Revert "Revert "MFC r327597:""

This reverts commit 38b302a111c25b2ca850c0ce8761761b2c48164a.

5 files changed, 59 insertions, 23 deletions

diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index 3ed29e0..8e508c3 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -1559,7 +1559,7 @@ hammer_time(u_int64_t modulep, u_int64_t physfree)
 
 	kmdp = init_ops.parse_preload_data(modulep);
 
-	identify_cpu();
+	identify_cpu1();
 	identify_hypervisor();
 
 	/* Init basic tunables, hz etc */
diff --git a/sys/dev/cpuctl/cpuctl.c b/sys/dev/cpuctl/cpuctl.c
index 5351d8ed..6a854e4 100644
--- a/sys/dev/cpuctl/cpuctl.c
+++ b/sys/dev/cpuctl/cpuctl.c
@@ -71,6 +71,7 @@ static int cpuctl_do_cpuid(int cpu, cpuctl_cpuid_args_t *data,
     struct thread *td);
 static int cpuctl_do_cpuid_count(int cpu, cpuctl_cpuid_count_args_t *data,
     struct thread *td);
+static int cpuctl_do_eval_cpu_features(int cpu, struct thread *td);
 static int cpuctl_do_update(int cpu, cpuctl_update_args_t *data,
     struct thread *td);
 static int update_intel(int cpu, cpuctl_update_args_t *args,
@@ -157,7 +158,8 @@ cpuctl_ioctl(struct cdev *dev, u_long cmd, caddr_t data,
 	}
 	/* Require write flag for "write" requests. */
 	if ((cmd == CPUCTL_MSRCBIT || cmd == CPUCTL_MSRSBIT ||
-	    cmd == CPUCTL_UPDATE || cmd == CPUCTL_WRMSR) &&
+	    cmd == CPUCTL_UPDATE || cmd == CPUCTL_WRMSR ||
+	    cmd == CPUCTL_EVAL_CPU_FEATURES) &&
 	    (flags & FWRITE) == 0)
 		return (EPERM);
 	switch (cmd) {
@@ -185,6 +187,9 @@ cpuctl_ioctl(struct cdev *dev, u_long cmd, caddr_t data,
 		ret = cpuctl_do_cpuid_count(cpu,
 		    (cpuctl_cpuid_count_args_t *)data, td);
 		break;
+	case CPUCTL_EVAL_CPU_FEATURES:
+		ret = cpuctl_do_eval_cpu_features(cpu, td);
+		break;
 	default:
 		ret = EINVAL;
 		break;
@@ -502,6 +507,29 @@ fail:
 	return (ret);
 }
 
+static int
+cpuctl_do_eval_cpu_features(int cpu, struct thread *td)
+{
+	int is_bound = 0;
+	int oldcpu;
+
+	KASSERT(cpu >= 0 && cpu <= mp_maxid,
+	    ("[cpuctl,%d]: bad cpu number %d", __LINE__, cpu));
+
+#ifdef __i386__
+	if (cpu_id == 0)
+		return (ENODEV);
+#endif
+	oldcpu = td->td_oncpu;
+	is_bound = cpu_sched_is_bound(td);
+	set_cpu(cpu, td);
+	identify_cpu1();
+	identify_cpu2();
+	restore_cpu(oldcpu, is_bound, td);
+	return (0);
+}
+
+
 int
 cpuctl_open(struct cdev *dev, int flags, int fmt __unused, struct thread *td)
 {
diff --git a/sys/sys/cpuctl.h b/sys/sys/cpuctl.h
index 30af524..65556ec 100644
--- a/sys/sys/cpuctl.h
+++ b/sys/sys/cpuctl.h
@@ -57,5 +57,6 @@ typedef struct {
 #define	CPUCTL_MSRSBIT	_IOWR('c', 5, cpuctl_msr_args_t)
 #define	CPUCTL_MSRCBIT	_IOWR('c', 6, cpuctl_msr_args_t)
 #define	CPUCTL_CPUID_COUNT _IOWR('c', 7, cpuctl_cpuid_count_args_t)
+#define	CPUCTL_EVAL_CPU_FEATURES	_IO('c', 8)
 
 #endif /* _CPUCTL_H_ */
diff --git a/sys/x86/include/x86_var.h b/sys/x86/include/x86_var.h
index 7705a1c..ffdf2f0 100644
--- a/sys/x86/include/x86_var.h
+++ b/sys/x86/include/x86_var.h
@@ -116,7 +116,8 @@ void	cpu_setregs(void);
 void	dump_add_page(vm_paddr_t);
 void	dump_drop_page(vm_paddr_t);
 void	finishidentcpu(void);
-void	identify_cpu(void);
+void	identify_cpu1(void);
+void	identify_cpu2(void);
 void	identify_hypervisor(void);
 void	initializecpu(void);
 void	initializecpucache(void);
diff --git a/sys/x86/x86/identcpu.c b/sys/x86/x86/identcpu.c
index c0cc2a6..ab7214c 100644
--- a/sys/x86/x86/identcpu.c
+++ b/sys/x86/x86/identcpu.c
@@ -1370,9 +1370,8 @@ fix_cpuid(void)
 	return (false);
 }
 
-#ifdef __amd64__
 void
-identify_cpu(void)
+identify_cpu1(void)
 {
 	u_int regs[4];
 
@@ -1389,7 +1388,29 @@ identify_cpu(void)
 	cpu_feature = regs[3];
 	cpu_feature2 = regs[2];
 }
-#endif
+
+void
+identify_cpu2(void)
+{
+	u_int regs[4], cpu_stdext_disable;
+
+	if (cpu_high >= 7) {
+		cpuid_count(7, 0, regs);
+		cpu_stdext_feature = regs[1];
+
+		/*
+		 * Some hypervisors failed to filter out unsupported
+		 * extended features.  Allow to disable the
+		 * extensions, activation of which requires setting a
+		 * bit in CR4, and which VM monitors do not support.
+		 */
+		cpu_stdext_disable = 0;
+		TUNABLE_INT_FETCH("hw.cpu_stdext_disable", &cpu_stdext_disable);
+		cpu_stdext_feature &= ~cpu_stdext_disable;
+
+		cpu_stdext_feature2 = regs[2];
+	}
+}
 
 /*
  * Final stage of CPU identification.
@@ -1397,7 +1418,7 @@ identify_cpu(void)
 void
 finishidentcpu(void)
 {
-	u_int regs[4], cpu_stdext_disable;
+	u_int regs[4];
 #ifdef __i386__
 	u_char ccr3;
 #endif
@@ -1416,22 +1437,7 @@ finishidentcpu(void)
 		cpu_mon_max_size = regs[1] &  CPUID5_MON_MAX_SIZE;
 	}
 
-	if (cpu_high >= 7) {
-		cpuid_count(7, 0, regs);
-		cpu_stdext_feature = regs[1];
-
-		/*
-		 * Some hypervisors failed to filter out unsupported
-		 * extended features.  Allow to disable the
-		 * extensions, activation of which requires setting a
-		 * bit in CR4, and which VM monitors do not support.
-		 */
-		cpu_stdext_disable = 0;
-		TUNABLE_INT_FETCH("hw.cpu_stdext_disable", &cpu_stdext_disable);
-		cpu_stdext_feature &= ~cpu_stdext_disable;
-
-		cpu_stdext_feature2 = regs[2];
-	}
+	identify_cpu2();
 
 #ifdef __i386__
 	if (cpu_high > 0 &&