* [PATCH V2 1/2] clocksource/Hyper-v: Allocate Hyper-V tsc page statically
2019-08-14 12:32 [PATCH V2 0/2] clocksource/Hyper-V: Add Hyper-V specific sched clock lantianyu1986
@ 2019-08-14 12:32 ` lantianyu1986
2019-08-16 15:00 ` Daniel Lezcano
2019-08-14 12:32 ` [PATCH V2 2/2] clocksource/Hyper-V: Add Hyper-V specific sched clock function lantianyu1986
1 sibling, 1 reply; 4+ messages in thread
From: lantianyu1986 @ 2019-08-14 12:32 UTC (permalink / raw)
To: luto, tglx, mingo, bp, hpa, x86, kys, haiyangz, sthemmin, sashal,
daniel.lezcano, arnd, michael.h.kelley
Cc: Tianyu Lan, linux-kernel, linux-hyperv, linux-arch
From: Tianyu Lan <Tianyu.Lan@microsoft.com>
Prepare to add Hyper-V sched clock callback and move Hyper-V
Reference TSC initialization much earlier in the boot process. Earlier
initialization is needed so that it happens while the timestamp value
is still 0 and no discontinuity in the timestamp will occur when
pv_ops.time.sched_clock calculates its offset. The earlier
initialization requires that the Hyper-V TSC page be allocated
statically instead of with vmalloc(), so fixup the references
to the TSC page and the method of getting its physical address.
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
Change since v1:
- Update commit log
- Remove and operation of tsc page's va with PAGE_MASK
arch/x86/entry/vdso/vma.c | 2 +-
drivers/clocksource/hyperv_timer.c | 12 ++++--------
2 files changed, 5 insertions(+), 9 deletions(-)
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 349a61d8bf34..f5937742b290 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -122,7 +122,7 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
if (tsc_pg && vclock_was_used(VCLOCK_HVCLOCK))
return vmf_insert_pfn(vma, vmf->address,
- vmalloc_to_pfn(tsc_pg));
+ virt_to_phys(tsc_pg) >> PAGE_SHIFT);
}
return VM_FAULT_SIGBUS;
diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index ba2c79e6a0ee..432aa331df04 100644
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c
@@ -214,17 +214,17 @@ EXPORT_SYMBOL_GPL(hyperv_cs);
#ifdef CONFIG_HYPERV_TSCPAGE
-static struct ms_hyperv_tsc_page *tsc_pg;
+static struct ms_hyperv_tsc_page tsc_pg __aligned(PAGE_SIZE);
struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
{
- return tsc_pg;
+ 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);
+ u64 current_tick = hv_read_tsc_page(&tsc_pg);
if (current_tick == U64_MAX)
hv_get_time_ref_count(current_tick);
@@ -280,12 +280,8 @@ static bool __init hv_init_tsc_clocksource(void)
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));
+ phys_addr = virt_to_phys(&tsc_pg);
/*
* The Hyper-V TLFS specifies to preserve the value of reserved
--
2.14.5
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH V2 2/2] clocksource/Hyper-V: Add Hyper-V specific sched clock function
2019-08-14 12:32 [PATCH V2 0/2] clocksource/Hyper-V: Add Hyper-V specific sched clock lantianyu1986
2019-08-14 12:32 ` [PATCH V2 1/2] clocksource/Hyper-v: Allocate Hyper-V tsc page statically lantianyu1986
@ 2019-08-14 12:32 ` lantianyu1986
1 sibling, 0 replies; 4+ messages in thread
From: lantianyu1986 @ 2019-08-14 12:32 UTC (permalink / raw)
To: kys, haiyangz, sthemmin, sashal, tglx, mingo, bp, hpa, x86,
daniel.lezcano, arnd, michael.h.kelley
Cc: Tianyu Lan, linux-hyperv, linux-kernel, linux-arch
From: Tianyu Lan <Tianyu.Lan@microsoft.com>
Hyper-V guests use the default native_sched_clock() in pv_ops.time.sched_clock
on x86. But native_sched_clock() directly uses the raw TSC value, which
can be discontinuous in a Hyper-V VM. Add the generic hv_setup_sched_clock()
to set the sched clock function appropriately. On x86, this sets pv_ops.time.
sched_clock to read the Hyper-V reference TSC value that is scaled and adjusted
to be continuous.
Also move the Hyper-V reference TSC initialization much earlier in the boot
process so no discontinuity is observed when pv_ops.time.sched_clock
calculates its offset.
