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clocksource/drivers: Continue making Hyper-V clocksource ISA agnostic 

Continue consolidating Hyper-V clock and timer code into an ISA
independent Hyper-V clocksource driver.

Move the existing clocksource code under drivers/hv and arch/x86 to the new
clocksource driver while separating out the ISA dependencies. Update
Hyper-V initialization to call initialization and cleanup routines since
the Hyper-V synthetic clock is not independently enumerated in ACPI.

Update Hyper-V clocksource users in KVM and VDSO to get definitions from
the new include file.

No behavior is changed and no new functionality is added.

Suggested-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: "bp@alien8.de" <bp@alien8.de>
Cc: "will.deacon@arm.com" <will.deacon@arm.com>
Cc: "catalin.marinas@arm.com" <catalin.marinas@arm.com>
Cc: "mark.rutland@arm.com" <mark.rutland@arm.com>
Cc: "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>
Cc: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
Cc: "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>
Cc: "olaf@aepfle.de" <olaf@aepfle.de>
Cc: "apw@canonical.com" <apw@canonical.com>
Cc: "jasowang@redhat.com" <jasowang@redhat.com>
Cc: "marcelo.cerri@canonical.com" <marcelo.cerri@canonical.com>
Cc: Sunil Muthuswamy <sunilmut@microsoft.com>
Cc: KY Srinivasan <kys@microsoft.com>
Cc: "sashal@kernel.org" <sashal@kernel.org>
Cc: "vincenzo.frascino@arm.com" <vincenzo.frascino@arm.com>
Cc: "linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>
Cc: "linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org>
Cc: "linux-kselftest@vger.kernel.org" <linux-kselftest@vger.kernel.org>
Cc: "arnd@arndb.de" <arnd@arndb.de>
Cc: "linux@armlinux.org.uk" <linux@armlinux.org.uk>
Cc: "ralf@linux-mips.org" <ralf@linux-mips.org>
Cc: "paul.burton@mips.com" <paul.burton@mips.com>
Cc: "daniel.lezcano@linaro.org" <daniel.lezcano@linaro.org>
Cc: "salyzyn@android.com" <salyzyn@android.com>
Cc: "pcc@google.com" <pcc@google.com>
Cc: "shuah@kernel.org" <shuah@kernel.org>
Cc: "0x7f454c46@gmail.com" <0x7f454c46@gmail.com>
Cc: "linux@rasmusvillemoes.dk" <linux@rasmusvillemoes.dk>
Cc: "huw@codeweavers.com" <huw@codeweavers.com>
Cc: "sfr@canb.auug.org.au" <sfr@canb.auug.org.au>
Cc: "pbonzini@redhat.com" <pbonzini@redhat.com>
Cc: "rkrcmar@redhat.com" <rkrcmar@redhat.com>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>
Link: https://lkml.kernel.org/r/1561955054-1838-3-git-send-email-mikelley@microsoft.com
This commit is contained in:
Michael Kelley 2019-07-01 04:26:06 +00:00 committed by Thomas Gleixner
parent fd1fea6834
commit dd2cb34861
8 changed files with 237 additions and 160 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/entry/vdso/vma.c
View File

@ -22,7 +22,7 @@
#include <asm/page.h>
#include <asm/desc.h>
#include <asm/cpufeature.h>
#include <asm/mshyperv.h>
#include <clocksource/hyperv_timer.h>
#if defined(CONFIG_X86_64)
unsigned int __read_mostly vdso64_enabled = 1;

