linux-kernel - [RFC][PATCH 32/34] x86/cpu/amd: Move memory encryption detection

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Message-Id: <20240222184008.9A33B01E@davehans-spike.ostc.intel.com>
Date: Thu, 22 Feb 2024 10:40:08 -0800
From: Dave Hansen <dave.hansen@...ux.intel.com>
To: linux-kernel@...r.kernel.org
Cc: kirill.shutemov@...ux.intel.com,pbonzini@...hat.com,tglx@...utronix.de,x86@...nel.org,bp@...en8.de,Dave Hansen <dave.hansen@...ux.intel.com>
Subject: [RFC][PATCH 32/34] x86/cpu/amd: Move memory encryption detection


From: Dave Hansen <dave.hansen@...ux.intel.com>

Right now the AMD memory encryption detection code is run on every CPU
despite it operating on 'bsp_addr_config' and doing setup_clear_cpu_cap()
which only affects 'boot_cpu_data'.

Move it to bsp_init_amd() where it belongs and change its name to match.

Signed-off-by: Dave Hansen <dave.hansen@...ux.intel.com>
---

 b/arch/x86/kernel/cpu/amd.c |  110 ++++++++++++++++++++++----------------------
 1 file changed, 55 insertions(+), 55 deletions(-)

diff -puN arch/x86/kernel/cpu/amd.c~early_init_amd-__init arch/x86/kernel/cpu/amd.c
--- a/arch/x86/kernel/cpu/amd.c~early_init_amd-__init	2024-02-22 10:09:04.201071279 -0800
+++ b/arch/x86/kernel/cpu/amd.c	2024-02-22 10:09:04.201071279 -0800
@@ -468,8 +468,62 @@ static void early_init_amd_mc(struct cpu
 #endif
 }
 
-static void bsp_init_amd(struct cpuinfo_x86 *c)
+static void bsp_detect_mem_encrypt(struct cpuinfo_x86 *c)
 {
+	u64 msr;
+
+	/*
+	 * BIOS support is required for SME and SEV.
+	 *   For SME: If BIOS has enabled SME then adjust x86_phys_bits by
+	 *	      the SME physical address space reduction value.
+	 *	      If BIOS has not enabled SME then don't advertise the
+	 *	      SME feature (set in scattered.c).
+	 *	      If the kernel has not enabled SME via any means then
+	 *	      don't advertise the SME feature.
+	 *   For SEV: If BIOS has not enabled SEV then don't advertise the
+	 *            SEV and SEV_ES feature (set in scattered.c).
+	 *
+	 *   In all cases, since support for SME and SEV requires long mode,
+	 *   don't advertise the feature under CONFIG_X86_32.
+	 */
+	if (cpu_has(c, X86_FEATURE_SME) || cpu_has(c, X86_FEATURE_SEV)) {
+		/* Check if memory encryption is enabled */
+		rdmsrl(MSR_AMD64_SYSCFG, msr);
+		if (!(msr & MSR_AMD64_SYSCFG_MEM_ENCRYPT))
+			goto clear_all;
+
+		/*
+		 * Always adjust physical address bits. Even though this
+		 * will be a value above 32-bits this is still done for
+		 * CONFIG_X86_32 so that accurate values are reported.
+		 */
+		bsp_addr_config.phys_addr_reduction_bits =
+			(cpuid_ebx(0x8000001f) >> 6) & 0x3f;
+
+		if (IS_ENABLED(CONFIG_X86_32))
+			goto clear_all;
+
+		if (!sme_me_mask)
+			setup_clear_cpu_cap(X86_FEATURE_SME);
+
+		rdmsrl(MSR_K7_HWCR, msr);
+		if (!(msr & MSR_K7_HWCR_SMMLOCK))
+			goto clear_sev;
+
+		return;
+
+clear_all:
+		setup_clear_cpu_cap(X86_FEATURE_SME);
+clear_sev:
+		setup_clear_cpu_cap(X86_FEATURE_SEV);
+		setup_clear_cpu_cap(X86_FEATURE_SEV_ES);
+	}
+}
+
+static void __init bsp_init_amd(struct cpuinfo_x86 *c)
+{
+	bsp_detect_mem_encrypt(c);
+
 	if (cpu_has(c, X86_FEATURE_CONSTANT_TSC)) {
 
 		if (c->x86 > 0x10 ||
@@ -593,58 +647,6 @@ warn:
 	WARN_ONCE(1, "Family 0x%x, model: 0x%x??\n", c->x86, c->x86_model);
 }
 
-static void early_detect_mem_encrypt(struct cpuinfo_x86 *c)
-{
-	u64 msr;
-
-	/*
-	 * BIOS support is required for SME and SEV.
-	 *   For SME: If BIOS has enabled SME then adjust x86_phys_bits by
-	 *	      the SME physical address space reduction value.
-	 *	      If BIOS has not enabled SME then don't advertise the
-	 *	      SME feature (set in scattered.c).
-	 *	      If the kernel has not enabled SME via any means then
-	 *	      don't advertise the SME feature.
-	 *   For SEV: If BIOS has not enabled SEV then don't advertise the
-	 *            SEV and SEV_ES feature (set in scattered.c).
-	 *
-	 *   In all cases, since support for SME and SEV requires long mode,
-	 *   don't advertise the feature under CONFIG_X86_32.
-	 */
-	if (cpu_has(c, X86_FEATURE_SME) || cpu_has(c, X86_FEATURE_SEV)) {
-		/* Check if memory encryption is enabled */
-		rdmsrl(MSR_AMD64_SYSCFG, msr);
-		if (!(msr & MSR_AMD64_SYSCFG_MEM_ENCRYPT))
-			goto clear_all;
-
-		/*
-		 * Always adjust physical address bits. Even though this
-		 * will be a value above 32-bits this is still done for
-		 * CONFIG_X86_32 so that accurate values are reported.
-		 */
-		bsp_addr_config.phys_addr_reduction_bits =
-			(cpuid_ebx(0x8000001f) >> 6) & 0x3f;
-
-		if (IS_ENABLED(CONFIG_X86_32))
-			goto clear_all;
-
-		if (!sme_me_mask)
-			setup_clear_cpu_cap(X86_FEATURE_SME);
-
-		rdmsrl(MSR_K7_HWCR, msr);
-		if (!(msr & MSR_K7_HWCR_SMMLOCK))
-			goto clear_sev;
-
-		return;
-
-clear_all:
-		setup_clear_cpu_cap(X86_FEATURE_SME);
-clear_sev:
-		setup_clear_cpu_cap(X86_FEATURE_SEV);
-		setup_clear_cpu_cap(X86_FEATURE_SEV_ES);
-	}
-}
-
 static void early_init_amd(struct cpuinfo_x86 *c)
 {
 	u64 value;
@@ -715,8 +717,6 @@ static void early_init_amd(struct cpuinf
 	if (c->x86 == 0x16 && c->x86_model <= 0xf)
 		msr_set_bit(MSR_AMD64_LS_CFG, 15);
 
-	early_detect_mem_encrypt(c);
-
 	/* Re-enable TopologyExtensions if switched off by BIOS */
 	if (c->x86 == 0x15 &&
 	    (c->x86_model >= 0x10 && c->x86_model <= 0x6f) &&
_