linux-kernel - [tip: x86/cpu] x86/mtrr: Split MTRR-specific handling from cache dis/enabling

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Message-ID: <166808291702.4906.9360364596007729426.tip-bot2@tip-bot2>
Date:   Thu, 10 Nov 2022 12:21:57 -0000
From:   "tip-bot2 for Juergen Gross" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Juergen Gross <jgross@...e.com>, Borislav Petkov <bp@...e.de>,
        x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: x86/cpu] x86/mtrr: Split MTRR-specific handling from cache dis/enabling

The following commit has been merged into the x86/cpu branch of tip:

Commit-ID:     4ad7149e46d048d3a543c96d35c1d255208dd33a
Gitweb:        https://git.kernel.org/tip/4ad7149e46d048d3a543c96d35c1d255208dd33a
Author:        Juergen Gross <jgross@...e.com>
AuthorDate:    Wed, 02 Nov 2022 08:47:02 +01:00
Committer:     Borislav Petkov <bp@...e.de>
CommitterDate: Thu, 10 Nov 2022 13:12:44 +01:00

x86/mtrr: Split MTRR-specific handling from cache dis/enabling

Split the MTRR-specific actions from cache_disable() and cache_enable()
into new functions mtrr_disable() and mtrr_enable().

Signed-off-by: Juergen Gross <jgross@...e.com>
Signed-off-by: Borislav Petkov <bp@...e.de>
Link: https://lore.kernel.org/r/20221102074713.21493-6-jgross@suse.com
Signed-off-by: Borislav Petkov <bp@...e.de>
---
 arch/x86/include/asm/mtrr.h        |  4 ++++
 arch/x86/kernel/cpu/mtrr/generic.c | 26 +++++++++++++++++++-------
 2 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/mtrr.h b/arch/x86/include/asm/mtrr.h
index 76d7260..12a16ca 100644
--- a/arch/x86/include/asm/mtrr.h
+++ b/arch/x86/include/asm/mtrr.h
@@ -48,6 +48,8 @@ extern void mtrr_aps_init(void);
 extern void mtrr_bp_restore(void);
 extern int mtrr_trim_uncached_memory(unsigned long end_pfn);
 extern int amd_special_default_mtrr(void);
+void mtrr_disable(void);
+void mtrr_enable(void);
 #  else
 static inline u8 mtrr_type_lookup(u64 addr, u64 end, u8 *uniform)
 {
@@ -87,6 +89,8 @@ static inline void mtrr_centaur_report_mcr(int mcr, u32 lo, u32 hi)
 #define set_mtrr_aps_delayed_init() do {} while (0)
 #define mtrr_aps_init() do {} while (0)
 #define mtrr_bp_restore() do {} while (0)
+#define mtrr_disable() do {} while (0)
+#define mtrr_enable() do {} while (0)
 #  endif
 
 #ifdef CONFIG_COMPAT
diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index 2f3fc28..0db0770 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -716,6 +716,21 @@ static unsigned long set_mtrr_state(void)
 	return change_mask;
 }
 
+void mtrr_disable(void)
+{
+	/* Save MTRR state */
+	rdmsr(MSR_MTRRdefType, deftype_lo, deftype_hi);
+
+	/* Disable MTRRs, and set the default type to uncached */
+	mtrr_wrmsr(MSR_MTRRdefType, deftype_lo & ~0xcff, deftype_hi);
+}
+
+void mtrr_enable(void)
+{
+	/* Intel (P6) standard MTRRs */
+	mtrr_wrmsr(MSR_MTRRdefType, deftype_lo, deftype_hi);
+}
+
 /*
  * Disable and enable caches. Needed for changing MTRRs and the PAT MSR.
  *
@@ -764,11 +779,8 @@ void cache_disable(void) __acquires(cache_disable_lock)
 	count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
 	flush_tlb_local();
 
-	/* Save MTRR state */
-	rdmsr(MSR_MTRRdefType, deftype_lo, deftype_hi);
-
-	/* Disable MTRRs, and set the default type to uncached */
-	mtrr_wrmsr(MSR_MTRRdefType, deftype_lo & ~0xcff, deftype_hi);
+	if (cpu_feature_enabled(X86_FEATURE_MTRR))
+		mtrr_disable();
 
 	/* Again, only flush caches if we have to. */
 	if (!static_cpu_has(X86_FEATURE_SELFSNOOP))
@@ -781,8 +793,8 @@ void cache_enable(void) __releases(cache_disable_lock)
 	count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
 	flush_tlb_local();
 
-	/* Intel (P6) standard MTRRs */
-	mtrr_wrmsr(MSR_MTRRdefType, deftype_lo, deftype_hi);
+	if (cpu_feature_enabled(X86_FEATURE_MTRR))
+		mtrr_enable();
 
 	/* Enable caches */
 	write_cr0(read_cr0() & ~X86_CR0_CD);