linux-kernel - [PATCH] x86/mm/sme: Fix definition of PMD_FLAGS_DEC

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Message-Id: <20201109173543.551282-1-nivedita@alum.mit.edu>
Date:   Mon,  9 Nov 2020 12:35:43 -0500
From:   Arvind Sankar <nivedita@...m.mit.edu>
To:     Tom Lendacky <thomas.lendacky@....com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] x86/mm/sme: Fix definition of PMD_FLAGS_DEC_WP

The PAT bit is in different locations for 4k and 2M/1G page table
entries.

Add a definition for _PAGE_LARGE_CACHE_MASK to represent the three
caching bits (PWT, PCD, PAT), similar to _PAGE_CACHE_MASK for 4k pages,
and use it in the definition of PMD_FLAGS_DEC_WP to get the correct PAT
index for write-protected pages.

Remove a duplication definition of _PAGE_PAT_LARGE.

Signed-off-by: Arvind Sankar <nivedita@...m.mit.edu>
---
 arch/x86/include/asm/pgtable_types.h | 3 +--
 arch/x86/mm/mem_encrypt_identity.c   | 4 ++--
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index 816b31c68550..f24d7ef8fffa 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -155,6 +155,7 @@ enum page_cache_mode {
 #define _PAGE_ENC		(_AT(pteval_t, sme_me_mask))
 
 #define _PAGE_CACHE_MASK	(_PAGE_PWT | _PAGE_PCD | _PAGE_PAT)
+#define _PAGE_LARGE_CACHE_MASK	(_PAGE_PWT | _PAGE_PCD | _PAGE_PAT_LARGE)
 
 #define _PAGE_NOCACHE		(cachemode2protval(_PAGE_CACHE_MODE_UC))
 #define _PAGE_CACHE_WP		(cachemode2protval(_PAGE_CACHE_MODE_WP))
@@ -176,8 +177,6 @@ enum page_cache_mode {
 #define __pgprot(x)		((pgprot_t) { (x) } )
 #define __pg(x)			__pgprot(x)
 
-#define _PAGE_PAT_LARGE		(_AT(pteval_t, 1) << _PAGE_BIT_PAT_LARGE)
-
 #define PAGE_NONE	     __pg(   0|   0|   0|___A|   0|   0|   0|___G)
 #define PAGE_SHARED	     __pg(__PP|__RW|_USR|___A|__NX|   0|   0|   0)
 #define PAGE_SHARED_EXEC     __pg(__PP|__RW|_USR|___A|   0|   0|   0|   0)
diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c
index 733b983f3a89..6c5eb6f3f14f 100644
--- a/arch/x86/mm/mem_encrypt_identity.c
+++ b/arch/x86/mm/mem_encrypt_identity.c
@@ -45,8 +45,8 @@
 #define PMD_FLAGS_LARGE		(__PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL)
 
 #define PMD_FLAGS_DEC		PMD_FLAGS_LARGE
-#define PMD_FLAGS_DEC_WP	((PMD_FLAGS_DEC & ~_PAGE_CACHE_MASK) | \
-				 (_PAGE_PAT | _PAGE_PWT))
+#define PMD_FLAGS_DEC_WP	((PMD_FLAGS_DEC & ~_PAGE_LARGE_CACHE_MASK) | \
+				 (_PAGE_PAT_LARGE | _PAGE_PWT))
 
 #define PMD_FLAGS_ENC		(PMD_FLAGS_LARGE | _PAGE_ENC)
 
-- 
2.26.2