* [PATCH v3 0/2] Drivers: hv: Move Hyper-V clock/timer code to separate clocksource driver
@ 2019-05-27 14:59 Michael Kelley
2019-05-27 14:59 ` [PATCH v3 1/2] Drivers: hv: Create Hyper-V clocksource driver from existing clockevents code Michael Kelley
` (2 more replies)
0 siblings, 3 replies; 8+ messages in thread
From: Michael Kelley @ 2019-05-27 14:59 UTC (permalink / raw)
To: will.deacon, marc.zyngier, linux-arm-kernel, gregkh,
linux-kernel, linux-hyperv, olaf, apw, vkuznets, jasowang,
marcelo.cerri, Sunil Muthuswamy, KY Srinivasan
Cc: Michael Kelley, catalin.marinas, mark.rutland
This patch series moves Hyper-V clock/timer code to a separate Hyper-V
clocksource driver. Previously, Hyper-V clock/timer code and data
structures were mixed in with other Hyper-V code in the ISA independent
drivers/hv code as well as in arch dependent code. The new Hyper-V
clocksource driver is ISA independent, with a just few dependencies on
arch specific functions. The patch series does not change any behavior
or functionality -- it only reorganizes the existing code and fixes up
the linkages. A few places outside of Hyper-V code are fixed up to use
the new #include file structure.
This restructuring is in response to Marc Zyngier's review comments
on supporting Hyper-V running on ARM64, and is a good idea in general.
It increases the amount of code shared between the x86 and ARM64
architectures, and reduces the size of the new code for supporting
Hyper-V on ARM64. A new version of the Hyper-V on ARM64 patches will
follow once this clocksource restructuring is accepted.
The code is diff'ed against Linux 5.2.0-rc1-next-20190524.
Changes in v3:
* Removed boolean argument to hv_init_clocksource(). Always call
sched_clock_register, which is needed on ARM64 but a no-op on x86.
* Removed separate cpuhp setup in hv_stimer_alloc() and instead
directly call hv_stimer_init() and hv_stimer_cleanup() from
corresponding VMbus functions. This more closely matches original
code and avoids clocksource stop/restart problems on ARM64 when
VMbus code denies CPU offlining request.
Changes in v2:
* Revised commit short descriptions so the distinction between
the first and second patches is clearer [GregKH]
* Renamed new clocksource driver files and functions to use
existing "timer" and "stimer" names instead of introducing
"syntimer". [Vitaly Kuznetsov]
* Introduced CONFIG_HYPER_TIMER to fix build problem when
CONFIG_HYPERV=m [Vitaly Kuznetsov]
* Added "Suggested-by: Marc Zyngier"
Michael Kelley (2):
Drivers: hv: Create Hyper-V clocksource driver from existing
clockevents code
Drivers: hv: Move Hyper-V clocksource code to new clocksource driver
MAINTAINERS | 2 +
arch/x86/entry/vdso/vclock_gettime.c | 1 +
arch/x86/entry/vdso/vma.c | 2 +-
arch/x86/hyperv/hv_init.c | 91 +---------
arch/x86/include/asm/hyperv-tlfs.h | 6 +
arch/x86/include/asm/mshyperv.h | 81 ++-------
arch/x86/kernel/cpu/mshyperv.c | 2 +
arch/x86/kvm/x86.c | 1 +
drivers/clocksource/Makefile | 1 +
drivers/clocksource/hyperv_timer.c | 321 +++++++++++++++++++++++++++++++++++
drivers/hv/Kconfig | 3 +
drivers/hv/hv.c | 156 +----------------
drivers/hv/hv_util.c | 1 +
drivers/hv/hyperv_vmbus.h | 3 -
drivers/hv/vmbus_drv.c | 42 ++---
include/clocksource/hyperv_timer.h | 105 ++++++++++++
16 files changed, 484 insertions(+), 334 deletions(-)
create mode 100644 drivers/clocksource/hyperv_timer.c
create mode 100644 include/clocksource/hyperv_timer.h
--
1.8.3.1
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH v3 1/2] Drivers: hv: Create Hyper-V clocksource driver from existing clockevents code
2019-05-27 14:59 [PATCH v3 0/2] Drivers: hv: Move Hyper-V clock/timer code to separate clocksource driver Michael Kelley
@ 2019-05-27 14:59 ` Michael Kelley
2019-05-30 9:37 ` Vitaly Kuznetsov
2019-05-27 14:59 ` [PATCH v3 2/2] Drivers: hv: Move Hyper-V clocksource code to new clocksource driver Michael Kelley
2019-06-06 16:37 ` [PATCH v3 0/2] Drivers: hv: Move Hyper-V clock/timer code to separate " Sasha Levin
2 siblings, 1 reply; 8+ messages in thread
From: Michael Kelley @ 2019-05-27 14:59 UTC (permalink / raw)
To: will.deacon, marc.zyngier, linux-arm-kernel, gregkh,
linux-kernel, linux-hyperv, olaf, apw, vkuznets, jasowang,
marcelo.cerri, Sunil Muthuswamy, KY Srinivasan
Cc: Michael Kelley, catalin.marinas, mark.rutland
Clockevents code for Hyper-V synthetic timers is currently mixed
in with other Hyper-V code. Move the code to a Hyper-V specific
driver in the "clocksource" directory. Update the VMbus driver
to call initialization and cleanup routines since the Hyper-V
synthetic timers are not independently enumerated in ACPI.
