linux-kernel - [PATCH 12/12] x86/mm: only invalidate final translations with INVLPGB

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Message-ID: <20241230175550.4046587-13-riel@surriel.com>
Date: Mon, 30 Dec 2024 12:53:13 -0500
From: Rik van Riel <riel@...riel.com>
To: x86@...nel.org
Cc: linux-kernel@...r.kernel.org,
	kernel-team@...a.com,
	dave.hansen@...ux.intel.com,
	luto@...nel.org,
	peterz@...radead.org,
	tglx@...utronix.de,
	mingo@...hat.com,
	bp@...en8.de,
	hpa@...or.com,
	akpm@...ux-foundation.org,
	nadav.amit@...il.com,
	zhengqi.arch@...edance.com,
	linux-mm@...ck.org,
	Rik van Riel <riel@...riel.com>
Subject: [PATCH 12/12] x86/mm: only invalidate final translations with INVLPGB

Use the INVLPGB_FINAL_ONLY flag when invalidating mappings with INVPLGB.
This way only leaf mappings get removed from the TLB, leaving intermediate
translations cached.

On the (rare) occasions where we free page tables we do a full flush,
ensuring intermediate translations get flushed from the TLB.

Signed-off-by: Rik van Riel <riel@...riel.com>
---
 arch/x86/include/asm/invlpgb.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/invlpgb.h b/arch/x86/include/asm/invlpgb.h
index 862775897a54..2669ebfffe81 100644
--- a/arch/x86/include/asm/invlpgb.h
+++ b/arch/x86/include/asm/invlpgb.h
@@ -51,7 +51,7 @@ static inline void invlpgb_flush_user(unsigned long pcid,
 static inline void invlpgb_flush_user_nr(unsigned long pcid, unsigned long addr,
 					 int nr, bool pmd_stride)
 {
-	__invlpgb(0, pcid, addr, nr - 1, pmd_stride, INVLPGB_PCID | INVLPGB_VA);
+	__invlpgb(0, pcid, addr, nr - 1, pmd_stride, INVLPGB_PCID | INVLPGB_VA | INVLPGB_FINAL_ONLY);
 }
 
 /* Flush all mappings for a given ASID, not including globals. */
-- 
2.47.1