From: robert <robert@openbsd.org>
Date: Tue, 20 Sep 2022 14:28:27 +0000 (+0000)
Subject: Split out handling of cpu family specific MSRs from cpu_init_msrs()
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=9f172165b574c19186ae3a65383c7fa8c8839f78;p=openbsd

Split out handling of cpu family specific MSRs from cpu_init_msrs()
to a separate function that gets called after identifycpu() so that
we have the required information to handle the correct MSRs for each
cpu.

Additionally, move the handling of the DE_CFG_SERIALIZE_LFENCE and
IA32_DEBUG_INTERFACE_LOCK MSRs out of identifycpu() to the new
function so that they get set again after a suspend/resume cycle as
well, which in fixes TSC sync failures.

discussed with and input from deraadt@, mlarkin@
---

diff --git a/sys/arch/amd64/amd64/acpi_machdep.c b/sys/arch/amd64/amd64/acpi_machdep.c
index db68939ed1e..1d979315716 100644
--- a/sys/arch/amd64/amd64/acpi_machdep.c
+++ b/sys/arch/amd64/amd64/acpi_machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: acpi_machdep.c,v 1.104 2022/08/07 23:56:06 guenther Exp $	*/
+/*	$OpenBSD: acpi_machdep.c,v 1.105 2022/09/20 14:28:27 robert Exp $	*/
 /*
  * Copyright (c) 2005 Thorsten Lockert <tholo@sigmasoft.com>
  *
@@ -456,6 +456,7 @@ void
 acpi_resume_cpu(struct acpi_softc *sc, int state)
 {
 	cpu_init_msrs(&cpu_info_primary);
+	cpu_fix_msrs(&cpu_info_primary);
 
 #if NISA > 0
 	i8259_default_setup();
diff --git a/sys/arch/amd64/amd64/cpu.c b/sys/arch/amd64/amd64/cpu.c
index 8ebd254786f..68c83d902a6 100644
--- a/sys/arch/amd64/amd64/cpu.c
+++ b/sys/arch/amd64/amd64/cpu.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.c,v 1.159 2022/09/15 19:30:51 cheloha Exp $	*/
+/*	$OpenBSD: cpu.c,v 1.160 2022/09/20 14:28:27 robert Exp $	*/
 /* $NetBSD: cpu.c,v 1.1 2003/04/26 18:39:26 fvdl Exp $ */
 
 /*-
@@ -601,6 +601,7 @@ cpu_attach(struct device *parent, struct device *self, void *aux)
 #endif
 		cpu_tsx_disable(ci);
 		identifycpu(ci);
+		cpu_fix_msrs(ci);
 #ifdef MTRR
 		mem_range_attach();
 #endif /* MTRR */
@@ -615,6 +616,7 @@ cpu_attach(struct device *parent, struct device *self, void *aux)
 		    CPUF_PRESENT | CPUF_BSP | CPUF_PRIMARY);
 		cpu_intr_init(ci);
 		identifycpu(ci);
+		cpu_fix_msrs(ci);
 #ifdef MTRR
 		mem_range_attach();
 #endif /* MTRR */
@@ -955,6 +957,9 @@ cpu_hatch(void *v)
 		atomic_setbits_int(&ci->ci_flags, CPUF_IDENTIFIED);
 	}
 
+	/* These have to run after identifycpu() */ 
+	cpu_fix_msrs(ci);
+
 	/*
 	 * Test if our TSC is synchronized for the first time.
 	 * Note that interrupts are off at this point.
@@ -1095,9 +1100,6 @@ extern vector Xsyscall_meltdown, Xsyscall, Xsyscall32;
 void
 cpu_init_msrs(struct cpu_info *ci)
 {
-	uint64_t msr;
-	int family;
-
 	wrmsr(MSR_STAR,
 	    ((uint64_t)GSEL(GCODE_SEL, SEL_KPL) << 32) |
 	    ((uint64_t)GSEL(GUCODE32_SEL, SEL_UPL) << 48));
@@ -1109,18 +1111,60 @@ cpu_init_msrs(struct cpu_info *ci)
 	wrmsr(MSR_FSBASE, 0);
 	wrmsr(MSR_GSBASE, (u_int64_t)ci);
 	wrmsr(MSR_KERNELGSBASE, 0);
+	patinit(ci);
+}
 
-	family = ci->ci_family;
-	if (strcmp(cpu_vendor, "GenuineIntel") == 0 &&
-	    (family > 6 || (family == 6 && ci->ci_model >= 0xd)) &&
-	    rdmsr_safe(MSR_MISC_ENABLE, &msr) == 0 &&
-	    (msr & MISC_ENABLE_FAST_STRINGS) == 0) {
-		msr |= MISC_ENABLE_FAST_STRINGS;
-		wrmsr(MSR_MISC_ENABLE, msr);
-		DPRINTF("%s: enabled fast strings\n", ci->ci_dev->dv_xname);
+void
+cpu_fix_msrs(struct cpu_info *ci)
+{
+	int family = ci->ci_family;
+	uint64_t msr;
+
+	if (!strcmp(cpu_vendor, "GenuineIntel")) {
+		if ((family > 6 || (family == 6 && ci->ci_model >= 0xd)) &&
+		    rdmsr_safe(MSR_MISC_ENABLE, &msr) == 0 &&
+		    (msr & MISC_ENABLE_FAST_STRINGS) == 0) {
+			msr |= MISC_ENABLE_FAST_STRINGS;
+			wrmsr(MSR_MISC_ENABLE, msr);
+			DPRINTF("%s: enabled fast strings\n", ci->ci_dev->dv_xname);
+	
+		/*
+		 * Attempt to disable Silicon Debug and lock the configuration
+		 * if it's enabled and unlocked.
+		 */
+		if (cpu_ecxfeature & CPUIDECX_SDBG) {
+			msr = rdmsr(IA32_DEBUG_INTERFACE);
+			if ((msr & IA32_DEBUG_INTERFACE_ENABLE) &&
+			    (msr & IA32_DEBUG_INTERFACE_LOCK) == 0) {
+				msr &= IA32_DEBUG_INTERFACE_MASK;
+				msr |= IA32_DEBUG_INTERFACE_LOCK;
+				wrmsr(IA32_DEBUG_INTERFACE, msr);
+			} else if (msr & IA32_DEBUG_INTERFACE_ENABLE)
+				printf("%s: cannot disable silicon debug\n",
+				    ci->ci_dev->dv_xname);
+			}
+		}
 	}
 