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>
---
MAINTAINERS | 2 +
arch/x86/include/asm/hyperv-tlfs.h | 6 ++
arch/x86/kernel/cpu/mshyperv.c | 2 +
drivers/clocksource/Makefile | 1 +
drivers/clocksource/hyperv_timer.c | 191 +++++++++++++++++++++++++++++++++++++
drivers/hv/Kconfig | 3 +
drivers/hv/hv.c | 156 +-----------------------------
drivers/hv/hyperv_vmbus.h | 3 -
drivers/hv/vmbus_drv.c | 42 ++++----
include/clocksource/hyperv_timer.h | 27 ++++++
10 files changed, 258 insertions(+), 175 deletions(-)
create mode 100644 drivers/clocksource/hyperv_timer.c
create mode 100644 include/clocksource/hyperv_timer.h
diff --git a/MAINTAINERS b/MAINTAINERS
index 992f1dd..cf2a5b7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7294,6 +7294,7 @@ F: arch/x86/include/asm/trace/hyperv.h
F: arch/x86/include/asm/hyperv-tlfs.h
F: arch/x86/kernel/cpu/mshyperv.c
F: arch/x86/hyperv
+F: drivers/clocksource/hyperv_timer.c
F: drivers/hid/hid-hyperv.c
F: drivers/hv/
F: drivers/input/serio/hyperv-keyboard.c
@@ -7304,6 +7305,7 @@ F: drivers/uio/uio_hv_generic.c
F: drivers/video/fbdev/hyperv_fb.c
F: drivers/iommu/hyperv_iommu.c
F: net/vmw_vsock/hyperv_transport.c
+F: include/clocksource/hyperv_timer.h
F: include/linux/hyperv.h
F: include/uapi/linux/hyperv.h
F: tools/hv/
diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
index cdf44aa..af78cd7 100644
--- a/arch/x86/include/asm/hyperv-tlfs.h
+++ b/arch/x86/include/asm/hyperv-tlfs.h
@@ -401,6 +401,12 @@ enum HV_GENERIC_SET_FORMAT {
#define HV_STATUS_INVALID_CONNECTION_ID 18
#define HV_STATUS_INSUFFICIENT_BUFFERS 19
+/*
+ * The Hyper-V TimeRefCount register and the TSC
+ * page provide a guest VM clock with 100ns tick rate
+ */
+#define HV_CLOCK_HZ (NSEC_PER_SEC/100)
+
typedef struct _HV_REFERENCE_TSC_PAGE {
__u32 tsc_sequence;
__u32 res1;
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index faae611..b18ede4 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -21,6 +21,7 @@
#include <linux/irq.h>
#include <linux/kexec.h>
#include <linux/i8253.h>
+#include <linux/random.h>
#include <asm/processor.h>
#include <asm/hypervisor.h>
#include <asm/hyperv-tlfs.h>
@@ -84,6 +85,7 @@ __visible void __irq_entry hv_stimer0_vector_handler(struct pt_regs *regs)
inc_irq_stat(hyperv_stimer0_count);
if (hv_stimer0_handler)
hv_stimer0_handler();
+ add_interrupt_randomness(HYPERV_STIMER0_VECTOR, 0);
ack_APIC_irq();
exiting_irq();
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 236858f..2b65c5f 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -84,3 +84,4 @@ obj-$(CONFIG_ATCPIT100_TIMER) += timer-atcpit100.o
obj-$(CONFIG_RISCV_TIMER) += timer-riscv.o
obj-$(CONFIG_CSKY_MP_TIMER) += timer-mp-csky.o
obj-$(CONFIG_GX6605S_TIMER) += timer-gx6605s.o
+obj-$(CONFIG_HYPERV_TIMER) += hyperv_timer.o
diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
new file mode 100644
index 0000000..30615f3
--- /dev/null
+++ b/drivers/clocksource/hyperv_timer.c
@@ -0,0 +1,191 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Clocksource driver for the synthetic counter and timers
+ * provided by the Hyper-V hypervisor to guest VMs, as described
+ * in the Hyper-V Top Level Functional Spec (TLFS). This driver
+ * is instruction set architecture independent.
