linux-kernel - [PATCH v8 03/16] x86/cpu/mtrr: Support TOP

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Date:   Sun, 23 Sep 2018 17:34:16 +0800
From:   Pu Wen <puwen@...on.cn>
To:     bp@...en8.de, tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
        x86@...nel.org, thomas.lendacky@....com
Cc:     linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
        Pu Wen <puwen@...on.cn>
Subject: [PATCH v8 03/16] x86/cpu/mtrr: Support TOP_MEM2 and get MTRR number

The Hygon Dhyana CPU has a special magic MSR way to force WB for
memory >4GB, and support TOP_MEM2. Therefore, it is necessary to
add Hygon Dhyana support in amd_special_default_mtrr().

The number of variable MTRRs for Hygon is 2 as AMD's.

Signed-off-by: Pu Wen <puwen@...on.cn>
Reviewed-by: Borislav Petkov <bp@...e.de>
---
 arch/x86/kernel/cpu/mtrr/cleanup.c | 3 ++-
 arch/x86/kernel/cpu/mtrr/mtrr.c    | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/mtrr/cleanup.c b/arch/x86/kernel/cpu/mtrr/cleanup.c
index 765afd5..3668c5d 100644
--- a/arch/x86/kernel/cpu/mtrr/cleanup.c
+++ b/arch/x86/kernel/cpu/mtrr/cleanup.c
@@ -831,7 +831,8 @@ int __init amd_special_default_mtrr(void)
 {
 	u32 l, h;
 
-	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
+	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
+	    boot_cpu_data.x86_vendor != X86_VENDOR_HYGON)
 		return 0;
 	if (boot_cpu_data.x86 < 0xf)
 		return 0;
diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.c b/arch/x86/kernel/cpu/mtrr/mtrr.c
index 9a19c80..507039c 100644
--- a/arch/x86/kernel/cpu/mtrr/mtrr.c
+++ b/arch/x86/kernel/cpu/mtrr/mtrr.c
@@ -127,7 +127,7 @@ static void __init set_num_var_ranges(void)
 
 	if (use_intel())
 		rdmsr(MSR_MTRRcap, config, dummy);
-	else if (is_cpu(AMD))
+	else if (is_cpu(AMD) || is_cpu(HYGON))
 		config = 2;
 	else if (is_cpu(CYRIX) || is_cpu(CENTAUR))
 		config = 8;
-- 
2.7.4