[PATCH] x86, apic: Add apic calibration hook.

[PATCH] x86, apic: Add apic calibration hook.

[Alok Kataria]

Add a new function pointer calibrate_apic to x86_platform_ops. On native this
does the usual apic calibration. On VMware's platform we override it with a
routine which gets that information from the hypervisor.

Signed-off-by: Alok N Kataria <akataria@vmware.com>
Cc: H. Peter Anvin <hpa@zytor.com>

Index: linux-x86-tree.git/arch/x86/include/asm/apic.h
===================================================================
--- linux-x86-tree.git.orig/arch/x86/include/asm/apic.h	2010-08-17 15:29:21.000000000 -0700
+++ linux-x86-tree.git/arch/x86/include/asm/apic.h	2010-08-17 15:32:11.000000000 -0700
@@ -238,6 +238,7 @@ extern void setup_boot_APIC_clock(void);
 extern void setup_secondary_APIC_clock(void);
 extern int APIC_init_uniprocessor(void);
 extern void enable_NMI_through_LVT0(void);
+extern unsigned int native_calibrate_apic(void);
 
 /*
  * On 32bit this is mach-xxx local
Index: linux-x86-tree.git/arch/x86/include/asm/x86_init.h
===================================================================
--- linux-x86-tree.git.orig/arch/x86/include/asm/x86_init.h	2010-08-17 15:29:21.000000000 -0700
+++ linux-x86-tree.git/arch/x86/include/asm/x86_init.h	2010-08-18 10:20:21.000000000 -0700
@@ -143,6 +143,7 @@ struct x86_cpuinit_ops {
  * @is_untracked_pat_range	exclude from PAT logic
  * @nmi_init			enable NMI on cpus
  * @i8042_detect		pre-detect if i8042 controller exists
+ * @calibrate_apic:		calibrate APIC bus freq
  */
 struct x86_platform_ops {
 	unsigned long (*calibrate_tsc)(void);
@@ -152,6 +153,7 @@ struct x86_platform_ops {
 	bool (*is_untracked_pat_range)(u64 start, u64 end);
 	void (*nmi_init)(void);
 	int (*i8042_detect)(void);
+	unsigned int (*calibrate_apic)(void);
 };
 
 extern struct x86_init_ops x86_init;
Index: linux-x86-tree.git/arch/x86/kernel/apic/apic.c
===================================================================
--- linux-x86-tree.git.orig/arch/x86/kernel/apic/apic.c	2010-08-17 15:29:21.000000000 -0700
+++ linux-x86-tree.git/arch/x86/kernel/apic/apic.c	2010-08-18 10:20:55.000000000 -0700
@@ -176,7 +176,7 @@ static struct resource lapic_resource = 
 	.flags = IORESOURCE_MEM | IORESOURCE_BUSY,
 };
 
-static unsigned int calibration_result;
+static unsigned int apic_calibration_res;
 
 static int lapic_next_event(unsigned long delta,
 			    struct clock_event_device *evt);
@@ -431,7 +431,7 @@ static void lapic_timer_setup(enum clock
 	switch (mode) {
 	case CLOCK_EVT_MODE_PERIODIC:
 	case CLOCK_EVT_MODE_ONESHOT:
-		__setup_APIC_LVTT(calibration_result,
+		__setup_APIC_LVTT(apic_calibration_res,
 				  mode != CLOCK_EVT_MODE_PERIODIC, 1);
 		break;
 	case CLOCK_EVT_MODE_UNUSED:
@@ -590,13 +590,46 @@ calibrate_by_pmtimer(long deltapm, long 
 	return 0;
 }
 
+static void __init initialize_lapic_clkevt(long delta)
+{
+	/* Calculate the scaled math multiplication factor */
+	lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
+				       lapic_clockevent.shift);
+	lapic_clockevent.max_delta_ns =
+		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
+	lapic_clockevent.min_delta_ns =
+		clockevent_delta2ns(0xF, &lapic_clockevent);
+}
+
 static int __init calibrate_APIC_clock(void)
 {
+	apic_calibration_res = x86_platform.calibrate_apic();
+	if (apic_calibration_res) {
+		struct clock_event_device *levt = &__get_cpu_var(lapic_events);
+		long delta;
+
+		if (lapic_clockevent.mult)
+			return 0;
+
+		delta = (apic_calibration_res * LAPIC_CAL_LOOPS) / APIC_DIVISOR;
+		initialize_lapic_clkevt(delta);
+		levt->features &= ~CLOCK_EVT_FEAT_DUMMY;
+		return 0;
+	} else {
+		pr_warning("Unable to calibrate APIC frequency, "
+			   "disabling apic timer\n");
+		return -1;
+	}
+}
+
+unsigned int __init native_calibrate_apic(void)
+{
 	struct clock_event_device *levt = &__get_cpu_var(lapic_events);
 	void (*real_handler)(struct clock_event_device *dev);
 	unsigned long deltaj;
 	long delta, deltatsc;
 	int pm_referenced = 0;
+	unsigned int calibration_result;
 
 	local_irq_disable();
 
@@ -631,14 +664,7 @@ static int __init calibrate_APIC_clock(v
 	pm_referenced = !calibrate_by_pmtimer(lapic_cal_pm2 - lapic_cal_pm1,
 					&delta, &deltatsc);
 
-	/* Calculate the scaled math multiplication factor */
-	lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
-				       lapic_clockevent.shift);
-	lapic_clockevent.max_delta_ns =
-		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
-	lapic_clockevent.min_delta_ns =
-		clockevent_delta2ns(0xF, &lapic_clockevent);
-
+	initialize_lapic_clkevt(delta);
 	calibration_result = (delta * APIC_DIVISOR) / LAPIC_CAL_LOOPS;
 
 	apic_printk(APIC_VERBOSE, "..... delta %ld\n", delta);
@@ -664,7 +690,7 @@ static int __init calibrate_APIC_clock(v
 	if (calibration_result < (1000000 / HZ)) {
 		local_irq_enable();
 		pr_warning("APIC frequency too slow, disabling apic timer\n");
-		return -1;
+		return 0;
 	}
 
 	levt->features &= ~CLOCK_EVT_FEAT_DUMMY;
@@ -706,10 +732,10 @@ static int __init calibrate_APIC_clock(v
 
 	if (levt->features & CLOCK_EVT_FEAT_DUMMY) {
 		pr_warning("APIC timer disabled due to verification failure\n");
-			return -1;
+			return 0;
 	}
 
-	return 0;
+	return calibration_result;
 }
 
 /*
Index: linux-x86-tree.git/arch/x86/kernel/cpu/vmware.c
===================================================================
--- linux-x86-tree.git.orig/arch/x86/kernel/cpu/vmware.c	2010-08-17 15:29:21.000000000 -0700
+++ linux-x86-tree.git/arch/x86/kernel/cpu/vmware.c	2010-08-18 10:20:21.000000000 -0700
@@ -72,17 +72,33 @@ static unsigned long vmware_get_tsc_khz(
 	return tsc_hz;
 }
 
+static unsigned int vmware_calibrate_apic(void)
+{
+	unsigned int calibration_result;
+	uint32_t eax, ebx, ecx, edx;
+
+	VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
+	BUG_ON(!ecx);
+	calibration_result = ecx / HZ;
+
+	printk(KERN_INFO "APIC bus freq read from hypervisor : %u.%03u MHz\n",
+			 calibration_result / (1000000 / HZ),
+			 calibration_result % (1000000 / HZ));
+	return calibration_result;
+}
+
 static void __init vmware_platform_setup(void)
 {
 	uint32_t eax, ebx, ecx, edx;
 
 	VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
 
-	if (ebx != UINT_MAX)
+	if (ebx != UINT_MAX) {
 		x86_platform.calibrate_tsc = vmware_get_tsc_khz;
-	else
+		x86_platform.calibrate_apic = vmware_calibrate_apic;
+	} else
 		printk(KERN_WARNING
-		       "Failed to get TSC freq from the hypervisor\n");
+		       "Failed to setup VMware hypervisor platform\n");
 }
 
 /*
Index: linux-x86-tree.git/arch/x86/kernel/x86_init.c
===================================================================
--- linux-x86-tree.git.orig/arch/x86/kernel/x86_init.c	2010-08-17 15:29:21.000000000 -0700
+++ linux-x86-tree.git/arch/x86/kernel/x86_init.c	2010-08-17 16:44:20.000000000 -0700
@@ -95,7 +95,8 @@ struct x86_platform_ops x86_platform = {
 	.iommu_shutdown			= iommu_shutdown_noop,
 	.is_untracked_pat_range		= is_ISA_range,
 	.nmi_init			= default_nmi_init,
-	.i8042_detect			= default_i8042_detect
+	.i8042_detect			= default_i8042_detect,
+	.calibrate_apic			= native_calibrate_apic
 };
 
 EXPORT_SYMBOL_GPL(x86_platform);

Re: [PATCH] x86, apic: Add apic calibration hook.

[Alok Kataria]

On Wed, 2010-08-18 at 10:41 -0700, Alok Kataria wrote:
> Add a new function pointer calibrate_apic to x86_platform_ops.

I guess I should move this in init_ops too, anything else that needs to
be changed ? 

