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hyperv: Implement "enlightened" time counter, which is rdtsc based.

Browse Source 
Reviewed by:	kib
MFC after:	1 week
Sponsored by:	Microsoft
Differential Revision:	https://reviews.freebsd.org/D8763
This commit is contained in:
Sepherosa Ziehau 2016-12-14 03:20:57 +00:00
parent 82fe834050
commit de69dfbbbc
3 changed files with 129 additions and 0 deletions
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1
sys/dev/hyperv/include/hyperv.h
View File

@ -45,6 +45,7 @@
#define CPUID_HV_MSR_HYPERCALL 0x0020 /* MSR_HV_GUEST_OS_ID
* MSR_HV_HYPERCALL */
#define CPUID_HV_MSR_VP_INDEX 0x0040 /* MSR_HV_VP_INDEX */
#define CPUID_HV_MSR_REFERENCE_TSC 0x0200 /* MSR_HV_REFERENCE_TSC */
#define CPUID_HV_MSR_GUEST_IDLE 0x0400 /* MSR_HV_GUEST_IDLE */
#ifndef NANOSEC

112
sys/dev/hyperv/vmbus/amd64/hyperv_machdep.c
View File

@ -28,7 +28,37 @@
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/timetc.h>
#include <machine/cpufunc.h>
#include <machine/cputypes.h>
#include <machine/md_var.h>
#include <dev/hyperv/include/hyperv.h>
#include <dev/hyperv/include/hyperv_busdma.h>
#include <dev/hyperv/vmbus/hyperv_machdep.h>
#include <dev/hyperv/vmbus/hyperv_reg.h>
#include <dev/hyperv/vmbus/hyperv_var.h>
struct hyperv_reftsc_ctx {
struct hyperv_reftsc *tsc_ref;
struct hyperv_dma tsc_ref_dma;
};
static struct timecounter hyperv_tsc_timecounter = {
.tc_get_timecount = NULL, /* based on CPU vendor. */
.tc_poll_pps = NULL,
.tc_counter_mask = 0xffffffff,
.tc_frequency = HYPERV_TIMER_FREQ,
.tc_name = "Hyper-V-TSC",
.tc_quality = 3000,
.tc_flags = 0,
.tc_priv = NULL
};
static struct hyperv_reftsc_ctx hyperv_ref_tsc;
uint64_t
hypercall_md(volatile void *hc_addr, uint64_t in_val,
@ -41,3 +71,85 @@ hypercall_md(volatile void *hc_addr, uint64_t in_val,
"c" (in_val), "d" (in_paddr), "m" (hc_addr));
return (status);
}
#define HYPERV_TSC_TIMECOUNT(fence) \
static u_int \
hyperv_tsc_timecount_##fence(struct timecounter *tc) \
{ \
struct hyperv_reftsc *tsc_ref = hyperv_ref_tsc.tsc_ref; \
uint32_t seq; \
\
while ((seq = atomic_load_acq_int(&tsc_ref->tsc_seq)) != 0) { \
uint64_t disc, ret, tsc; \
uint64_t scale = tsc_ref->tsc_scale; \
int64_t ofs = tsc_ref->tsc_ofs; \
\
fence(); \
tsc = rdtsc(); \
\
/* ret = ((tsc * scale) >> 64) + ofs */ \
__asm__ __volatile__ ("mulq %3" : \
"=d" (ret), "=a" (disc) : \
"a" (tsc), "r" (scale)); \
ret += ofs; \
\
atomic_thread_fence_acq(); \
if (tsc_ref->tsc_seq == seq) \
return (ret); \
\
/* Sequence changed; re-sync. */ \
} \
/* Fallback to the generic timecounter, i.e. rdmsr. */ \
return (rdmsr(MSR_HV_TIME_REF_COUNT)); \
} \
struct __hack
HYPERV_TSC_TIMECOUNT(lfence);
HYPERV_TSC_TIMECOUNT(mfence);
static void
hyperv_tsc_tcinit(void *dummy __unused)
{
uint64_t val, orig;
if ((hyperv_features &
(CPUID_HV_MSR_TIME_REFCNT | CPUID_HV_MSR_REFERENCE_TSC)) !=
(CPUID_HV_MSR_TIME_REFCNT | CPUID_HV_MSR_REFERENCE_TSC) ||
(cpu_feature & CPUID_SSE2) == 0) /* SSE2 for mfence/lfence */
return;
switch (cpu_vendor_id) {
case CPU_VENDOR_AMD:
hyperv_tsc_timecounter.tc_get_timecount =
hyperv_tsc_timecount_mfence;
break;
case CPU_VENDOR_INTEL:
hyperv_tsc_timecounter.tc_get_timecount =
hyperv_tsc_timecount_lfence;
break;
default:
/* Unsupport CPU vendors. */
return;
}
hyperv_ref_tsc.tsc_ref = hyperv_dmamem_alloc(NULL, PAGE_SIZE, 0,
sizeof(struct hyperv_reftsc), &hyperv_ref_tsc.tsc_ref_dma,
BUS_DMA_WAITOK | BUS_DMA_ZERO);
if (hyperv_ref_tsc.tsc_ref == NULL) {
printf("hyperv: reftsc page allocation failed\n");
return;
}
orig = rdmsr(MSR_HV_REFERENCE_TSC);
val = MSR_HV_REFTSC_ENABLE | (orig & MSR_HV_REFTSC_RSVD_MASK) |
((hyperv_ref_tsc.tsc_ref_dma.hv_paddr >> PAGE_SHIFT) <<
MSR_HV_REFTSC_PGSHIFT);
wrmsr(MSR_HV_REFERENCE_TSC, val);
/* Register "enlightened" timecounter. */
tc_init(&hyperv_tsc_timecounter);
}
SYSINIT(hyperv_tsc_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, hyperv_tsc_tcinit,
NULL);

16
sys/dev/hyperv/vmbus/hyperv_reg.h
View File

@ -57,6 +57,11 @@
#define MSR_HV_VP_INDEX 0x40000002
#define MSR_HV_REFERENCE_TSC 0x40000021
#define MSR_HV_REFTSC_ENABLE 0x0001ULL
#define MSR_HV_REFTSC_RSVD_MASK 0x0ffeULL
#define MSR_HV_REFTSC_PGSHIFT 12
#define MSR_HV_SCONTROL 0x40000080
#define MSR_HV_SCTRL_ENABLE 0x0001ULL
#define MSR_HV_SCTRL_RSVD_MASK 0xfffffffffffffffeULL
@ -123,6 +128,17 @@
#define CPUID_LEAF_HV_LIMITS 0x40000005
#define CPUID_LEAF_HV_HWFEATURES 0x40000006
/*
* Hyper-V Reference TSC
*/
struct hyperv_reftsc {
volatile uint32_t tsc_seq;
volatile uint32_t tsc_rsvd1;
volatile uint64_t tsc_scale;
volatile int64_t tsc_ofs;
} __packed __aligned(PAGE_SIZE);
CTASSERT(sizeof(struct hyperv_reftsc) == PAGE_SIZE);
/*
* Hyper-V Monitor Notification Facility
*/