x86: Read MSR_ARCH_CAPS immediately after early_microcode_init()

Move MSR_ARCH_CAPS read code from tsx_init() to early_cpu_init(). Because
microcode updates might make them that MSR to appear/have different values
we also must reload it after a microcode update in early_microcode_init().

Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>

xen/arch/x86/cpu/common.c

@@ -299,7 +299,7 @@ static inline u32 phys_pkg_id(u32 cpuid_apic, int index_msb)
 
    WARNING: this function is only called on the BP.  Don't add code here
    that is supposed to run on all CPUs. */
-void __init early_cpu_init(void)
+void __init early_cpu_init(bool verbose)
 {
 	struct cpuinfo_x86 *c = &boot_cpu_data;
 	u32 eax, ebx, ecx, edx;
@@ -320,6 +320,8 @@ void __init early_cpu_init(void)
 	case X86_VENDOR_SHANGHAI: this_cpu = &shanghai_cpu_dev; break;
 	case X86_VENDOR_HYGON:    this_cpu = &hygon_cpu_dev;    break;
 	default:
+		if (!verbose)
+			break;
 		printk(XENLOG_ERR
 		       "Unrecognised or unsupported CPU vendor '%.12s'\n",
 		       c->x86_vendor_id);
@@ -336,10 +338,13 @@ void __init early_cpu_init(void)
 	c->x86_capability[FEATURESET_1d] = edx;
 	c->x86_capability[FEATURESET_1c] = ecx;
 
-	printk(XENLOG_INFO
-	       "CPU Vendor: %s, Family %u (%#x), Model %u (%#x), Stepping %u (raw %08x)\n",
-	       x86_cpuid_vendor_to_str(c->x86_vendor), c->x86, c->x86,
-	       c->x86_model, c->x86_model, c->x86_mask, eax);
+	if (verbose)
+		printk(XENLOG_INFO
+		       "CPU Vendor: %s, Family %u (%#x), "
+		       "Model %u (%#x), Stepping %u (raw %08x)\n",
+		       x86_cpuid_vendor_to_str(c->x86_vendor), c->x86,
+		       c->x86, c->x86_model, c->x86_model, c->x86_mask,
+		       eax);
 
 	if (c->cpuid_level >= 7) {
 		uint32_t max_subleaf;
@@ -348,6 +353,11 @@ void __init early_cpu_init(void)
 			    &c->x86_capability[FEATURESET_7c0],
 			    &c->x86_capability[FEATURESET_7d0]);
 
+		if (test_bit(X86_FEATURE_ARCH_CAPS, c->x86_capability))
+			rdmsr(MSR_ARCH_CAPABILITIES,
+			      c->x86_capability[FEATURESET_m10Al],
+			      c->x86_capability[FEATURESET_m10Ah]);
+
 		if (max_subleaf >= 1)
 			cpuid_count(7, 1, &eax, &ebx, &ecx,
 				    &c->x86_capability[FEATURESET_7d1]);

xen/arch/x86/cpu/microcode/core.c

@@ -887,5 +887,14 @@ int __init early_microcode_init(unsigned long *module_map,
     if ( ucode_mod.mod_end || ucode_blob.size )
         rc = early_microcode_update_cpu();
 
+    /*
+     * Some CPUID leaves and MSRs are only present after microcode updates
+     * on some processors. We take the chance here to make sure what little
+     * state we have already probed is re-probed in order to ensure we do
+     * not use stale values. tsx_init() in particular needs to have up to
+     * date MSR_ARCH_CAPS.
+     */
+    early_cpu_init(false);
+
     return rc;
 }

xen/arch/x86/include/asm/setup.h

@@ -15,7 +15,7 @@ extern uint64_t boot_tsc_stamp;
 
 extern void *stack_start;
 
-void early_cpu_init(void);
+void early_cpu_init(bool verbose);
 void early_time_init(void);
 
 void set_nr_cpu_ids(unsigned int max_cpus);

xen/arch/x86/setup.c

@@ -1214,7 +1214,7 @@ void __init noreturn __start_xen(unsigned long mbi_p)
         panic("Bootloader provided no memory information\n");
 
     /* This must come before e820 code because it sets paddr_bits. */
-    early_cpu_init();
+    early_cpu_init(true);
 
     /* Choose shadow stack early, to set infrastructure up appropriately. */
     if ( !boot_cpu_has(X86_FEATURE_CET_SS) )

xen/arch/x86/tsx.c

@@ -39,25 +39,17 @@ void tsx_init(void)
     static bool __read_mostly once;
 
     /*
-     * This function is first called between microcode being loaded, and CPUID
-     * being scanned generally.  Read into boot_cpu_data.x86_capability[] for
-     * the cpu_has_* bits we care about using here.
+     * This function is first called between microcode being loaded, and
+     * CPUID being scanned generally. early_cpu_init() has already prepared
+     * the feature bits needed here. And early_microcode_init() has ensured
+     * they are not stale after the microcode update.
      */
     if ( unlikely(!once) )
     {
         bool has_rtm_always_abort;
 
         once = true;
 
-        if ( boot_cpu_data.cpuid_level >= 7 )
-            boot_cpu_data.x86_capability[FEATURESET_7d0]
-                = cpuid_count_edx(7, 0);
-
-        if ( cpu_has_arch_caps )
-            rdmsr(MSR_ARCH_CAPABILITIES,
-                  boot_cpu_data.x86_capability[FEATURESET_m10Al],
-                  boot_cpu_data.x86_capability[FEATURESET_m10Ah]);
-
         has_rtm_always_abort = cpu_has_rtm_always_abort;
 
         if ( cpu_has_tsx_ctrl && cpu_has_srbds_ctrl )