linux/debian/patches/patchset-zen/invlpgb-v9/0007-x86-mm-use-INVLPGB-in-flush_tlb_all.patch

From 1ef7edb5b2375d4010ed2ad0c7d87fcfa7ab4519 Mon Sep 17 00:00:00 2001
From: Rik van Riel <riel@surriel.com>
Date: Wed, 5 Feb 2025 23:43:26 -0500
Subject: x86/mm: use INVLPGB in flush_tlb_all

The flush_tlb_all() function is not used a whole lot, but we might
as well use broadcast TLB flushing there, too.

Signed-off-by: Rik van Riel <riel@surriel.com>
Tested-by: Manali Shukla <Manali.Shukla@amd.com>
---
 arch/x86/mm/tlb.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -1045,6 +1045,19 @@ void flush_tlb_mm_range(struct mm_struct
 }
 
 
+static bool broadcast_flush_tlb_all(void)
+{
+	if (!IS_ENABLED(CONFIG_X86_BROADCAST_TLB_FLUSH))
+		return false;
+
+	if (!cpu_feature_enabled(X86_FEATURE_INVLPGB))
+		return false;
+
+	guard(preempt)();
+	invlpgb_flush_all();
+	return true;
+}
+
 static void do_flush_tlb_all(void *info)
 {
 	count_vm_tlb_event(NR_TLB_REMOTE_FLUSH_RECEIVED);
@@ -1053,6 +1066,8 @@ static void do_flush_tlb_all(void *info)
 
 void flush_tlb_all(void)
 {
+	if (broadcast_flush_tlb_all())
+		return;
 	count_vm_tlb_event(NR_TLB_REMOTE_FLUSH);
 	on_each_cpu(do_flush_tlb_all, NULL, 1);
 }