grep -i BROADCAST_TLB_FLUSH /boot/config-6.6.102_INVLPGb+
  CONFIG_BROADCAST_TLB_FLUSH=y
```

类型	指派人员	状态
审查	xunlei 半叶枫尘 Artie Ding 冯光辉 Guixin Liu kun-llfl Xuchun Shang	已完成 (0/0人)
测试	小龙已测试通过	已完成 (1/1人)

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