+ *
+ * Copyright (C) 2019, Microsoft, Inc.
+ *
+ * Author: Michael Kelley <mikelley@microsoft.com>
+ */
+
+#include <linux/percpu.h>
+#include <linux/cpumask.h>
+#include <linux/clockchips.h>
+#include <linux/mm.h>
+#include <clocksource/hyperv_timer.h>
+#include <asm/hyperv-tlfs.h>
+#include <asm/mshyperv.h>
+
+static struct clock_event_device __percpu *hv_clock_event;
+
+/*
+ * If false, we're using the old mechanism for stimer0 interrupts
+ * where it sends a VMbus message when it expires. The old
+ * mechanism is used when running on older versions of Hyper-V
+ * that don't support Direct Mode. While Hyper-V provides
+ * four stimer's per CPU, Linux uses only stimer0.
+ */
+static bool direct_mode_enabled;
+
+static int stimer0_irq;
+static int stimer0_vector;
+static int stimer0_message_sint;
+
+/*
+ * ISR for when stimer0 is operating in Direct Mode. Direct Mode
+ * does not use VMbus or any VMbus messages, so process here and not
+ * in the VMbus driver code.
+ */
+void hv_stimer0_isr(void)
+{
+ struct clock_event_device *ce;
+
+ ce = this_cpu_ptr(hv_clock_event);
+ ce->event_handler(ce);
+}
+EXPORT_SYMBOL_GPL(hv_stimer0_isr);
+
+static int hv_ce_set_next_event(unsigned long delta,
+ struct clock_event_device *evt)
+{
+ u64 current_tick;
+
+ WARN_ON(!clockevent_state_oneshot(evt));
+
+ current_tick = hyperv_cs->read(NULL);
+ current_tick += delta;
+ hv_init_timer(0, current_tick);
+ return 0;
+}
+
+static int hv_ce_shutdown(struct clock_event_device *evt)
+{
+ hv_init_timer(0, 0);
+ hv_init_timer_config(0, 0);
+ if (direct_mode_enabled)
+ hv_disable_stimer0_percpu_irq(stimer0_irq);
+
+ return 0;
+}
+
+static int hv_ce_set_oneshot(struct clock_event_device *evt)
+{
+ union hv_stimer_config timer_cfg;
+
+ timer_cfg.as_uint64 = 0;
+ timer_cfg.enable = 1;
+ timer_cfg.auto_enable = 1;
+ if (direct_mode_enabled) {
+ /*
+ * When it expires, the timer will directly interrupt
+ * on the specified hardware vector/IRQ.
+ */
+ timer_cfg.direct_mode = 1;
+ timer_cfg.apic_vector = stimer0_vector;
+ hv_enable_stimer0_percpu_irq(stimer0_irq);
+ } else {
+ /*
+ * When it expires, the timer will generate a VMbus message,
+ * to be handled by the normal VMbus interrupt handler.