-	patinit(ci);
+	/*
+	 * "Mitigation G-2" per AMD's Whitepaper "Software Techniques
+	 * for Managing Speculation on AMD Processors"
+	 *
+	 * By setting MSR C001_1029[1]=1, LFENCE becomes a dispatch
+	 * serializing instruction.
+	 *
+	 * This MSR is available on all AMD families >= 10h, except 11h
+	 * where LFENCE is always serializing.
+	 */
+	if (!strcmp(cpu_vendor, "AuthenticAMD")) {
+		if (family >= 0x10 && family != 0x11) {
+			msr = rdmsr(MSR_DE_CFG);
+			if ((msr & DE_CFG_SERIALIZE_LFENCE) == 0) {
+				msr |= DE_CFG_SERIALIZE_LFENCE;
+				wrmsr(MSR_DE_CFG, msr);
+			}
+		}
+	}
 }
 
 void
diff --git a/sys/arch/amd64/amd64/identcpu.c b/sys/arch/amd64/amd64/identcpu.c
index 7cb1d8116fa..09c7ce842fa 100644
--- a/sys/arch/amd64/amd64/identcpu.c
+++ b/sys/arch/amd64/amd64/identcpu.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: identcpu.c,v 1.127 2022/08/30 17:09:21 dv Exp $	*/
+/*	$OpenBSD: identcpu.c,v 1.128 2022/09/20 14:28:27 robert Exp $	*/
 /*	$NetBSD: identcpu.c,v 1.1 2003/04/26 18:39:28 fvdl Exp $	*/
 
 /*
@@ -699,47 +699,6 @@ identifycpu(struct cpu_info *ci)
 	replacemeltdown();
 	x86_print_cacheinfo(ci);
 
-	/*
-	 * "Mitigation G-2" per AMD's Whitepaper "Software Techniques
-	 * for Managing Speculation on AMD Processors"
-	 *
-	 * By setting MSR C001_1029[1]=1, LFENCE becomes a dispatch
-	 * serializing instruction.
-	 *
-	 * This MSR is available on all AMD families >= 10h, except 11h
-	 * where LFENCE is always serializing.
-	 */
-	if (!strcmp(cpu_vendor, "AuthenticAMD")) {
-		if (ci->ci_family >= 0x10 && ci->ci_family != 0x11) {
-			uint64_t msr;
-
-			msr = rdmsr(MSR_DE_CFG);
-			if ((msr & DE_CFG_SERIALIZE_LFENCE) == 0) {
-				msr |= DE_CFG_SERIALIZE_LFENCE;
-				wrmsr(MSR_DE_CFG, msr);
-			}
-		}
-	}
-
-	/*
-	 * Attempt to disable Silicon Debug and lock the configuration
-	 * if it's enabled and unlocked.
-	 */
-	if (!strcmp(cpu_vendor, "GenuineIntel") &&
-	    (cpu_ecxfeature & CPUIDECX_SDBG)) {
-		uint64_t msr;
-
-		msr = rdmsr(IA32_DEBUG_INTERFACE);
-		if ((msr & IA32_DEBUG_INTERFACE_ENABLE) &&
-		    (msr & IA32_DEBUG_INTERFACE_LOCK) == 0) {
-			msr &= IA32_DEBUG_INTERFACE_MASK;
-			msr |= IA32_DEBUG_INTERFACE_LOCK;
-			wrmsr(IA32_DEBUG_INTERFACE, msr);
-		} else if (msr & IA32_DEBUG_INTERFACE_ENABLE)
-			printf("%s: cannot disable silicon debug\n",
-			    ci->ci_dev->dv_xname);
-	}
-
 	if (CPU_IS_PRIMARY(ci)) {
 #ifndef SMALL_KERNEL
 		if (!strcmp(cpu_vendor, "AuthenticAMD") &&
diff --git a/sys/arch/amd64/include/cpu.h b/sys/arch/amd64/include/cpu.h
index 26895056757..1a8c6ddb7b9 100644
--- a/sys/arch/amd64/include/cpu.h
+++ b/sys/arch/amd64/include/cpu.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.h,v 1.150 2022/08/30 17:09:21 dv Exp $	*/
+/*	$OpenBSD: cpu.h,v 1.151 2022/09/20 14:28:27 robert Exp $	*/
 /*	$NetBSD: cpu.h,v 1.1 2003/04/26 18:39:39 fvdl Exp $	*/
 
 /*-
@@ -428,6 +428,7 @@ void	i8254_inittimecounter_simple(void);
 void	i8259_default_setup(void);
 
 void cpu_init_msrs(struct cpu_info *);
+void cpu_fix_msrs(struct cpu_info *);
 void cpu_tsx_disable(struct cpu_info *);
 
 /* dkcsum.c */