Thanks,
Alok

>  On native this
> does the usual apic calibration. On VMware's platform we override it with a
> routine which gets that information from the hypervisor.
> 
> Signed-off-by: Alok N Kataria <akataria@vmware.com>
> Cc: H. Peter Anvin <hpa@zytor.com>
> 
> Index: linux-x86-tree.git/arch/x86/include/asm/apic.h
> ===================================================================
> --- linux-x86-tree.git.orig/arch/x86/include/asm/apic.h	2010-08-17 15:29:21.000000000 -0700
> +++ linux-x86-tree.git/arch/x86/include/asm/apic.h	2010-08-17 15:32:11.000000000 -0700
> @@ -238,6 +238,7 @@ extern void setup_boot_APIC_clock(void);
>  extern void setup_secondary_APIC_clock(void);
>  extern int APIC_init_uniprocessor(void);
>  extern void enable_NMI_through_LVT0(void);
> +extern unsigned int native_calibrate_apic(void);
>  
>  /*
>   * On 32bit this is mach-xxx local
> Index: linux-x86-tree.git/arch/x86/include/asm/x86_init.h
> ===================================================================
> --- linux-x86-tree.git.orig/arch/x86/include/asm/x86_init.h	2010-08-17 15:29:21.000000000 -0700
> +++ linux-x86-tree.git/arch/x86/include/asm/x86_init.h	2010-08-18 10:20:21.000000000 -0700
> @@ -143,6 +143,7 @@ struct x86_cpuinit_ops {
>   * @is_untracked_pat_range	exclude from PAT logic
>   * @nmi_init			enable NMI on cpus
>   * @i8042_detect		pre-detect if i8042 controller exists
> + * @calibrate_apic:		calibrate APIC bus freq
>   */
>  struct x86_platform_ops {
>  	unsigned long (*calibrate_tsc)(void);
> @@ -152,6 +153,7 @@ struct x86_platform_ops {
>  	bool (*is_untracked_pat_range)(u64 start, u64 end);
>  	void (*nmi_init)(void);
>  	int (*i8042_detect)(void);
> +	unsigned int (*calibrate_apic)(void);
>  };
>  
>  extern struct x86_init_ops x86_init;
> Index: linux-x86-tree.git/arch/x86/kernel/apic/apic.c
> ===================================================================
> --- linux-x86-tree.git.orig/arch/x86/kernel/apic/apic.c	2010-08-17 15:29:21.000000000 -0700
> +++ linux-x86-tree.git/arch/x86/kernel/apic/apic.c	2010-08-18 10:20:55.000000000 -0700
> @@ -176,7 +176,7 @@ static struct resource lapic_resource = 
>  	.flags = IORESOURCE_MEM | IORESOURCE_BUSY,
>  };
>  
> -static unsigned int calibration_result;
> +static unsigned int apic_calibration_res;
>  
>  static int lapic_next_event(unsigned long delta,
>  			    struct clock_event_device *evt);
> @@ -431,7 +431,7 @@ static void lapic_timer_setup(enum clock
>  	switch (mode) {
>  	case CLOCK_EVT_MODE_PERIODIC:
>  	case CLOCK_EVT_MODE_ONESHOT:
> -		__setup_APIC_LVTT(calibration_result,
> +		__setup_APIC_LVTT(apic_calibration_res,
>  				  mode != CLOCK_EVT_MODE_PERIODIC, 1);
>  		break;
>  	case CLOCK_EVT_MODE_UNUSED:
> @@ -590,13 +590,46 @@ calibrate_by_pmtimer(long deltapm, long 
>  	return 0;
>  }
>  
> +static void __init initialize_lapic_clkevt(long delta)
> +{
> +	/* Calculate the scaled math multiplication factor */
> +	lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
> +				       lapic_clockevent.shift);
> +	lapic_clockevent.max_delta_ns =
> +		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
> +	lapic_clockevent.min_delta_ns =
> +		clockevent_delta2ns(0xF, &lapic_clockevent);
> +}
> +
>  static int __init calibrate_APIC_clock(void)
>  {
> +	apic_calibration_res = x86_platform.calibrate_apic();
> +	if (apic_calibration_res) {
> +		struct clock_event_device *levt = &__get_cpu_var(lapic_events);
> +		long delta;
> +
> +		if (lapic_clockevent.mult)
> +			return 0;
> +
> +		delta = (apic_calibration_res * LAPIC_CAL_LOOPS) / APIC_DIVISOR;
> +		initialize_lapic_clkevt(delta);
> +		levt->features &= ~CLOCK_EVT_FEAT_DUMMY;
> +		return 0;
> +	} else {
> +		pr_warning("Unable to calibrate APIC frequency, "
> +			   "disabling apic timer\n");
> +		return -1;
> +	}
> +}
> +
> +unsigned int __init native_calibrate_apic(void)
> +{
>  	struct clock_event_device *levt = &__get_cpu_var(lapic_events);
>  	void (*real_handler)(struct clock_event_device *dev);
>  	unsigned long deltaj;
>  	long delta, deltatsc;
>  	int pm_referenced = 0;
> +	unsigned int calibration_result;
>  
>  	local_irq_disable();
>  
> @@ -631,14 +664,7 @@ static int __init calibrate_APIC_clock(v
>  	pm_referenced = !calibrate_by_pmtimer(lapic_cal_pm2 - lapic_cal_pm1,
>  					&delta, &deltatsc);
>  
> -	/* Calculate the scaled math multiplication factor */
> -	lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
> -				       lapic_clockevent.shift);
> -	lapic_clockevent.max_delta_ns =
> -		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
> -	lapic_clockevent.min_delta_ns =
> -		clockevent_delta2ns(0xF, &lapic_clockevent);
> -
> +	initialize_lapic_clkevt(delta);
>  	calibration_result = (delta * APIC_DIVISOR) / LAPIC_CAL_LOOPS;
>  
>  	apic_printk(APIC_VERBOSE, "..... delta %ld\n", delta);
> @@ -664,7 +690,7 @@ static int __init calibrate_APIC_clock(v
>  	if (calibration_result < (1000000 / HZ)) {
>  		local_irq_enable();
>  		pr_warning("APIC frequency too slow, disabling apic timer\n");
> -		return -1;
> +		return 0;
>  	}
>  
>  	levt->features &= ~CLOCK_EVT_FEAT_DUMMY;
> @@ -706,10 +732,10 @@ static int __init calibrate_APIC_clock(v
>  
>  	if (levt->features & CLOCK_EVT_FEAT_DUMMY) {
>  		pr_warning("APIC timer disabled due to verification failure\n");
> -			return -1;
> +			return 0;
>  	}
>  
> -	return 0;
> +	return calibration_result;
>  }
>  
>  /*
> Index: linux-x86-tree.git/arch/x86/kernel/cpu/vmware.c
> ===================================================================
> --- linux-x86-tree.git.orig/arch/x86/kernel/cpu/vmware.c	2010-08-17 15:29:21.000000000 -0700
> +++ linux-x86-tree.git/arch/x86/kernel/cpu/vmware.c	2010-08-18 10:20:21.000000000 -0700
> @@ -72,17 +72,33 @@ static unsigned long vmware_get_tsc_khz(
>  	return tsc_hz;
>  }
>  
> +static unsigned int vmware_calibrate_apic(void)
> +{
> +	unsigned int calibration_result;
> +	uint32_t eax, ebx, ecx, edx;
> +
> +	VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
> +	BUG_ON(!ecx);
> +	calibration_result = ecx / HZ;
> +
> +	printk(KERN_INFO "APIC bus freq read from hypervisor : %u.%03u MHz\n",
> +			 calibration_result / (1000000 / HZ),
> +			 calibration_result % (1000000 / HZ));
> +	return calibration_result;
> +}
> +
>  static void __init vmware_platform_setup(void)
>  {
>  	uint32_t eax, ebx, ecx, edx;
>  
>  	VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
>  
> -	if (ebx != UINT_MAX)
> +	if (ebx != UINT_MAX) {
>  		x86_platform.calibrate_tsc = vmware_get_tsc_khz;
> -	else
> +		x86_platform.calibrate_apic = vmware_calibrate_apic;
> +	} else
>  		printk(KERN_WARNING
> -		       "Failed to get TSC freq from the hypervisor\n");
> +		       "Failed to setup VMware hypervisor platform\n");
>  }
>  
>  /*
> Index: linux-x86-tree.git/arch/x86/kernel/x86_init.c
> ===================================================================
> --- linux-x86-tree.git.orig/arch/x86/kernel/x86_init.c	2010-08-17 15:29:21.000000000 -0700
> +++ linux-x86-tree.git/arch/x86/kernel/x86_init.c	2010-08-17 16:44:20.000000000 -0700
> @@ -95,7 +95,8 @@ struct x86_platform_ops x86_platform = {
>  	.iommu_shutdown			= iommu_shutdown_noop,
>  	.is_untracked_pat_range		= is_ISA_range,
>  	.nmi_init			= default_nmi_init,
> -	.i8042_detect			= default_i8042_detect
> +	.i8042_detect			= default_i8042_detect,
> +	.calibrate_apic			= native_calibrate_apic
>  };
>  
>  EXPORT_SYMBOL_GPL(x86_platform);
> 

Re: [PATCH] x86, apic: Add apic calibration hook.

[Alok Kataria]

Here is the patch which adds this hook in the x86_init_ops.timers
structure.

---
Add a new function ptr calibrate_apic to x86_init_ops structure. On native this
does the usual apic calibration. On VMware's platform we override it with a
routine which gets that information from the hypervisor.

Signed-off-by: Alok N Kataria <akataria@vmware.com>
Cc: H. Peter Anvin <hpa@zytor.com>

Index: linux-x86-tree.git/arch/x86/include/asm/apic.h
===================================================================
--- linux-x86-tree.git.orig/arch/x86/include/asm/apic.h	2010-08-17 15:29:21.000000000 -0700
+++ linux-x86-tree.git/arch/x86/include/asm/apic.h	2010-08-17 15:32:11.000000000 -0700
@@ -238,6 +238,7 @@ extern void setup_boot_APIC_clock(void);
 extern void setup_secondary_APIC_clock(void);
 extern int APIC_init_uniprocessor(void);
 extern void enable_NMI_through_LVT0(void);
+extern unsigned int native_calibrate_apic(void);
 
 /*
  * On 32bit this is mach-xxx local
Index: linux-x86-tree.git/arch/x86/include/asm/x86_init.h
===================================================================
--- linux-x86-tree.git.orig/arch/x86/include/asm/x86_init.h	2010-08-17 15:29:21.000000000 -0700
+++ linux-x86-tree.git/arch/x86/include/asm/x86_init.h	2010-08-18 12:01:35.000000000 -0700
@@ -83,11 +83,13 @@ struct x86_init_paging {
  *				boot cpu
  * @tsc_pre_init:		platform function called before TSC init
  * @timer_init:			initialize the platform timer (default PIT/HPET)
+ * @calibrate_apic:		calibrate APIC bus freq
  */
 struct x86_init_timers {
 	void (*setup_percpu_clockev)(void);
 	void (*tsc_pre_init)(void);
 	void (*timer_init)(void);
+	unsigned int (*calibrate_apic)(void);
 };
 
 /**
Index: linux-x86-tree.git/arch/x86/kernel/apic/apic.c
===================================================================
--- linux-x86-tree.git.orig/arch/x86/kernel/apic/apic.c	2010-08-17 15:29:21.000000000 -0700
+++ linux-x86-tree.git/arch/x86/kernel/apic/apic.c	2010-08-18 12:05:33.000000000 -0700
@@ -176,7 +176,7 @@ static struct resource lapic_resource = 
 	.flags = IORESOURCE_MEM | IORESOURCE_BUSY,
 };
 
-static unsigned int calibration_result;
+static unsigned int apic_calibration_res;
 
 static int lapic_next_event(unsigned long delta,
 			    struct clock_event_device *evt);
@@ -431,7 +431,7 @@ static void lapic_timer_setup(enum clock
 	switch (mode) {
 	case CLOCK_EVT_MODE_PERIODIC:
 	case CLOCK_EVT_MODE_ONESHOT:
-		__setup_APIC_LVTT(calibration_result,
+		__setup_APIC_LVTT(apic_calibration_res,
 				  mode != CLOCK_EVT_MODE_PERIODIC, 1);
 		break;
 	case CLOCK_EVT_MODE_UNUSED:
@@ -590,13 +590,46 @@ calibrate_by_pmtimer(long deltapm, long 
 	return 0;
 }
 