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
arch/x86/hyperv/hv_init.c | 2 --
arch/x86/kernel/cpu/mshyperv.c | 8 ++++++++
drivers/clocksource/hyperv_timer.c | 22 ++++++++++++----------
include/asm-generic/mshyperv.h | 1 +
4 files changed, 21 insertions(+), 12 deletions(-)
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 0d258688c8cf..866dfb3dca48 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -301,8 +301,6 @@ void __init hyperv_init(void)
x86_init.pci.arch_init = hv_pci_init;
- /* Register Hyper-V specific clocksource */
- hv_init_clocksource();
return;
remove_cpuhp_state:
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 062f77279ce3..53afd33990eb 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -29,6 +29,7 @@
#include <asm/timer.h>
#include <asm/reboot.h>
#include <asm/nmi.h>
+#include <clocksource/hyperv_timer.h>
struct ms_hyperv_info ms_hyperv;
EXPORT_SYMBOL_GPL(ms_hyperv);
@@ -338,9 +339,16 @@ static void __init ms_hyperv_init_platform(void)
x2apic_phys = 1;
# endif
+ /* Register Hyper-V specific clocksource */
+ hv_init_clocksource();
#endif
}
+void hv_setup_sched_clock(void *sched_clock)
+{
+ pv_ops.time.sched_clock = sched_clock;
+}
+
const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
.name = "Microsoft Hyper-V",
.detect = ms_hyperv_platform,
diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index 432aa331df04..dad8af198e20 100644
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c
@@ -215,6 +215,7 @@ EXPORT_SYMBOL_GPL(hyperv_cs);
#ifdef CONFIG_HYPERV_TSCPAGE
static struct ms_hyperv_tsc_page tsc_pg __aligned(PAGE_SIZE);
+static u64 hv_sched_clock_offset __ro_after_init;
struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
{
@@ -222,7 +223,7 @@ struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
}
EXPORT_SYMBOL_GPL(hv_get_tsc_page);
-static u64 notrace read_hv_sched_clock_tsc(void)
+static u64 notrace read_hv_clock_tsc(struct clocksource *arg)
{
u64 current_tick = hv_read_tsc_page(&tsc_pg);
@@ -232,9 +233,9 @@ static u64 notrace read_hv_sched_clock_tsc(void)
return current_tick;
}
-static u64 read_hv_clock_tsc(struct clocksource *arg)
+static u64 read_hv_sched_clock_tsc(void)
{
- return read_hv_sched_clock_tsc();
+ return read_hv_clock_tsc(NULL) - hv_sched_clock_offset;
}
static struct clocksource hyperv_cs_tsc = {
@@ -246,7 +247,7 @@ static struct clocksource hyperv_cs_tsc = {
};
#endif
-static u64 notrace read_hv_sched_clock_msr(void)
+static u64 notrace read_hv_clock_msr(struct clocksource *arg)
{
u64 current_tick;
/*
@@ -258,9 +259,9 @@ static u64 notrace read_hv_sched_clock_msr(void)
return current_tick;
}
-static u64 read_hv_clock_msr(struct clocksource *arg)
+static u64 read_hv_sched_clock_msr(void)
{
- return read_hv_sched_clock_msr();
+ return read_hv_clock_msr(NULL) - hv_sched_clock_offset;
}
static struct clocksource hyperv_cs_msr = {
@@ -298,8 +299,9 @@ static bool __init hv_init_tsc_clocksource(void)
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);
+ hv_sched_clock_offset = hyperv_cs->read(hyperv_cs);
+ hv_setup_sched_clock(read_hv_sched_clock_tsc);
+
return true;
}
#else
@@ -329,7 +331,7 @@ void __init hv_init_clocksource(void)
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);
+ hv_sched_clock_offset = hyperv_cs->read(hyperv_cs);
+ hv_setup_sched_clock(read_hv_sched_clock_msr);
}
EXPORT_SYMBOL_GPL(hv_init_clocksource);
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index 0becb7d9704d..18d8e2d8210f 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -167,6 +167,7 @@ void hyperv_report_panic(struct pt_regs *regs, long err);
void hyperv_report_panic_msg(phys_addr_t pa, size_t size);
bool hv_is_hyperv_initialized(void);
void hyperv_cleanup(void);
+void hv_setup_sched_clock(void *sched_clock);
#else /* CONFIG_HYPERV */
static inline bool hv_is_hyperv_initialized(void) { return false; }
static inline void hyperv_cleanup(void) {}
--
2.14.5
^ permalink raw reply related [flat|nested] 4+ messages in thread