91
arch/x86/hyperv/hv_init.c
View File

@ -17,64 +17,13 @@
#include <linux/version.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/clockchips.h>
#include <linux/hyperv.h>
#include <linux/slab.h>
#include <linux/cpuhotplug.h>
#ifdef CONFIG_HYPERV_TSCPAGE
static struct ms_hyperv_tsc_page *tsc_pg;
struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
{
return tsc_pg;
}
EXPORT_SYMBOL_GPL(hv_get_tsc_page);
static u64 read_hv_clock_tsc(struct clocksource *arg)
{
u64 current_tick = hv_read_tsc_page(tsc_pg);
if (current_tick == U64_MAX)
rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
return current_tick;
}
static struct clocksource hyperv_cs_tsc = {
.name = "hyperv_clocksource_tsc_page",
.rating = 400,
.read = read_hv_clock_tsc,
.mask = CLOCKSOURCE_MASK(64),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
#endif
static u64 read_hv_clock_msr(struct clocksource *arg)
{
u64 current_tick;
/*
* Read the partition counter to get the current tick count. This count
* is set to 0 when the partition is created and is incremented in
* 100 nanosecond units.
*/
rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
return current_tick;
}
static struct clocksource hyperv_cs_msr = {
.name = "hyperv_clocksource_msr",
.rating = 400,
.read = read_hv_clock_msr,
.mask = CLOCKSOURCE_MASK(64),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
#include <clocksource/hyperv_timer.h>
void *hv_hypercall_pg;
EXPORT_SYMBOL_GPL(hv_hypercall_pg);
struct clocksource *hyperv_cs;
EXPORT_SYMBOL_GPL(hyperv_cs);
u32 *hv_vp_index;
EXPORT_SYMBOL_GPL(hv_vp_index);
@ -343,42 +292,8 @@ void __init hyperv_init(void)
x86_init.pci.arch_init = hv_pci_init;
/*
* Register Hyper-V specific clocksource.
*/
#ifdef CONFIG_HYPERV_TSCPAGE
if (ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE) {
union hv_x64_msr_hypercall_contents tsc_msr;
tsc_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
if (!tsc_pg)
goto register_msr_cs;
hyperv_cs = &hyperv_cs_tsc;
rdmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
tsc_msr.enable = 1;
tsc_msr.guest_physical_address = vmalloc_to_pfn(tsc_pg);
wrmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
hyperv_cs_tsc.archdata.vclock_mode = VCLOCK_HVCLOCK;
clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);
return;
}
register_msr_cs:
#endif
/*
* For 32 bit guests just use the MSR based mechanism for reading
* the partition counter.
*/
hyperv_cs = &hyperv_cs_msr;
if (ms_hyperv.features & HV_MSR_TIME_REF_COUNT_AVAILABLE)
clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);
/* Register Hyper-V specific clocksource */
hv_init_clocksource();
return;
remove_cpuhp_state:

81
arch/x86/include/asm/mshyperv.h
View File

@ -105,6 +105,17 @@ static inline void vmbus_signal_eom(struct hv_message *msg, u32 old_msg_type)
#define hv_get_crash_ctl(val) \
rdmsrl(HV_X64_MSR_CRASH_CTL, val)
#define hv_get_time_ref_count(val) \
rdmsrl(HV_X64_MSR_TIME_REF_COUNT, val)
#define hv_get_reference_tsc(val) \
rdmsrl(HV_X64_MSR_REFERENCE_TSC, val)
#define hv_set_reference_tsc(val) \
wrmsrl(HV_X64_MSR_REFERENCE_TSC, val)
#define hv_set_clocksource_vdso(val) \
((val).archdata.vclock_mode = VCLOCK_HVCLOCK)
#define hv_get_raw_timer() rdtsc_ordered()
void hyperv_callback_vector(void);
void hyperv_reenlightenment_vector(void);
#ifdef CONFIG_TRACING
@ -133,7 +144,6 @@ static inline void hv_disable_stimer0_percpu_irq(int irq) {}
#if IS_ENABLED(CONFIG_HYPERV)
extern struct clocksource *hyperv_cs;
extern void *hv_hypercall_pg;
extern void __percpu **hyperv_pcpu_input_arg;
@ -387,73 +397,4 @@ static inline int hyperv_flush_guest_mapping_range(u64 as,
}
#endif /* CONFIG_HYPERV */
#ifdef CONFIG_HYPERV_TSCPAGE
struct ms_hyperv_tsc_page *hv_get_tsc_page(void);
static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg,
u64 *cur_tsc)
{
u64 scale, offset;
u32 sequence;
/*
* The protocol for reading Hyper-V TSC page is specified in Hypervisor
* Top-Level Functional Specification ver. 3.0 and above. To get the
* reference time we must do the following:
* - READ ReferenceTscSequence
* A special '0' value indicates the time source is unreliable and we
* need to use something else. The currently published specification
* versions (up to 4.0b) contain a mistake and wrongly claim '-1'
* instead of '0' as the special value, see commit c35b82ef0294.
* - ReferenceTime =
* ((RDTSC() * ReferenceTscScale) >> 64) + ReferenceTscOffset
* - READ ReferenceTscSequence again. In case its value has changed
* since our first reading we need to discard ReferenceTime and repeat
* the whole sequence as the hypervisor was updating the page in
* between.
*/
do {
sequence = READ_ONCE(tsc_pg->tsc_sequence);
if (!sequence)
return U64_MAX;
/*
* Make sure we read sequence before we read other values from
* TSC page.
*/
smp_rmb();
scale = READ_ONCE(tsc_pg->tsc_scale);
offset = READ_ONCE(tsc_pg->tsc_offset);
*cur_tsc = rdtsc_ordered();
/*
* Make sure we read sequence after we read all other values
* from TSC page.
*/
smp_rmb();
} while (READ_ONCE(tsc_pg->tsc_sequence) != sequence);
return mul_u64_u64_shr(*cur_tsc, scale, 64) + offset;
}
static inline u64 hv_read_tsc_page(const struct ms_hyperv_tsc_page *tsc_pg)
{
u64 cur_tsc;
return hv_read_tsc_page_tsc(tsc_pg, &cur_tsc);
}
#else
static inline struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
{
return NULL;
}
static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg,
u64 *cur_tsc)
{
BUG();
return U64_MAX;
}
#endif
#endif