+static void __init initialize_lapic_clkevt(long delta)
+{
+	/* Calculate the scaled math multiplication factor */
+	lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
+				       lapic_clockevent.shift);
+	lapic_clockevent.max_delta_ns =
+		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
+	lapic_clockevent.min_delta_ns =
+		clockevent_delta2ns(0xF, &lapic_clockevent);
+}
+
 static int __init calibrate_APIC_clock(void)
 {
+	apic_calibration_res = x86_init.timers.calibrate_apic();
+	if (apic_calibration_res) {
+		struct clock_event_device *levt = &__get_cpu_var(lapic_events);
+		long delta;
+
+		if (lapic_clockevent.mult)
+			return 0;
+
+		delta = (apic_calibration_res * LAPIC_CAL_LOOPS) / APIC_DIVISOR;
+		initialize_lapic_clkevt(delta);
+		levt->features &= ~CLOCK_EVT_FEAT_DUMMY;
+		return 0;
+	} else {
+		pr_warning("Unable to calibrate APIC frequency, "
+			   "disabling apic timer\n");
+		return -1;
+	}
+}
+
+unsigned int __init native_calibrate_apic(void)
+{
 	struct clock_event_device *levt = &__get_cpu_var(lapic_events);
 	void (*real_handler)(struct clock_event_device *dev);
 	unsigned long deltaj;
 	long delta, deltatsc;
 	int pm_referenced = 0;
+	unsigned int calibration_result;
 
 	local_irq_disable();
 
@@ -631,14 +664,7 @@ static int __init calibrate_APIC_clock(v
 	pm_referenced = !calibrate_by_pmtimer(lapic_cal_pm2 - lapic_cal_pm1,
 					&delta, &deltatsc);
 
-	/* Calculate the scaled math multiplication factor */
-	lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
-				       lapic_clockevent.shift);
-	lapic_clockevent.max_delta_ns =
-		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
-	lapic_clockevent.min_delta_ns =
-		clockevent_delta2ns(0xF, &lapic_clockevent);
-
+	initialize_lapic_clkevt(delta);
 	calibration_result = (delta * APIC_DIVISOR) / LAPIC_CAL_LOOPS;
 
 	apic_printk(APIC_VERBOSE, "..... delta %ld\n", delta);
@@ -664,7 +690,7 @@ static int __init calibrate_APIC_clock(v
 	if (calibration_result < (1000000 / HZ)) {
 		local_irq_enable();
 		pr_warning("APIC frequency too slow, disabling apic timer\n");
-		return -1;
+		return 0;
 	}
 
 	levt->features &= ~CLOCK_EVT_FEAT_DUMMY;
@@ -706,10 +732,10 @@ static int __init calibrate_APIC_clock(v
 
 	if (levt->features & CLOCK_EVT_FEAT_DUMMY) {
 		pr_warning("APIC timer disabled due to verification failure\n");
-			return -1;
+			return 0;
 	}
 
-	return 0;
+	return calibration_result;
 }
 
 /*
Index: linux-x86-tree.git/arch/x86/kernel/cpu/vmware.c
===================================================================
--- linux-x86-tree.git.orig/arch/x86/kernel/cpu/vmware.c	2010-08-17 15:29:21.000000000 -0700
+++ linux-x86-tree.git/arch/x86/kernel/cpu/vmware.c	2010-08-18 12:24:57.000000000 -0700
@@ -72,17 +72,33 @@ static unsigned long vmware_get_tsc_khz(
 	return tsc_hz;
 }
 
+static unsigned int __init vmware_calibrate_apic(void)
+{
+	unsigned int calibration_result;
+	uint32_t eax, ebx, ecx, edx;
+
+	VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
+	BUG_ON(!ecx);
+	calibration_result = ecx / HZ;
+
+	printk(KERN_INFO "APIC bus freq read from hypervisor : %u.%03u MHz\n",
+			 calibration_result / (1000000 / HZ),
+			 calibration_result % (1000000 / HZ));
+	return calibration_result;
+}
+
 static void __init vmware_platform_setup(void)
 {
 	uint32_t eax, ebx, ecx, edx;
 
 	VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
 
-	if (ebx != UINT_MAX)
+	if (ebx != UINT_MAX) {
 		x86_platform.calibrate_tsc = vmware_get_tsc_khz;
-	else
+		x86_init.timers.calibrate_apic = vmware_calibrate_apic;
+	} else
 		printk(KERN_WARNING
-		       "Failed to get TSC freq from the hypervisor\n");
+		       "Failed to setup VMware hypervisor platform\n");
 }
 
 /*
Index: linux-x86-tree.git/arch/x86/kernel/x86_init.c
===================================================================
--- linux-x86-tree.git.orig/arch/x86/kernel/x86_init.c	2010-08-17 15:29:21.000000000 -0700
+++ linux-x86-tree.git/arch/x86/kernel/x86_init.c	2010-08-18 12:00:09.000000000 -0700
@@ -68,6 +68,7 @@ struct x86_init_ops x86_init __initdata 
 		.setup_percpu_clockev	= setup_boot_APIC_clock,
 		.tsc_pre_init		= x86_init_noop,
 		.timer_init		= hpet_time_init,
+		.calibrate_apic		= native_calibrate_apic
 	},
 
 	.iommu = {
@@ -95,7 +96,7 @@ struct x86_platform_ops x86_platform = {
 	.iommu_shutdown			= iommu_shutdown_noop,
 	.is_untracked_pat_range		= is_ISA_range,
 	.nmi_init			= default_nmi_init,
-	.i8042_detect			= default_i8042_detect
+	.i8042_detect			= default_i8042_detect,
 };
 
 EXPORT_SYMBOL_GPL(x86_platform);


On Wed, 2010-08-18 at 10:41 -0700, Alok Kataria wrote:
> Add a new function pointer calibrate_apic to x86_platform_ops. On native this
> does the usual apic calibration. On VMware's platform we override it with a
> routine which gets that information from the hypervisor.
> 
> Signed-off-by: Alok N Kataria <akataria@vmware.com>
> Cc: H. Peter Anvin <hpa@zytor.com>
> 
> Index: linux-x86-tree.git/arch/x86/include/asm/apic.h
> ===================================================================
> --- linux-x86-tree.git.orig/arch/x86/include/asm/apic.h	2010-08-17 15:29:21.000000000 -0700
> +++ linux-x86-tree.git/arch/x86/include/asm/apic.h	2010-08-17 15:32:11.000000000 -0700
> @@ -238,6 +238,7 @@ extern void setup_boot_APIC_clock(void);
>  extern void setup_secondary_APIC_clock(void);
>  extern int APIC_init_uniprocessor(void);
>  extern void enable_NMI_through_LVT0(void);
> +extern unsigned int native_calibrate_apic(void);
>  
>  /*
>   * On 32bit this is mach-xxx local
> Index: linux-x86-tree.git/arch/x86/include/asm/x86_init.h
> ===================================================================
> --- linux-x86-tree.git.orig/arch/x86/include/asm/x86_init.h	2010-08-17 15:29:21.000000000 -0700
> +++ linux-x86-tree.git/arch/x86/include/asm/x86_init.h	2010-08-18 10:20:21.000000000 -0700
> @@ -143,6 +143,7 @@ struct x86_cpuinit_ops {
>   * @is_untracked_pat_range	exclude from PAT logic
>   * @nmi_init			enable NMI on cpus
>   * @i8042_detect		pre-detect if i8042 controller exists
> + * @calibrate_apic:		calibrate APIC bus freq
>   */
>  struct x86_platform_ops {
>  	unsigned long (*calibrate_tsc)(void);
> @@ -152,6 +153,7 @@ struct x86_platform_ops {
>  	bool (*is_untracked_pat_range)(u64 start, u64 end);
>  	void (*nmi_init)(void);
>  	int (*i8042_detect)(void);
> +	unsigned int (*calibrate_apic)(void);
>  };
>  
>  extern struct x86_init_ops x86_init;
> Index: linux-x86-tree.git/arch/x86/kernel/apic/apic.c
> ===================================================================
> --- linux-x86-tree.git.orig/arch/x86/kernel/apic/apic.c	2010-08-17 15:29:21.000000000 -0700
> +++ linux-x86-tree.git/arch/x86/kernel/apic/apic.c	2010-08-18 10:20:55.000000000 -0700
> @@ -176,7 +176,7 @@ static struct resource lapic_resource = 
>  	.flags = IORESOURCE_MEM | IORESOURCE_BUSY,
>  };
>  
> -static unsigned int calibration_result;
> +static unsigned int apic_calibration_res;
>  
>  static int lapic_next_event(unsigned long delta,
>  			    struct clock_event_device *evt);
> @@ -431,7 +431,7 @@ static void lapic_timer_setup(enum clock
>  	switch (mode) {
>  	case CLOCK_EVT_MODE_PERIODIC:
>  	case CLOCK_EVT_MODE_ONESHOT:
> -		__setup_APIC_LVTT(calibration_result,
> +		__setup_APIC_LVTT(apic_calibration_res,
>  				  mode != CLOCK_EVT_MODE_PERIODIC, 1);
>  		break;
>  	case CLOCK_EVT_MODE_UNUSED:
> @@ -590,13 +590,46 @@ calibrate_by_pmtimer(long deltapm, long 
>  	return 0;
>  }
>  
> +static void __init initialize_lapic_clkevt(long delta)
> +{
> +	/* Calculate the scaled math multiplication factor */
> +	lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
> +				       lapic_clockevent.shift);
> +	lapic_clockevent.max_delta_ns =
> +		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
> +	lapic_clockevent.min_delta_ns =
> +		clockevent_delta2ns(0xF, &lapic_clockevent);
> +}
> +
>  static int __init calibrate_APIC_clock(void)
>  {
> +	apic_calibration_res = x86_platform.calibrate_apic();
> +	if (apic_calibration_res) {
> +		struct clock_event_device *levt = &__get_cpu_var(lapic_events);
> +		long delta;
> +
> +		if (lapic_clockevent.mult)
> +			return 0;
> +
> +		delta = (apic_calibration_res * LAPIC_CAL_LOOPS) / APIC_DIVISOR;
> +		initialize_lapic_clkevt(delta);
> +		levt->features &= ~CLOCK_EVT_FEAT_DUMMY;
> +		return 0;
> +	} else {
> +		pr_warning("Unable to calibrate APIC frequency, "
> +			   "disabling apic timer\n");
> +		return -1;
> +	}
> +}
> +
> +unsigned int __init native_calibrate_apic(void)
> +{
>  	struct clock_event_device *levt = &__get_cpu_var(lapic_events);
>  	void (*real_handler)(struct clock_event_device *dev);
>  	unsigned long deltaj;
>  	long delta, deltatsc;
>  	int pm_referenced = 0;
> +	unsigned int calibration_result;
>  
>  	local_irq_disable();
>  
> @@ -631,14 +664,7 @@ static int __init calibrate_APIC_clock(v
>  	pm_referenced = !calibrate_by_pmtimer(lapic_cal_pm2 - lapic_cal_pm1,
>  					&delta, &deltatsc);
>  
> -	/* Calculate the scaled math multiplication factor */
> -	lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
> -				       lapic_clockevent.shift);
> -	lapic_clockevent.max_delta_ns =
> -		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
> -	lapic_clockevent.min_delta_ns =
> -		clockevent_delta2ns(0xF, &lapic_clockevent);
> -
> +	initialize_lapic_clkevt(delta);
>  	calibration_result = (delta * APIC_DIVISOR) / LAPIC_CAL_LOOPS;
>  
>  	apic_printk(APIC_VERBOSE, "..... delta %ld\n", delta);
> @@ -664,7 +690,7 @@ static int __init calibrate_APIC_clock(v
>  	if (calibration_result < (1000000 / HZ)) {
>  		local_irq_enable();
>  		pr_warning("APIC frequency too slow, disabling apic timer\n");
> -		return -1;
> +		return 0;
>  	}
>  
>  	levt->features &= ~CLOCK_EVT_FEAT_DUMMY;
> @@ -706,10 +732,10 @@ static int __init calibrate_APIC_clock(v
>  
>  	if (levt->features & CLOCK_EVT_FEAT_DUMMY) {
>  		pr_warning("APIC timer disabled due to verification failure\n");
> -			return -1;
> +			return 0;
>  	}
>  
> -	return 0;
> +	return calibration_result;
>  }
>  
>  /*
> Index: linux-x86-tree.git/arch/x86/kernel/cpu/vmware.c
> ===================================================================
> --- linux-x86-tree.git.orig/arch/x86/kernel/cpu/vmware.c	2010-08-17 15:29:21.000000000 -0700
> +++ linux-x86-tree.git/arch/x86/kernel/cpu/vmware.c	2010-08-18 10:20:21.000000000 -0700
> @@ -72,17 +72,33 @@ static unsigned long vmware_get_tsc_khz(
>  	return tsc_hz;
>  }
>  
> +static unsigned int vmware_calibrate_apic(void)
> +{
> +	unsigned int calibration_result;
> +	uint32_t eax, ebx, ecx, edx;
> +
> +	VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
> +	BUG_ON(!ecx);
> +	calibration_result = ecx / HZ;
> +
> +	printk(KERN_INFO "APIC bus freq read from hypervisor : %u.%03u MHz\n",
> +			 calibration_result / (1000000 / HZ),
> +			 calibration_result % (1000000 / HZ));
> +	return calibration_result;
> +}
> +
>  static void __init vmware_platform_setup(void)
>  {
>  	uint32_t eax, ebx, ecx, edx;
>  
>  	VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
>  
> -	if (ebx != UINT_MAX)
> +	if (ebx != UINT_MAX) {
>  		x86_platform.calibrate_tsc = vmware_get_tsc_khz;
> -	else
> +		x86_platform.calibrate_apic = vmware_calibrate_apic;
> +	} else
>  		printk(KERN_WARNING
> -		       "Failed to get TSC freq from the hypervisor\n");
> +		       "Failed to setup VMware hypervisor platform\n");
>  }
>  
>  /*
> Index: linux-x86-tree.git/arch/x86/kernel/x86_init.c
> ===================================================================
> --- linux-x86-tree.git.orig/arch/x86/kernel/x86_init.c	2010-08-17 15:29:21.000000000 -0700
> +++ linux-x86-tree.git/arch/x86/kernel/x86_init.c	2010-08-17 16:44:20.000000000 -0700
> @@ -95,7 +95,8 @@ struct x86_platform_ops x86_platform = {
>  	.iommu_shutdown			= iommu_shutdown_noop,
>  	.is_untracked_pat_range		= is_ISA_range,
>  	.nmi_init			= default_nmi_init,
> -	.i8042_detect			= default_i8042_detect
> +	.i8042_detect			= default_i8042_detect,
> +	.calibrate_apic			= native_calibrate_apic
>  };
>  
>  EXPORT_SYMBOL_GPL(x86_platform);
> 

