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hv: timer: add calibrate tsc hz by cpuid 0x15

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Get tsc hz by cpuid 0x15 if we supported, otherwise
calibrate tsc by pit timer.

Signed-off-by: Li, Fei1 <fei1.li@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
This commit is contained in:
Li, Fei1
2018-04-23 13:24:12 +08:00
committed by Jack Ren
parent cfc87903b2
commit dace32eca1
6 changed files with 50 additions and 21 deletions
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52
hypervisor/arch/x86/timer.c
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@@ -34,7 +34,10 @@
#include <hv_arch.h>
#include <hv_debug.h>
#define MAX_TIMER_ACTIONS 32
#define MAX_TIMER_ACTIONS 32
#define CAL_MS 10
uint64_t tsc_hz = 1000000000;
struct timer {
timer_handle_t func; /* callback if time reached */
@@ -421,21 +424,24 @@ void check_tsc(void)
CPU_CR_WRITE(cr4, (temp64 & ~CR4_TSD));
}
uint64_t tsc_cycles_in_period(uint16_t timer_period_in_us)
static uint64_t pit_calibrate_tsc(uint16_t cal_ms)
{
#define PIT_TICK_RATE 1193182UL
#define PIT_TARGET 0x3FFF
#define PIT_MAX_COUNT 0xFFFF
uint16_t initial_pit;
uint16_t current_pit;
uint32_t current_tsc;
#define PIT_TARGET 0x3FFF
uint16_t max_cal_ms;
uint64_t current_tsc;
if (timer_period_in_us < 1000)
pr_warn("Bad timer_period_in_us: %d\n",
timer_period_in_us);
max_cal_ms = (PIT_MAX_COUNT - PIT_TARGET) * 1000 / PIT_TICK_RATE;
cal_ms = min(cal_ms, max_cal_ms);
/* Assume the 8254 delivers 18.2 ticks per second when 16 bits fully
* wrap. This is about 1.193MHz or a clock period of 0.8384uSec
*/
initial_pit = (uint16_t)(timer_period_in_us*1193000UL/1000000);
initial_pit = (uint16_t)(cal_ms * PIT_TICK_RATE / 1000);
initial_pit += PIT_TARGET;
/* Port 0x43 ==> Control word write; Data 0x30 ==> Select Counter 0,
@@ -444,7 +450,7 @@ uint64_t tsc_cycles_in_period(uint16_t timer_period_in_us)
io_write_byte(0x30, 0x43);
io_write_byte(initial_pit & 0x00ff, 0x40); /* Write LSB */
io_write_byte(initial_pit >> 8, 0x40); /* Write MSB */
io_write_byte(initial_pit >> 8, 0x40); /* Write MSB */
current_tsc = rdtsc();
@@ -461,6 +467,32 @@ uint64_t tsc_cycles_in_period(uint16_t timer_period_in_us)
current_tsc = rdtsc() - current_tsc;
return (uint64_t) current_tsc;
return current_tsc / cal_ms * 1000;
}
/*
* Determine TSC frequency via CPUID 0x15
*/
static uint64_t native_calibrate_tsc(void)
{
if (boot_cpu_data.cpuid_level >= 0x15) {
uint32_t eax_denominator, ebx_numerator, ecx_hz, reserved;
cpuid(0x15, &eax_denominator, &ebx_numerator,
&ecx_hz, &reserved);
if (eax_denominator != 0 && ebx_numerator != 0)
return (uint64_t) ecx_hz *
ebx_numerator / eax_denominator;
}
return 0;
}
void calibrate_tsc(void)
{
tsc_hz = native_calibrate_tsc();
if (!tsc_hz)
tsc_hz = pit_calibrate_tsc(CAL_MS);
printf("%s, tsc_hz=%lu\n", __func__, tsc_hz);
}