2
arch/x86/include/asm/vdso/gettimeofday.h
View File

@ -18,7 +18,7 @@
#include <asm/unistd.h>
#include <asm/msr.h>
#include <asm/pvclock.h>
#include <asm/mshyperv.h>
#include <clocksource/hyperv_timer.h>
#define __vdso_data (VVAR(_vdso_data))

1
arch/x86/kvm/x86.c
View File

@ -67,6 +67,7 @@
#include <asm/mshyperv.h>
#include <asm/hypervisor.h>
#include <asm/intel_pt.h>
#include <clocksource/hyperv_timer.h>
#define CREATE_TRACE_POINTS
#include "trace.h"

139
drivers/clocksource/hyperv_timer.c
View File

@ -14,6 +14,8 @@
#include <linux/percpu.h>
#include <linux/cpumask.h>
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/sched_clock.h>
#include <linux/mm.h>
#include <clocksource/hyperv_timer.h>
#include <asm/hyperv-tlfs.h>
@ -198,3 +200,140 @@ void hv_stimer_global_cleanup(void)
hv_stimer_free();
}
EXPORT_SYMBOL_GPL(hv_stimer_global_cleanup);
/*
* Code and definitions for the Hyper-V clocksources. Two
* clocksources are defined: one that reads the Hyper-V defined MSR, and
* the other that uses the TSC reference page feature as defined in the
* TLFS. The MSR version is for compatibility with old versions of
* Hyper-V and 32-bit x86. The TSC reference page version is preferred.
*/
struct clocksource *hyperv_cs;
EXPORT_SYMBOL_GPL(hyperv_cs);
#ifdef CONFIG_HYPERV_TSCPAGE
static struct ms_hyperv_tsc_page *tsc_pg;
struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
{
return tsc_pg;
}
EXPORT_SYMBOL_GPL(hv_get_tsc_page);
static u64 notrace read_hv_sched_clock_tsc(void)
{
u64 current_tick = hv_read_tsc_page(tsc_pg);
if (current_tick == U64_MAX)
hv_get_time_ref_count(current_tick);
return current_tick;
}
static u64 read_hv_clock_tsc(struct clocksource *arg)
{
return read_hv_sched_clock_tsc();
}
static struct clocksource hyperv_cs_tsc = {
.name = "hyperv_clocksource_tsc_page",
.rating = 400,
.read = read_hv_clock_tsc,
.mask = CLOCKSOURCE_MASK(64),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
#endif
static u64 notrace read_hv_sched_clock_msr(void)
{
u64 current_tick;
/*
* Read the partition counter to get the current tick count. This count
* is set to 0 when the partition is created and is incremented in
* 100 nanosecond units.
*/
hv_get_time_ref_count(current_tick);
return current_tick;
}
static u64 read_hv_clock_msr(struct clocksource *arg)
{
return read_hv_sched_clock_msr();
}
static struct clocksource hyperv_cs_msr = {
.name = "hyperv_clocksource_msr",
.rating = 400,
.read = read_hv_clock_msr,
.mask = CLOCKSOURCE_MASK(64),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
#ifdef CONFIG_HYPERV_TSCPAGE
static bool __init hv_init_tsc_clocksource(void)
{
u64 tsc_msr;
phys_addr_t phys_addr;
if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE))
return false;
tsc_pg = vmalloc(PAGE_SIZE);
if (!tsc_pg)
return false;
hyperv_cs = &hyperv_cs_tsc;
phys_addr = page_to_phys(vmalloc_to_page(tsc_pg));
/*
* The Hyper-V TLFS specifies to preserve the value of reserved
* bits in registers. So read the existing value, preserve the
* low order 12 bits, and add in the guest physical address
* (which already has at least the low 12 bits set to zero since
* it is page aligned). Also set the "enable" bit, which is bit 0.
*/
hv_get_reference_tsc(tsc_msr);
tsc_msr &= GENMASK_ULL(11, 0);
tsc_msr = tsc_msr | 0x1 | (u64)phys_addr;
hv_set_reference_tsc(tsc_msr);
hv_set_clocksource_vdso(hyperv_cs_tsc);
clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);
/* sched_clock_register is needed on ARM64 but is a no-op on x86 */
sched_clock_register(read_hv_sched_clock_tsc, 64, HV_CLOCK_HZ);
return true;
}
#else
static bool __init hv_init_tsc_clocksource(void)
{
return false;
}
#endif
void __init hv_init_clocksource(void)
{
/*
* Try to set up the TSC page clocksource. If it succeeds, we're
* done. Otherwise, set up the MSR clocksoruce. At least one of
* these will always be available except on very old versions of
* Hyper-V on x86. In that case we won't have a Hyper-V
* clocksource, but Linux will still run with a clocksource based
* on the emulated PIT or LAPIC timer.
*/
if (hv_init_tsc_clocksource())
return;
if (!(ms_hyperv.features & HV_MSR_TIME_REF_COUNT_AVAILABLE))
return;
hyperv_cs = &hyperv_cs_msr;
clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);
/* sched_clock_register is needed on ARM64 but is a no-op on x86 */
sched_clock_register(read_hv_sched_clock_msr, 64, HV_CLOCK_HZ);
}
EXPORT_SYMBOL_GPL(hv_init_clocksource);