Re: [PATCH] x86, apic: Add apic calibration hook.

[Alok Kataria]

On Wed, 2010-08-18 at 12:27 -0700, Alok Kataria wrote:
> Here is the patch which adds this hook in the x86_init_ops.timers
> structure.
> 
> ---
> Add a new function ptr calibrate_apic to x86_init_ops structure. On native this
> does the usual apic calibration. On VMware's platform we override it with a
> routine which gets that information from the hypervisor.
> 

Any comments on this one ? 

Thanks in advance. 
Alok

> Signed-off-by: Alok N Kataria <akataria@vmware.com>
> Cc: H. Peter Anvin <hpa@zytor.com>
> 
> Index: linux-x86-tree.git/arch/x86/include/asm/apic.h
> ===================================================================
> --- linux-x86-tree.git.orig/arch/x86/include/asm/apic.h	2010-08-17 15:29:21.000000000 -0700
> +++ linux-x86-tree.git/arch/x86/include/asm/apic.h	2010-08-17 15:32:11.000000000 -0700
> @@ -238,6 +238,7 @@ extern void setup_boot_APIC_clock(void);
>  extern void setup_secondary_APIC_clock(void);
>  extern int APIC_init_uniprocessor(void);
>  extern void enable_NMI_through_LVT0(void);
> +extern unsigned int native_calibrate_apic(void);
>  
>  /*
>   * On 32bit this is mach-xxx local
> Index: linux-x86-tree.git/arch/x86/include/asm/x86_init.h
> ===================================================================
> --- linux-x86-tree.git.orig/arch/x86/include/asm/x86_init.h	2010-08-17 15:29:21.000000000 -0700
> +++ linux-x86-tree.git/arch/x86/include/asm/x86_init.h	2010-08-18 12:01:35.000000000 -0700
> @@ -83,11 +83,13 @@ struct x86_init_paging {
>   *				boot cpu
>   * @tsc_pre_init:		platform function called before TSC init
>   * @timer_init:			initialize the platform timer (default PIT/HPET)
> + * @calibrate_apic:		calibrate APIC bus freq
>   */
>  struct x86_init_timers {
>  	void (*setup_percpu_clockev)(void);
>  	void (*tsc_pre_init)(void);
>  	void (*timer_init)(void);
> +	unsigned int (*calibrate_apic)(void);
>  };
>  
>  /**
> Index: linux-x86-tree.git/arch/x86/kernel/apic/apic.c
> ===================================================================
> --- linux-x86-tree.git.orig/arch/x86/kernel/apic/apic.c	2010-08-17 15:29:21.000000000 -0700
> +++ linux-x86-tree.git/arch/x86/kernel/apic/apic.c	2010-08-18 12:05:33.000000000 -0700
> @@ -176,7 +176,7 @@ static struct resource lapic_resource = 
>  	.flags = IORESOURCE_MEM | IORESOURCE_BUSY,
>  };
>  
> -static unsigned int calibration_result;
> +static unsigned int apic_calibration_res;
>  
>  static int lapic_next_event(unsigned long delta,
>  			    struct clock_event_device *evt);
> @@ -431,7 +431,7 @@ static void lapic_timer_setup(enum clock
>  	switch (mode) {
>  	case CLOCK_EVT_MODE_PERIODIC:
>  	case CLOCK_EVT_MODE_ONESHOT:
> -		__setup_APIC_LVTT(calibration_result,
> +		__setup_APIC_LVTT(apic_calibration_res,
>  				  mode != CLOCK_EVT_MODE_PERIODIC, 1);
>  		break;
>  	case CLOCK_EVT_MODE_UNUSED:
> @@ -590,13 +590,46 @@ calibrate_by_pmtimer(long deltapm, long 
>  	return 0;
>  }
>  
> +static void __init initialize_lapic_clkevt(long delta)
> +{
> +	/* Calculate the scaled math multiplication factor */
> +	lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
> +				       lapic_clockevent.shift);
> +	lapic_clockevent.max_delta_ns =
> +		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
> +	lapic_clockevent.min_delta_ns =
> +		clockevent_delta2ns(0xF, &lapic_clockevent);
> +}
> +
>  static int __init calibrate_APIC_clock(void)
>  {
> +	apic_calibration_res = x86_init.timers.calibrate_apic();
> +	if (apic_calibration_res) {
> +		struct clock_event_device *levt = &__get_cpu_var(lapic_events);
> +		long delta;
> +
> +		if (lapic_clockevent.mult)
> +			return 0;
> +
> +		delta = (apic_calibration_res * LAPIC_CAL_LOOPS) / APIC_DIVISOR;
> +		initialize_lapic_clkevt(delta);
> +		levt->features &= ~CLOCK_EVT_FEAT_DUMMY;
> +		return 0;
> +	} else {
> +		pr_warning("Unable to calibrate APIC frequency, "
> +			   "disabling apic timer\n");
> +		return -1;
> +	}
> +}
> +
> +unsigned int __init native_calibrate_apic(void)
> +{
>  	struct clock_event_device *levt = &__get_cpu_var(lapic_events);
>  	void (*real_handler)(struct clock_event_device *dev);
>  	unsigned long deltaj;
>  	long delta, deltatsc;
>  	int pm_referenced = 0;
> +	unsigned int calibration_result;
>  
>  	local_irq_disable();
>  
> @@ -631,14 +664,7 @@ static int __init calibrate_APIC_clock(v
>  	pm_referenced = !calibrate_by_pmtimer(lapic_cal_pm2 - lapic_cal_pm1,
>  					&delta, &deltatsc);
>  
> -	/* Calculate the scaled math multiplication factor */
> -	lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
> -				       lapic_clockevent.shift);
> -	lapic_clockevent.max_delta_ns =
> -		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
> -	lapic_clockevent.min_delta_ns =
> -		clockevent_delta2ns(0xF, &lapic_clockevent);
> -
> +	initialize_lapic_clkevt(delta);
>  	calibration_result = (delta * APIC_DIVISOR) / LAPIC_CAL_LOOPS;
>  
>  	apic_printk(APIC_VERBOSE, "..... delta %ld\n", delta);
> @@ -664,7 +690,7 @@ static int __init calibrate_APIC_clock(v
>  	if (calibration_result < (1000000 / HZ)) {
>  		local_irq_enable();
>  		pr_warning("APIC frequency too slow, disabling apic timer\n");
> -		return -1;
> +		return 0;
>  	}
>  
>  	levt->features &= ~CLOCK_EVT_FEAT_DUMMY;
> @@ -706,10 +732,10 @@ static int __init calibrate_APIC_clock(v
>  
>  	if (levt->features & CLOCK_EVT_FEAT_DUMMY) {
>  		pr_warning("APIC timer disabled due to verification failure\n");
> -			return -1;
> +			return 0;
>  	}
>  
> -	return 0;
> +	return calibration_result;
>  }
>  
>  /*
> Index: linux-x86-tree.git/arch/x86/kernel/cpu/vmware.c
> ===================================================================
> --- linux-x86-tree.git.orig/arch/x86/kernel/cpu/vmware.c	2010-08-17 15:29:21.000000000 -0700
> +++ linux-x86-tree.git/arch/x86/kernel/cpu/vmware.c	2010-08-18 12:24:57.000000000 -0700
> @@ -72,17 +72,33 @@ static unsigned long vmware_get_tsc_khz(
>  	return tsc_hz;
>  }
>  
> +static unsigned int __init vmware_calibrate_apic(void)
> +{
> +	unsigned int calibration_result;
> +	uint32_t eax, ebx, ecx, edx;
> +
> +	VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
> +	BUG_ON(!ecx);
> +	calibration_result = ecx / HZ;
> +
> +	printk(KERN_INFO "APIC bus freq read from hypervisor : %u.%03u MHz\n",
> +			 calibration_result / (1000000 / HZ),
> +			 calibration_result % (1000000 / HZ));
> +	return calibration_result;
> +}
> +
>  static void __init vmware_platform_setup(void)
>  {
>  	uint32_t eax, ebx, ecx, edx;
>  
>  	VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
>  
> -	if (ebx != UINT_MAX)
> +	if (ebx != UINT_MAX) {
>  		x86_platform.calibrate_tsc = vmware_get_tsc_khz;
> -	else
> +		x86_init.timers.calibrate_apic = vmware_calibrate_apic;
> +	} else
>  		printk(KERN_WARNING
> -		       "Failed to get TSC freq from the hypervisor\n");
> +		       "Failed to setup VMware hypervisor platform\n");
>  }
>  
>  /*
> Index: linux-x86-tree.git/arch/x86/kernel/x86_init.c
> ===================================================================
> --- linux-x86-tree.git.orig/arch/x86/kernel/x86_init.c	2010-08-17 15:29:21.000000000 -0700
> +++ linux-x86-tree.git/arch/x86/kernel/x86_init.c	2010-08-18 12:00:09.000000000 -0700
> @@ -68,6 +68,7 @@ struct x86_init_ops x86_init __initdata 
>  		.setup_percpu_clockev	= setup_boot_APIC_clock,
>  		.tsc_pre_init		= x86_init_noop,
>  		.timer_init		= hpet_time_init,
> +		.calibrate_apic		= native_calibrate_apic
>  	},
>  
>  	.iommu = {
> @@ -95,7 +96,7 @@ struct x86_platform_ops x86_platform = {
>  	.iommu_shutdown			= iommu_shutdown_noop,
>  	.is_untracked_pat_range		= is_ISA_range,
>  	.nmi_init			= default_nmi_init,
> -	.i8042_detect			= default_i8042_detect
> +	.i8042_detect			= default_i8042_detect,
>  };
>  
>  EXPORT_SYMBOL_GPL(x86_platform);
> 
> 
> On Wed, 2010-08-18 at 10:41 -0700, Alok Kataria wrote:
