linux-kernel - [PATCH v2 2/2] x86/cpu/intel: Clean-up TME code

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Message-ID: <87h6nhu7k6.fsf@jcompost-mobl.amr.corp.intel.com>
Date:   Mon, 25 Sep 2023 17:00:57 -0700
From:   "Compostella, Jeremy" <jeremy.compostella@...el.com>
To:     <linux-kernel@...r.kernel.org>, <x86@...nel.org>
Subject: [PATCH v2 2/2] x86/cpu/intel: Clean-up TME code

This patch improves the intel TME code quality by:
1. Moving the TME MSR definition to msr-index.h
2. Making the `mktme_status' variable an enum local to the
   detect_tme() function as this is the only function using it.

Signed-off-by: Jeremy Compostella <jeremy.compostella@...el.com>
---
 arch/x86/include/asm/msr-index.h | 11 +++++++++++
 arch/x86/kernel/cpu/intel.c      | 32 ++++++++++++++++++--------------
 2 files changed, 29 insertions(+), 14 deletions(-)

diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 1d111350197f..25303194cf5a 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -1092,6 +1092,17 @@
 #define VMX_BASIC_MEM_TYPE_WB	6LLU
 #define VMX_BASIC_INOUT		0x0040000000000000LLU
 
+/* Total Memory Encryption */
+#define MSR_IA32_TME_ACTIVATE			0x982
+#define MSR_IA32_TME_ACTIVATE_LOCKED		BIT(0)
+#define MSR_IA32_TME_ACTIVATE_ENABLED		BIT(1)
+#define MSR_IA32_TME_ACTIVATE_POLICY_OFFSET	4
+#define MSR_IA32_TME_ACTIVATE_POLICY_MASK	0xf
+#define MSR_IA32_TME_ACTIVATE_KEYID_BITS_OFFSET	32
+#define MSR_IA32_TME_ACTIVATE_KEYID_BITS_MASK	0xf
+#define MSR_IA32_TME_ACTIVATE_CRYPTO_ALG_OFFSET	48
+#define MSR_IA32_TME_ACTIVATE_CRYPTO_ALG_MASK	0xffff
+
 /* Resctrl MSRs: */
 /* - Intel: */
 #define MSR_IA32_L3_QOS_CFG		0xc81
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 17240b96ffda..88c95d919061 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -184,31 +184,34 @@ static bool bad_spectre_microcode(struct cpuinfo_x86 *c)
 	return false;
 }
 
-#define MSR_IA32_TME_ACTIVATE		0x982
-
 /* Helpers to access TME_ACTIVATE MSR */
-#define TME_ACTIVATE_LOCKED(x)		(x & 0x1)
-#define TME_ACTIVATE_ENABLED(x)		(x & 0x2)
+#define TME_ACTIVATE_IS_LOCKED(x)	(x & MSR_IA32_TME_ACTIVATE_LOCKED)
+#define TME_ACTIVATE_IS_ENABLED(x)	(x & MSR_IA32_TME_ACTIVATE_ENABLED)
 
-#define TME_ACTIVATE_POLICY(x)		((x >> 4) & 0xf)	/* Bits 7:4 */
+#define TME_ACTIVATE_POLICY(x)	\
+	((x >> MSR_IA32_TME_ACTIVATE_POLICY_OFFSET)	\
+	 & MSR_IA32_TME_ACTIVATE_POLICY_MASK)
 #define TME_ACTIVATE_POLICY_AES_XTS_128	0
 
-#define TME_ACTIVATE_KEYID_BITS(x)	((x >> 32) & 0xf)	/* Bits 35:32 */
+#define TME_ACTIVATE_KEYID_BITS(x)			\
+	((x >> MSR_IA32_TME_ACTIVATE_KEYID_BITS_OFFSET)	\
+	 & MSR_IA32_TME_ACTIVATE_KEYID_BITS_MASK)
 
-#define TME_ACTIVATE_CRYPTO_ALGS(x)	((x >> 48) & 0xffff)	/* Bits 63:48 */
+#define TME_ACTIVATE_CRYPTO_ALGS(x)			\
+	((x >> MSR_IA32_TME_ACTIVATE_CRYPTO_ALG_OFFSET)	\
+	 & MSR_IA32_TME_ACTIVATE_CRYPTO_ALG_MASK)
 #define TME_ACTIVATE_CRYPTO_AES_XTS_128	1
 
-/* Values for mktme_status (SW only construct) */
-#define MKTME_ENABLED			0
-#define MKTME_DISABLED			1
-#define MKTME_UNINITIALIZED		2
-static int mktme_status = MKTME_UNINITIALIZED;
-
 static void detect_tme(struct cpuinfo_x86 *c)
 {
 	u64 tme_activate, tme_policy, tme_crypto_algs;
 	int keyid_bits = 0, nr_keyids = 0;
 	static u64 tme_activate_cpu0 = 0;
+	static enum {
+		MKTME_ENABLED,
+		MKTME_DISABLED,
+		MKTME_UNINITIALIZED
+	} mktme_status = MKTME_UNINITIALIZED;
 
 	rdmsrl(MSR_IA32_TME_ACTIVATE, tme_activate);
 
@@ -225,7 +228,8 @@ static void detect_tme(struct cpuinfo_x86 *c)
 		tme_activate_cpu0 = tme_activate;
 	}
 
-	if (!TME_ACTIVATE_LOCKED(tme_activate) || !TME_ACTIVATE_ENABLED(tme_activate)) {
+	if (!TME_ACTIVATE_IS_LOCKED(tme_activate) ||
+	    !TME_ACTIVATE_IS_ENABLED(tme_activate)) {
 		pr_info_once("x86/tme: not enabled by BIOS\n");
 		mktme_status = MKTME_DISABLED;
 		return;
-- 
2.40.1