1
drivers/hv/hv_util.c
View File

@ -17,6 +17,7 @@
#include <linux/hyperv.h>
#include <linux/clockchips.h>
#include <linux/ptp_clock_kernel.h>
#include <clocksource/hyperv_timer.h>
#include <asm/mshyperv.h>
#include "hyperv_vmbus.h"

80
include/clocksource/hyperv_timer.h
View File

@ -13,6 +13,10 @@
#ifndef __CLKSOURCE_HYPERV_TIMER_H
#define __CLKSOURCE_HYPERV_TIMER_H
#include <linux/clocksource.h>
#include <linux/math64.h>
#include <asm/mshyperv.h>
#define HV_MAX_MAX_DELTA_TICKS 0xffffffff
#define HV_MIN_DELTA_TICKS 1
@ -24,4 +28,80 @@ extern void hv_stimer_cleanup(unsigned int cpu);
extern void hv_stimer_global_cleanup(void);
extern void hv_stimer0_isr(void);
#if IS_ENABLED(CONFIG_HYPERV)
extern struct clocksource *hyperv_cs;
extern void hv_init_clocksource(void);
#endif /* CONFIG_HYPERV */
#ifdef CONFIG_HYPERV_TSCPAGE
extern struct ms_hyperv_tsc_page *hv_get_tsc_page(void);
static inline notrace u64
hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, u64 *cur_tsc)
{
u64 scale, offset;
u32 sequence;
/*
* The protocol for reading Hyper-V TSC page is specified in Hypervisor
* Top-Level Functional Specification ver. 3.0 and above. To get the
* reference time we must do the following:
* - READ ReferenceTscSequence
* A special '0' value indicates the time source is unreliable and we
* need to use something else. The currently published specification
* versions (up to 4.0b) contain a mistake and wrongly claim '-1'
* instead of '0' as the special value, see commit c35b82ef0294.
* - ReferenceTime =
* ((RDTSC() * ReferenceTscScale) >> 64) + ReferenceTscOffset
* - READ ReferenceTscSequence again. In case its value has changed
* since our first reading we need to discard ReferenceTime and repeat
* the whole sequence as the hypervisor was updating the page in
* between.
*/
do {
sequence = READ_ONCE(tsc_pg->tsc_sequence);
if (!sequence)
return U64_MAX;
/*
* Make sure we read sequence before we read other values from
* TSC page.
*/
smp_rmb();
scale = READ_ONCE(tsc_pg->tsc_scale);
offset = READ_ONCE(tsc_pg->tsc_offset);
*cur_tsc = hv_get_raw_timer();
/*
* Make sure we read sequence after we read all other values
* from TSC page.
*/
smp_rmb();
} while (READ_ONCE(tsc_pg->tsc_sequence) != sequence);
return mul_u64_u64_shr(*cur_tsc, scale, 64) + offset;
}
static inline notrace u64
hv_read_tsc_page(const struct ms_hyperv_tsc_page *tsc_pg)
{
u64 cur_tsc;
return hv_read_tsc_page_tsc(tsc_pg, &cur_tsc);
}
#else /* CONFIG_HYPERV_TSC_PAGE */
static inline struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
{
return NULL;
}
static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg,
u64 *cur_tsc)
{
return U64_MAX;
}
#endif /* CONFIG_HYPERV_TSCPAGE */
#endif