> > Add a new function pointer calibrate_apic to x86_platform_ops. On native this
> > does the usual apic calibration. On VMware's platform we override it with a
> > routine which gets that information from the hypervisor.
> > 
> > Signed-off-by: Alok N Kataria <akataria@vmware.com>
> > Cc: H. Peter Anvin <hpa@zytor.com>
> > 
> > Index: linux-x86-tree.git/arch/x86/include/asm/apic.h
> > ===================================================================
> > --- linux-x86-tree.git.orig/arch/x86/include/asm/apic.h	2010-08-17 15:29:21.000000000 -0700
> > +++ linux-x86-tree.git/arch/x86/include/asm/apic.h	2010-08-17 15:32:11.000000000 -0700
> > @@ -238,6 +238,7 @@ extern void setup_boot_APIC_clock(void);
> >  extern void setup_secondary_APIC_clock(void);
> >  extern int APIC_init_uniprocessor(void);
> >  extern void enable_NMI_through_LVT0(void);
> > +extern unsigned int native_calibrate_apic(void);
> >  
> >  /*
> >   * On 32bit this is mach-xxx local
> > Index: linux-x86-tree.git/arch/x86/include/asm/x86_init.h
> > ===================================================================
> > --- linux-x86-tree.git.orig/arch/x86/include/asm/x86_init.h	2010-08-17 15:29:21.000000000 -0700
> > +++ linux-x86-tree.git/arch/x86/include/asm/x86_init.h	2010-08-18 10:20:21.000000000 -0700
> > @@ -143,6 +143,7 @@ struct x86_cpuinit_ops {
> >   * @is_untracked_pat_range	exclude from PAT logic
> >   * @nmi_init			enable NMI on cpus
> >   * @i8042_detect		pre-detect if i8042 controller exists
> > + * @calibrate_apic:		calibrate APIC bus freq
> >   */
> >  struct x86_platform_ops {
> >  	unsigned long (*calibrate_tsc)(void);
> > @@ -152,6 +153,7 @@ struct x86_platform_ops {
> >  	bool (*is_untracked_pat_range)(u64 start, u64 end);
> >  	void (*nmi_init)(void);
> >  	int (*i8042_detect)(void);
> > +	unsigned int (*calibrate_apic)(void);
> >  };
> >  
> >  extern struct x86_init_ops x86_init;
> > Index: linux-x86-tree.git/arch/x86/kernel/apic/apic.c
> > ===================================================================
> > --- linux-x86-tree.git.orig/arch/x86/kernel/apic/apic.c	2010-08-17 15:29:21.000000000 -0700
> > +++ linux-x86-tree.git/arch/x86/kernel/apic/apic.c	2010-08-18 10:20:55.000000000 -0700
> > @@ -176,7 +176,7 @@ static struct resource lapic_resource = 
> >  	.flags = IORESOURCE_MEM | IORESOURCE_BUSY,
> >  };
> >  
> > -static unsigned int calibration_result;
> > +static unsigned int apic_calibration_res;
> >  
> >  static int lapic_next_event(unsigned long delta,
> >  			    struct clock_event_device *evt);
> > @@ -431,7 +431,7 @@ static void lapic_timer_setup(enum clock
> >  	switch (mode) {
> >  	case CLOCK_EVT_MODE_PERIODIC:
> >  	case CLOCK_EVT_MODE_ONESHOT:
> > -		__setup_APIC_LVTT(calibration_result,
> > +		__setup_APIC_LVTT(apic_calibration_res,
> >  				  mode != CLOCK_EVT_MODE_PERIODIC, 1);
> >  		break;
> >  	case CLOCK_EVT_MODE_UNUSED:
> > @@ -590,13 +590,46 @@ calibrate_by_pmtimer(long deltapm, long 
> >  	return 0;
> >  }
> >  
> > +static void __init initialize_lapic_clkevt(long delta)
> > +{
> > +	/* Calculate the scaled math multiplication factor */
> > +	lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
> > +				       lapic_clockevent.shift);
> > +	lapic_clockevent.max_delta_ns =
> > +		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
> > +	lapic_clockevent.min_delta_ns =
> > +		clockevent_delta2ns(0xF, &lapic_clockevent);
> > +}
> > +
> >  static int __init calibrate_APIC_clock(void)
> >  {
> > +	apic_calibration_res = x86_platform.calibrate_apic();
> > +	if (apic_calibration_res) {
> > +		struct clock_event_device *levt = &__get_cpu_var(lapic_events);
> > +		long delta;
> > +
> > +		if (lapic_clockevent.mult)
> > +			return 0;
> > +
> > +		delta = (apic_calibration_res * LAPIC_CAL_LOOPS) / APIC_DIVISOR;
> > +		initialize_lapic_clkevt(delta);
> > +		levt->features &= ~CLOCK_EVT_FEAT_DUMMY;
> > +		return 0;
> > +	} else {
> > +		pr_warning("Unable to calibrate APIC frequency, "
> > +			   "disabling apic timer\n");
> > +		return -1;
> > +	}
> > +}
> > +
> > +unsigned int __init native_calibrate_apic(void)
> > +{
> >  	struct clock_event_device *levt = &__get_cpu_var(lapic_events);
> >  	void (*real_handler)(struct clock_event_device *dev);
> >  	unsigned long deltaj;
> >  	long delta, deltatsc;
> >  	int pm_referenced = 0;
> > +	unsigned int calibration_result;
> >  
> >  	local_irq_disable();
> >  
> > @@ -631,14 +664,7 @@ static int __init calibrate_APIC_clock(v
> >  	pm_referenced = !calibrate_by_pmtimer(lapic_cal_pm2 - lapic_cal_pm1,
> >  					&delta, &deltatsc);
> >  
> > -	/* Calculate the scaled math multiplication factor */
> > -	lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
> > -				       lapic_clockevent.shift);
> > -	lapic_clockevent.max_delta_ns =
> > -		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
> > -	lapic_clockevent.min_delta_ns =
> > -		clockevent_delta2ns(0xF, &lapic_clockevent);
> > -
> > +	initialize_lapic_clkevt(delta);
> >  	calibration_result = (delta * APIC_DIVISOR) / LAPIC_CAL_LOOPS;
> >  
> >  	apic_printk(APIC_VERBOSE, "..... delta %ld\n", delta);
> > @@ -664,7 +690,7 @@ static int __init calibrate_APIC_clock(v
> >  	if (calibration_result < (1000000 / HZ)) {
> >  		local_irq_enable();
> >  		pr_warning("APIC frequency too slow, disabling apic timer\n");
> > -		return -1;
> > +		return 0;
> >  	}
> >  
> >  	levt->features &= ~CLOCK_EVT_FEAT_DUMMY;
> > @@ -706,10 +732,10 @@ static int __init calibrate_APIC_clock(v
> >  
> >  	if (levt->features & CLOCK_EVT_FEAT_DUMMY) {
> >  		pr_warning("APIC timer disabled due to verification failure\n");
> > -			return -1;
> > +			return 0;
> >  	}
> >  
> > -	return 0;
> > +	return calibration_result;
> >  }
> >  
> >  /*
> > Index: linux-x86-tree.git/arch/x86/kernel/cpu/vmware.c
> > ===================================================================
> > --- linux-x86-tree.git.orig/arch/x86/kernel/cpu/vmware.c	2010-08-17 15:29:21.000000000 -0700
> > +++ linux-x86-tree.git/arch/x86/kernel/cpu/vmware.c	2010-08-18 10:20:21.000000000 -0700
> > @@ -72,17 +72,33 @@ static unsigned long vmware_get_tsc_khz(
> >  	return tsc_hz;
> >  }
> >  
> > +static unsigned int vmware_calibrate_apic(void)
> > +{
> > +	unsigned int calibration_result;
> > +	uint32_t eax, ebx, ecx, edx;
> > +
> > +	VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
> > +	BUG_ON(!ecx);
> > +	calibration_result = ecx / HZ;
> > +
> > +	printk(KERN_INFO "APIC bus freq read from hypervisor : %u.%03u MHz\n",
> > +			 calibration_result / (1000000 / HZ),
> > +			 calibration_result % (1000000 / HZ));
> > +	return calibration_result;
> > +}
> > +
> >  static void __init vmware_platform_setup(void)
> >  {
> >  	uint32_t eax, ebx, ecx, edx;
> >  
> >  	VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
> >  
> > -	if (ebx != UINT_MAX)
> > +	if (ebx != UINT_MAX) {
> >  		x86_platform.calibrate_tsc = vmware_get_tsc_khz;
> > -	else
> > +		x86_platform.calibrate_apic = vmware_calibrate_apic;
> > +	} else
> >  		printk(KERN_WARNING
> > -		       "Failed to get TSC freq from the hypervisor\n");
> > +		       "Failed to setup VMware hypervisor platform\n");
> >  }
> >  
> >  /*
> > Index: linux-x86-tree.git/arch/x86/kernel/x86_init.c
> > ===================================================================
> > --- linux-x86-tree.git.orig/arch/x86/kernel/x86_init.c	2010-08-17 15:29:21.000000000 -0700
> > +++ linux-x86-tree.git/arch/x86/kernel/x86_init.c	2010-08-17 16:44:20.000000000 -0700
> > @@ -95,7 +95,8 @@ struct x86_platform_ops x86_platform = {
> >  	.iommu_shutdown			= iommu_shutdown_noop,
> >  	.is_untracked_pat_range		= is_ISA_range,
> >  	.nmi_init			= default_nmi_init,
> > -	.i8042_detect			= default_i8042_detect
> > +	.i8042_detect			= default_i8042_detect,
> > +	.calibrate_apic			= native_calibrate_apic
> >  };
> >  
> >  EXPORT_SYMBOL_GPL(x86_platform);
> > 

Re: [PATCH] x86, apic: Add apic calibration hook.

[Thomas Gleixner]

On Wed, 18 Aug 2010, Alok Kataria wrote:
>  
> +static void __init initialize_lapic_clkevt(long delta)
> +{
> +	/* Calculate the scaled math multiplication factor */
> +	lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
> +				       lapic_clockevent.shift);
> +	lapic_clockevent.max_delta_ns =
> +		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
> +	lapic_clockevent.min_delta_ns =
> +		clockevent_delta2ns(0xF, &lapic_clockevent);
> +}
> +
>  static int __init calibrate_APIC_clock(void)
>  {
> +	apic_calibration_res = x86_init.timers.calibrate_apic();
> +	if (apic_calibration_res) {
> +		struct clock_event_device *levt = &__get_cpu_var(lapic_events);
> +		long delta;
> +
> +		if (lapic_clockevent.mult)
> +			return 0;

  Why is this necessary ? calibrate_APIC_clock() is only called once.

Thanks,

	tglx

Re: [PATCH] x86, apic: Add apic calibration hook.

[Alok Kataria]

Hi Thomas,

Thanks for taking a look.

On Tue, 2010-08-24 at 06:37 -0700, Thomas Gleixner wrote:
> On Wed, 18 Aug 2010, Alok Kataria wrote:
> >  
> > +static void __init initialize_lapic_clkevt(long delta)
> > +{
> > +	/* Calculate the scaled math multiplication factor */
> > +	lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
> > +				       lapic_clockevent.shift);
> > +	lapic_clockevent.max_delta_ns =
> > +		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
> > +	lapic_clockevent.min_delta_ns =
> > +		clockevent_delta2ns(0xF, &lapic_clockevent);
> > +}
> > +
> >  static int __init calibrate_APIC_clock(void)
> >  {
> > +	apic_calibration_res = x86_init.timers.calibrate_apic();
> > +	if (apic_calibration_res) {
> > +		struct clock_event_device *levt = &__get_cpu_var(lapic_events);
> > +		long delta;
> > +
> > +		if (lapic_clockevent.mult)
> > +			return 0;
> 
>   Why is this necessary ? calibrate_APIC_clock() is only called once.
> 

Yes, though timer.calibrate_apci() could behave differently on different
platforms. For eg. the vmware_calibrate_apic doesn't initialize any of
the lapic_clockevent state and we need this to set it up in that case.

Thanks,
Alok

Re: [PATCH] x86, apic: Add apic calibration hook.

[Thomas Gleixner]

Alok,

On Tue, 24 Aug 2010, Alok Kataria wrote:

> Hi Thomas,
> 
> Thanks for taking a look.
> 
> On Tue, 2010-08-24 at 06:37 -0700, Thomas Gleixner wrote:
> > On Wed, 18 Aug 2010, Alok Kataria wrote:
> > >  
> > > +static void __init initialize_lapic_clkevt(long delta)
> > > +{
> > > +	/* Calculate the scaled math multiplication factor */
> > > +	lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
> > > +				       lapic_clockevent.shift);
> > > +	lapic_clockevent.max_delta_ns =
> > > +		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
> > > +	lapic_clockevent.min_delta_ns =
> > > +		clockevent_delta2ns(0xF, &lapic_clockevent);
> > > +}
> > > +
> > >  static int __init calibrate_APIC_clock(void)
> > >  {
> > > +	apic_calibration_res = x86_init.timers.calibrate_apic();
> > > +	if (apic_calibration_res) {
> > > +		struct clock_event_device *levt = &__get_cpu_var(lapic_events);
> > > +		long delta;
> > > +
> > > +		if (lapic_clockevent.mult)
> > > +			return 0;
> > 
> >   Why is this necessary ? calibrate_APIC_clock() is only called once.
> > 
> 
> Yes, though timer.calibrate_apci() could behave differently on different
> platforms. For eg. the vmware_calibrate_apic doesn't initialize any of
> the lapic_clockevent state and we need this to set it up in that case.

Can we please make this consistent ?

Thanks,

	tglx

Re: [PATCH] x86, apic: Add apic calibration hook.

[Alok Kataria]

On Tue, 2010-08-24 at 14:51 -0700, Thomas Gleixner wrote:
> Alok,
> 
> On Tue, 24 Aug 2010, Alok Kataria wrote:
> 
> > Hi Thomas,
> > 
> > Thanks for taking a look.
> > 
> > On Tue, 2010-08-24 at 06:37 -0700, Thomas Gleixner wrote:
> > > On Wed, 18 Aug 2010, Alok Kataria wrote:
> > > >  
> > > > +static void __init initialize_lapic_clkevt(long delta)
> > > > +{
> > > > +	/* Calculate the scaled math multiplication factor */
> > > > +	lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
> > > > +				       lapic_clockevent.shift);
> > > > +	lapic_clockevent.max_delta_ns =
> > > > +		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
> > > > +	lapic_clockevent.min_delta_ns =
> > > > +		clockevent_delta2ns(0xF, &lapic_clockevent);
> > > > +}
> > > > +
> > > >  static int __init calibrate_APIC_clock(void)
> > > >  {
> > > > +	apic_calibration_res = x86_init.timers.calibrate_apic();
> > > > +	if (apic_calibration_res) {
> > > > +		struct clock_event_device *levt = &__get_cpu_var(lapic_events);
> > > > +		long delta;
> > > > +
> > > > +		if (lapic_clockevent.mult)
> > > > +			return 0;
> > > 
> > >   Why is this necessary ? calibrate_APIC_clock() is only called once.
> > > 
> > 
> > Yes, though timer.calibrate_apci() could behave differently on different
> > platforms. For eg. the vmware_calibrate_apic doesn't initialize any of
> > the lapic_clockevent state and we need this to set it up in that case.
> 
> Can we please make this consistent ?

Let me rework this patch and get back in a day or two.

Thanks,
Alok
> 
> Thanks,
> 
> 	tglx

Re: [PATCH] x86, apic: Add apic calibration hook.

[Alok Kataria]

Hi Thomas,

On Tue, 2010-08-24 at 14:58 -0700, Alok Kataria wrote:
> On Tue, 2010-08-24 at 14:51 -0700, Thomas Gleixner wrote:
> > On Tue, 24 Aug 2010, Alok Kataria wrote:
> > > > > +
> > > > > +		if (lapic_clockevent.mult)
> > > > > +			return 0;
> > > > 
> > > >   Why is this necessary ? calibrate_APIC_clock() is only called once.
> > > > 
> > > 
> > > Yes, though timer.calibrate_apci() could behave differently on different
> > > platforms. For eg. the vmware_calibrate_apic doesn't initialize any of
> > > the lapic_clockevent state and we need this to set it up in that case.
> > 
> > Can we please make this consistent ?

How does this patch look ? 

Thanks,
Alok

--

Add apic calibration hook.

From: Alok N Kataria <akataria@vmware.com>

Add a new function ptr calibrate_apic to x86_init_ops structure. On native this
does the usual apic calibration. On VMware's platform we override it with a
routine which gets that information from the hypervisor.

Signed-off-by: Alok N Kataria <akataria@vmware.com>
Cc: H. Peter Anvin <hpa@zytor.com>
---

 arch/x86/include/asm/apic.h     |    6 +++
 arch/x86/include/asm/x86_init.h |    2 +
 arch/x86/kernel/apic/apic.c     |   88 ++++++++++++++++++++-------------------
 arch/x86/kernel/cpu/vmware.c    |   30 ++++++++++++-
 arch/x86/kernel/x86_init.c      |    1 
 5 files changed, 82 insertions(+), 45 deletions(-)


diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 1fa03e0..5012ee5 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -17,6 +17,10 @@
 
 #define ARCH_APICTIMER_STOPS_ON_C3	1
 
+/* Clock divisor */
+#define APIC_DIVISOR	16
+#define LAPIC_CAL_LOOPS	(HZ/10)
+
 /*
  * Debugging macros
  */
@@ -238,6 +242,8 @@ extern void setup_boot_APIC_clock(void);
 extern void setup_secondary_APIC_clock(void);
 extern int APIC_init_uniprocessor(void);
 extern void enable_NMI_through_LVT0(void);
+extern int native_calibrate_apic(void);
+extern int initialize_lapic(long delta, unsigned int calibration_result);
 
 /*
  * On 32bit this is mach-xxx local
diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index baa579c..58f982b 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -83,11 +83,13 @@ struct x86_init_paging {
  *				boot cpu
  * @tsc_pre_init:		platform function called before TSC init
  * @timer_init:			initialize the platform timer (default PIT/HPET)
+ * @calibrate_apic:		calibrate APIC bus freq (ticks per HZ)
  */
 struct x86_init_timers {
 	void (*setup_percpu_clockev)(void);
 	void (*tsc_pre_init)(void);
 	void (*timer_init)(void);
+	int (*calibrate_apic)(void);
 };
 
 /**
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index e3b534c..ca5d084 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -176,7 +176,7 @@ static struct resource lapic_resource = {
 	.flags = IORESOURCE_MEM | IORESOURCE_BUSY,
 };
 
-static unsigned int calibration_result;
+static unsigned int apic_calibration_res;
 
 static int lapic_next_event(unsigned long delta,
 			    struct clock_event_device *evt);
@@ -326,13 +326,6 @@ int lapic_get_maxlvt(void)
 }
 
 /*
- * Local APIC timer
- */
-
-/* Clock divisor */
-#define APIC_DIVISOR 16
-
-/*
  * This function sets up the local APIC timer, with a timeout of
  * 'clocks' APIC bus clock. During calibration we actually call
  * this function twice on the boot CPU, once with a bogus timeout
@@ -431,7 +424,7 @@ static void lapic_timer_setup(enum clock_event_mode mode,
 	switch (mode) {
 	case CLOCK_EVT_MODE_PERIODIC:
 	case CLOCK_EVT_MODE_ONESHOT:
-		__setup_APIC_LVTT(calibration_result,
+		__setup_APIC_LVTT(apic_calibration_res,
 				  mode != CLOCK_EVT_MODE_PERIODIC, 1);
 		break;
 	case CLOCK_EVT_MODE_UNUSED:
@@ -500,8 +493,6 @@ static void __cpuinit setup_APIC_timer(void)
  * back to normal later in the boot process).
  */
 
-#define LAPIC_CAL_LOOPS		(HZ/10)
-
 static __initdata int lapic_cal_loops = -1;
 static __initdata long lapic_cal_t1, lapic_cal_t2;
 static __initdata unsigned long long lapic_cal_tsc1, lapic_cal_tsc2;
@@ -590,13 +581,50 @@ calibrate_by_pmtimer(long deltapm, long *delta, long *deltatsc)
 	return 0;
 }
 
-static int __init calibrate_APIC_clock(void)
+int __init initialize_lapic(long delta, unsigned int calibration_result)
+{
+	struct clock_event_device *levt = &__get_cpu_var(lapic_events);
+
+	/* Calculate the scaled math multiplication factor */
+	lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
+				       lapic_clockevent.shift);
+	lapic_clockevent.max_delta_ns =
+		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
+	lapic_clockevent.min_delta_ns =
+		clockevent_delta2ns(0xF, &lapic_clockevent);
+
+	apic_calibration_res = calibration_result;
+
+	apic_printk(APIC_VERBOSE, "..... delta %ld\n", delta);
+	apic_printk(APIC_VERBOSE, "..... mult: %u\n", lapic_clockevent.mult);
+	apic_printk(APIC_VERBOSE, "..... calibration result: %u\n",
+		    calibration_result);
+
+	apic_printk(APIC_VERBOSE, "..... host bus clock speed is "
+		    "%u.%04u MHz.\n",
+		    calibration_result / (1000000 / HZ),
+		    calibration_result % (1000000 / HZ));
+
+	/*
+	 * Do a sanity check on the APIC calibration result
+	 */
+	if (calibration_result < (1000000 / HZ)) {
+		pr_warning("APIC frequency too slow, disabling apic timer\n");
+		return -1;
+	}
+
+	levt->features &= ~CLOCK_EVT_FEAT_DUMMY;
+	return 0;
+}
+
+int __init native_calibrate_apic(void)
 {
 	struct clock_event_device *levt = &__get_cpu_var(lapic_events);
 	void (*real_handler)(struct clock_event_device *dev);
 	unsigned long deltaj;
 	long delta, deltatsc;
 	int pm_referenced = 0;
+	unsigned int calibration_result;
 
 	local_irq_disable();
 
@@ -631,20 +659,12 @@ static int __init calibrate_APIC_clock(void)
 	pm_referenced = !calibrate_by_pmtimer(lapic_cal_pm2 - lapic_cal_pm1,
 					&delta, &deltatsc);
 
-	/* Calculate the scaled math multiplication factor */
-	lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
-				       lapic_clockevent.shift);
-	lapic_clockevent.max_delta_ns =
-		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
-	lapic_clockevent.min_delta_ns =
-		clockevent_delta2ns(0xF, &lapic_clockevent);
-
 	calibration_result = (delta * APIC_DIVISOR) / LAPIC_CAL_LOOPS;
 
-	apic_printk(APIC_VERBOSE, "..... delta %ld\n", delta);
-	apic_printk(APIC_VERBOSE, "..... mult: %u\n", lapic_clockevent.mult);
-	apic_printk(APIC_VERBOSE, "..... calibration result: %u\n",
-		    calibration_result);
+	if (initialize_lapic(delta, calibration_result)) {
+		local_irq_enable();
+		return -1;
+	}
 
 	if (cpu_has_tsc) {
 		apic_printk(APIC_VERBOSE, "..... CPU clock speed is "
@@ -653,22 +673,6 @@ static int __init calibrate_APIC_clock(void)
 			    (deltatsc / LAPIC_CAL_LOOPS) % (1000000 / HZ));
 	}
 
-	apic_printk(APIC_VERBOSE, "..... host bus clock speed is "
-		    "%u.%04u MHz.\n",
-		    calibration_result / (1000000 / HZ),
-		    calibration_result % (1000000 / HZ));
-
-	/*
-	 * Do a sanity check on the APIC calibration result
-	 */
-	if (calibration_result < (1000000 / HZ)) {
-		local_irq_enable();
-		pr_warning("APIC frequency too slow, disabling apic timer\n");
-		return -1;
-	}
-
-	levt->features &= ~CLOCK_EVT_FEAT_DUMMY;
-
 	/*
 	 * PM timer calibration failed or not turned on
 	 * so lets try APIC timer based calibration
@@ -706,7 +710,7 @@ static int __init calibrate_APIC_clock(void)
 
 	if (levt->features & CLOCK_EVT_FEAT_DUMMY) {
 		pr_warning("APIC timer disabled due to verification failure\n");
-			return -1;
+		return -1;
 	}
 
 	return 0;
@@ -738,7 +742,7 @@ void __init setup_boot_APIC_clock(void)
 	apic_printk(APIC_VERBOSE, "Using local APIC timer interrupts.\n"
 		    "calibrating APIC timer ...\n");
 
-	if (calibrate_APIC_clock()) {
+	if (x86_init.timers.calibrate_apic()) {
 		/* No broadcast on UP ! */
 		if (num_possible_cpus() > 1)
 			setup_APIC_timer();
diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index 227b044..e8b760e 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -26,6 +26,7 @@
 #include <asm/div64.h>
 #include <asm/x86_init.h>
 #include <asm/hypervisor.h>
+#include <asm/apic.h>
 
 #define CPUID_VMWARE_INFO_LEAF	0x40000000
 #define VMWARE_HYPERVISOR_MAGIC	0x564D5868
@@ -72,17 +73,40 @@ static unsigned long vmware_get_tsc_khz(void)
 	return tsc_hz;
 }
 
+static int __init vmware_calibrate_apic(void)
+{
+	unsigned int calibration_result;
+	uint32_t eax, ebx, ecx, edx;
+	int err;
+	long delta;
+	unsigned long flags;
+
+	VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
+	BUG_ON(!ecx);
+	calibration_result = ecx / HZ;
+
+	printk(KERN_INFO "APIC bus freq read from hypervisor\n");
+
+	delta  = (calibration_result * LAPIC_CAL_LOOPS) / APIC_DIVISOR;
+	local_irq_save(flags);
+	err = initialize_lapic(delta, calibration_result);
+	local_irq_restore(flags);
+
+	return err;
+}
+
 static void __init vmware_platform_setup(void)
 {
 	uint32_t eax, ebx, ecx, edx;
 
 	VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
 
-	if (ebx != UINT_MAX)
+	if (ebx != UINT_MAX) {
 		x86_platform.calibrate_tsc = vmware_get_tsc_khz;
-	else
+		x86_init.timers.calibrate_apic = vmware_calibrate_apic;
+	} else
 		printk(KERN_WARNING
-		       "Failed to get TSC freq from the hypervisor\n");
+		       "Failed to setup VMware hypervisor platform\n");
 }
 
 /*
diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
index cd6da6b..f162e14 100644
--- a/arch/x86/kernel/x86_init.c
+++ b/arch/x86/kernel/x86_init.c
@@ -68,6 +68,7 @@ struct x86_init_ops x86_init __initdata = {
 		.setup_percpu_clockev	= setup_boot_APIC_clock,
 		.tsc_pre_init		= x86_init_noop,
 		.timer_init		= hpet_time_init,
+		.calibrate_apic		= native_calibrate_apic
 	},
 
 	.iommu = {

Re: [PATCH] x86, apic: Add apic calibration hook.

[Alok Kataria]

On Fri, 2010-08-27 at 14:28 -0700, Alok Kataria wrote:
> Hi Thomas,
> 
> On Tue, 2010-08-24 at 14:58 -0700, Alok Kataria wrote:
> > On Tue, 2010-08-24 at 14:51 -0700, Thomas Gleixner wrote:
> > > On Tue, 24 Aug 2010, Alok Kataria wrote:
> > > > > > +
> > > > > > +		if (lapic_clockevent.mult)
> > > > > > +			return 0;
> > > > > 
> > > > >   Why is this necessary ? calibrate_APIC_clock() is only called once.
> > > > > 
> > > > 
> > > > Yes, though timer.calibrate_apci() could behave differently on different
> > > > platforms. For eg. the vmware_calibrate_apic doesn't initialize any of
> > > > the lapic_clockevent state and we need this to set it up in that case.
> > > 
> > > Can we please make this consistent ?
> 
> How does this patch look ? 

Thomas, any comments on the patch below, just want to make sure that
this didn't fell through the cracks.

Thanks,
Alok


> --
> 
> Add apic calibration hook.
> 
> From: Alok N Kataria <akataria@vmware.com>
> 
> Add a new function ptr calibrate_apic to x86_init_ops structure. On native this
> does the usual apic calibration. On VMware's platform we override it with a
> routine which gets that information from the hypervisor.
> 
> Signed-off-by: Alok N Kataria <akataria@vmware.com>
> Cc: H. Peter Anvin <hpa@zytor.com>
> ---
> 
>  arch/x86/include/asm/apic.h     |    6 +++
>  arch/x86/include/asm/x86_init.h |    2 +
>  arch/x86/kernel/apic/apic.c     |   88 ++++++++++++++++++++-------------------
>  arch/x86/kernel/cpu/vmware.c    |   30 ++++++++++++-
>  arch/x86/kernel/x86_init.c      |    1 
>  5 files changed, 82 insertions(+), 45 deletions(-)
> 
> 
> diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
> index 1fa03e0..5012ee5 100644
> --- a/arch/x86/include/asm/apic.h
> +++ b/arch/x86/include/asm/apic.h
> @@ -17,6 +17,10 @@
>  
>  #define ARCH_APICTIMER_STOPS_ON_C3	1
>  
> +/* Clock divisor */
> +#define APIC_DIVISOR	16
> +#define LAPIC_CAL_LOOPS	(HZ/10)
> +
>  /*
>   * Debugging macros
>   */
> @@ -238,6 +242,8 @@ extern void setup_boot_APIC_clock(void);
>  extern void setup_secondary_APIC_clock(void);
>  extern int APIC_init_uniprocessor(void);
>  extern void enable_NMI_through_LVT0(void);
> +extern int native_calibrate_apic(void);
> +extern int initialize_lapic(long delta, unsigned int calibration_result);
>  
>  /*
>   * On 32bit this is mach-xxx local
> diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
> index baa579c..58f982b 100644
> --- a/arch/x86/include/asm/x86_init.h
> +++ b/arch/x86/include/asm/x86_init.h
> @@ -83,11 +83,13 @@ struct x86_init_paging {
>   *				boot cpu
>   * @tsc_pre_init:		platform function called before TSC init
>   * @timer_init:			initialize the platform timer (default PIT/HPET)
> + * @calibrate_apic:		calibrate APIC bus freq (ticks per HZ)
>   */
>  struct x86_init_timers {
>  	void (*setup_percpu_clockev)(void);
>  	void (*tsc_pre_init)(void);
>  	void (*timer_init)(void);
> +	int (*calibrate_apic)(void);
>  };
>  
>  /**
> diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
> index e3b534c..ca5d084 100644
> --- a/arch/x86/kernel/apic/apic.c
> +++ b/arch/x86/kernel/apic/apic.c
> @@ -176,7 +176,7 @@ static struct resource lapic_resource = {
>  	.flags = IORESOURCE_MEM | IORESOURCE_BUSY,
>  };
>  
> -static unsigned int calibration_result;
> +static unsigned int apic_calibration_res;
>  
>  static int lapic_next_event(unsigned long delta,
>  			    struct clock_event_device *evt);
> @@ -326,13 +326,6 @@ int lapic_get_maxlvt(void)
>  }
>  
>  /*
> - * Local APIC timer
> - */
> -
> -/* Clock divisor */
> -#define APIC_DIVISOR 16
> -
> -/*
>   * This function sets up the local APIC timer, with a timeout of
>   * 'clocks' APIC bus clock. During calibration we actually call
>   * this function twice on the boot CPU, once with a bogus timeout
> @@ -431,7 +424,7 @@ static void lapic_timer_setup(enum clock_event_mode mode,
>  	switch (mode) {
>  	case CLOCK_EVT_MODE_PERIODIC:
>  	case CLOCK_EVT_MODE_ONESHOT:
> -		__setup_APIC_LVTT(calibration_result,
> +		__setup_APIC_LVTT(apic_calibration_res,
>  				  mode != CLOCK_EVT_MODE_PERIODIC, 1);
>  		break;
>  	case CLOCK_EVT_MODE_UNUSED:
> @@ -500,8 +493,6 @@ static void __cpuinit setup_APIC_timer(void)
>   * back to normal later in the boot process).
>   */
>  
> -#define LAPIC_CAL_LOOPS		(HZ/10)
> -
>  static __initdata int lapic_cal_loops = -1;
>  static __initdata long lapic_cal_t1, lapic_cal_t2;
>  static __initdata unsigned long long lapic_cal_tsc1, lapic_cal_tsc2;
> @@ -590,13 +581,50 @@ calibrate_by_pmtimer(long deltapm, long *delta, long *deltatsc)
>  	return 0;
>  }
>  
> -static int __init calibrate_APIC_clock(void)
> +int __init initialize_lapic(long delta, unsigned int calibration_result)
> +{
> +	struct clock_event_device *levt = &__get_cpu_var(lapic_events);
> +
> +	/* Calculate the scaled math multiplication factor */
> +	lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
> +				       lapic_clockevent.shift);
> +	lapic_clockevent.max_delta_ns =
> +		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
> +	lapic_clockevent.min_delta_ns =
> +		clockevent_delta2ns(0xF, &lapic_clockevent);
> +
> +	apic_calibration_res = calibration_result;
> +
> +	apic_printk(APIC_VERBOSE, "..... delta %ld\n", delta);
> +	apic_printk(APIC_VERBOSE, "..... mult: %u\n", lapic_clockevent.mult);
> +	apic_printk(APIC_VERBOSE, "..... calibration result: %u\n",
> +		    calibration_result);
> +
> +	apic_printk(APIC_VERBOSE, "..... host bus clock speed is "
> +		    "%u.%04u MHz.\n",
> +		    calibration_result / (1000000 / HZ),
> +		    calibration_result % (1000000 / HZ));
> +
> +	/*
> +	 * Do a sanity check on the APIC calibration result
> +	 */
> +	if (calibration_result < (1000000 / HZ)) {
> +		pr_warning("APIC frequency too slow, disabling apic timer\n");
> +		return -1;
> +	}
> +
> +	levt->features &= ~CLOCK_EVT_FEAT_DUMMY;
> +	return 0;
> +}
> +
> +int __init native_calibrate_apic(void)
>  {
>  	struct clock_event_device *levt = &__get_cpu_var(lapic_events);
>  	void (*real_handler)(struct clock_event_device *dev);
>  	unsigned long deltaj;
>  	long delta, deltatsc;
>  	int pm_referenced = 0;
> +	unsigned int calibration_result;
>  
>  	local_irq_disable();
>  
> @@ -631,20 +659,12 @@ static int __init calibrate_APIC_clock(void)
>  	pm_referenced = !calibrate_by_pmtimer(lapic_cal_pm2 - lapic_cal_pm1,
>  					&delta, &deltatsc);
>  
> -	/* Calculate the scaled math multiplication factor */
> -	lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
> -				       lapic_clockevent.shift);
> -	lapic_clockevent.max_delta_ns =
> -		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
> -	lapic_clockevent.min_delta_ns =
> -		clockevent_delta2ns(0xF, &lapic_clockevent);
> -
>  	calibration_result = (delta * APIC_DIVISOR) / LAPIC_CAL_LOOPS;
>  
> -	apic_printk(APIC_VERBOSE, "..... delta %ld\n", delta);
> -	apic_printk(APIC_VERBOSE, "..... mult: %u\n", lapic_clockevent.mult);
> -	apic_printk(APIC_VERBOSE, "..... calibration result: %u\n",
> -		    calibration_result);
> +	if (initialize_lapic(delta, calibration_result)) {
> +		local_irq_enable();
> +		return -1;
> +	}
>  
>  	if (cpu_has_tsc) {
>  		apic_printk(APIC_VERBOSE, "..... CPU clock speed is "
> @@ -653,22 +673,6 @@ static int __init calibrate_APIC_clock(void)
>  			    (deltatsc / LAPIC_CAL_LOOPS) % (1000000 / HZ));
>  	}
>  
> -	apic_printk(APIC_VERBOSE, "..... host bus clock speed is "
> -		    "%u.%04u MHz.\n",
> -		    calibration_result / (1000000 / HZ),
> -		    calibration_result % (1000000 / HZ));
> -
> -	/*
> -	 * Do a sanity check on the APIC calibration result
> -	 */
> -	if (calibration_result < (1000000 / HZ)) {
> -		local_irq_enable();
> -		pr_warning("APIC frequency too slow, disabling apic timer\n");
> -		return -1;
> -	}
> -
> -	levt->features &= ~CLOCK_EVT_FEAT_DUMMY;
> -
>  	/*
>  	 * PM timer calibration failed or not turned on
>  	 * so lets try APIC timer based calibration
> @@ -706,7 +710,7 @@ static int __init calibrate_APIC_clock(void)
>  
>  	if (levt->features & CLOCK_EVT_FEAT_DUMMY) {
>  		pr_warning("APIC timer disabled due to verification failure\n");
> -			return -1;
> +		return -1;
>  	}
>  
>  	return 0;
> @@ -738,7 +742,7 @@ void __init setup_boot_APIC_clock(void)
>  	apic_printk(APIC_VERBOSE, "Using local APIC timer interrupts.\n"
>  		    "calibrating APIC timer ...\n");
>  
> -	if (calibrate_APIC_clock()) {
> +	if (x86_init.timers.calibrate_apic()) {
>  		/* No broadcast on UP ! */
>  		if (num_possible_cpus() > 1)
>  			setup_APIC_timer();
> diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
> index 227b044..e8b760e 100644
> --- a/arch/x86/kernel/cpu/vmware.c
> +++ b/arch/x86/kernel/cpu/vmware.c
> @@ -26,6 +26,7 @@
>  #include <asm/div64.h>
>  #include <asm/x86_init.h>
>  #include <asm/hypervisor.h>
> +#include <asm/apic.h>
>  
>  #define CPUID_VMWARE_INFO_LEAF	0x40000000
>  #define VMWARE_HYPERVISOR_MAGIC	0x564D5868
> @@ -72,17 +73,40 @@ static unsigned long vmware_get_tsc_khz(void)
>  	return tsc_hz;
>  }
>  
> +static int __init vmware_calibrate_apic(void)
> +{
> +	unsigned int calibration_result;
> +	uint32_t eax, ebx, ecx, edx;
> +	int err;
> +	long delta;
> +	unsigned long flags;
> +
> +	VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
> +	BUG_ON(!ecx);
> +	calibration_result = ecx / HZ;
> +
> +	printk(KERN_INFO "APIC bus freq read from hypervisor\n");
> +
> +	delta  = (calibration_result * LAPIC_CAL_LOOPS) / APIC_DIVISOR;
> +	local_irq_save(flags);
> +	err = initialize_lapic(delta, calibration_result);
> +	local_irq_restore(flags);
> +
> +	return err;
> +}
> +
>  static void __init vmware_platform_setup(void)
>  {
>  	uint32_t eax, ebx, ecx, edx;
>  
>  	VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
>  
> -	if (ebx != UINT_MAX)
> +	if (ebx != UINT_MAX) {
>  		x86_platform.calibrate_tsc = vmware_get_tsc_khz;
> -	else
> +		x86_init.timers.calibrate_apic = vmware_calibrate_apic;
> +	} else
>  		printk(KERN_WARNING
> -		       "Failed to get TSC freq from the hypervisor\n");
> +		       "Failed to setup VMware hypervisor platform\n");
>  }
>  
>  /*
> diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
> index cd6da6b..f162e14 100644
> --- a/arch/x86/kernel/x86_init.c
> +++ b/arch/x86/kernel/x86_init.c
> @@ -68,6 +68,7 @@ struct x86_init_ops x86_init __initdata = {
>  		.setup_percpu_clockev	= setup_boot_APIC_clock,
>  		.tsc_pre_init		= x86_init_noop,
>  		.timer_init		= hpet_time_init,
> +		.calibrate_apic		= native_calibrate_apic
>  	},
>  
>  	.iommu = {
>