+ */
+ timer_cfg.direct_mode = 0;
+ timer_cfg.sintx = stimer0_message_sint;
+ }
+ hv_init_timer_config(0, timer_cfg.as_uint64);
+ return 0;
+}
+
+/*
+ * hv_stimer_init - Per-cpu initialization of the clockevent
+ */
+int hv_stimer_init(unsigned int cpu)
+{
+ struct clock_event_device *ce;
+
+ if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE) {
+ ce = per_cpu_ptr(hv_clock_event, cpu);
+ ce->name = "Hyper-V clockevent";
+ ce->features = CLOCK_EVT_FEAT_ONESHOT;
+ ce->cpumask = cpumask_of(cpu);
+ ce->rating = 1000;
+ ce->set_state_shutdown = hv_ce_shutdown;
+ ce->set_state_oneshot = hv_ce_set_oneshot;
+ ce->set_next_event = hv_ce_set_next_event;
+
+ clockevents_config_and_register(ce,
+ HV_CLOCK_HZ,
+ HV_MIN_DELTA_TICKS,
+ HV_MAX_MAX_DELTA_TICKS);
+ }
+ return 0;
+}
+EXPORT_SYMBOL_GPL(hv_stimer_init);
+
+/*
+ * hv_stimer_cleanup - Per-cpu cleanup of the clockevent
+ */
+int hv_stimer_cleanup(unsigned int cpu)
+{
+ struct clock_event_device *ce;
+
+ /* Turn off clockevent device */
+ if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE) {
+ ce = per_cpu_ptr(hv_clock_event, cpu);
+ clockevents_unbind_device(ce, cpu);
+ hv_ce_shutdown(ce);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(hv_stimer_cleanup);
+
+/* hv_stimer_alloc - Global initialization of the clockevent and stimer0 */
+int hv_stimer_alloc(int sint)
+{
+ hv_clock_event = alloc_percpu(struct clock_event_device);
+ if (!hv_clock_event)
+ return -ENOMEM;
+
+ direct_mode_enabled = ms_hyperv.misc_features &
+ HV_STIMER_DIRECT_MODE_AVAILABLE;
+ if (direct_mode_enabled &&
+ hv_setup_stimer0_irq(&stimer0_irq, &stimer0_vector,
+ hv_stimer0_isr)) {
+ free_percpu(hv_clock_event);
+ return -EINVAL;
+ }
+
+ stimer0_message_sint = sint;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(hv_stimer_alloc);
+
+/* hv_stimer_free - Free global resources allocated by hv_stimer_alloc() */
+void hv_stimer_free(void)
+{
+ if (direct_mode_enabled)
+ hv_remove_stimer0_irq(stimer0_irq);
+ free_percpu(hv_clock_event);
+}
+EXPORT_SYMBOL_GPL(hv_stimer_free);
+
+/*
+ * Do a global cleanup of clockevents for the cases of kexec and
+ * vmbus exit
+ */
+void hv_stimer_global_cleanup(void)
+{
+ int cpu;
+ struct clock_event_device *ce;
+
+ if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE)
+ for_each_present_cpu(cpu) {
+ ce = per_cpu_ptr(hv_clock_event, cpu);
+ clockevents_unbind_device(ce, cpu);
+ }
+ hv_stimer_free();
+}
+EXPORT_SYMBOL_GPL(hv_stimer_global_cleanup);
diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
index 1c1a251..c423e57 100644
--- a/drivers/hv/Kconfig
+++ b/drivers/hv/Kconfig
@@ -10,6 +10,9 @@ config HYPERV
Select this option to run Linux as a Hyper-V client operating
system.
+config HYPERV_TIMER
+ def_bool HYPERV
+
config HYPERV_TSCPAGE
def_bool HYPERV && X86_64
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 4565302..bd6452f 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -29,6 +29,7 @@
#include <linux/version.h>
#include <linux/random.h>
#include <linux/clockchips.h>
+#include <clocksource/hyperv_timer.h>
#include <asm/mshyperv.h>
#include "hyperv_vmbus.h"
@@ -36,21 +37,6 @@
struct hv_context hv_context;
/*
- * If false, we're using the old mechanism for stimer0 interrupts
- * where it sends a VMbus message when it expires. The old
- * mechanism is used when running on older versions of Hyper-V
- * that don't support Direct Mode. While Hyper-V provides
- * four stimer's per CPU, Linux uses only stimer0.
- */
-static bool direct_mode_enabled;
-static int stimer0_irq;
-static int stimer0_vector;
-
-#define HV_TIMER_FREQUENCY (10 * 1000 * 1000) /* 100ns period */
-#define HV_MAX_MAX_DELTA_TICKS 0xffffffff
-#define HV_MIN_DELTA_TICKS 1
-
-/*
* hv_init - Main initialization routine.
*
* This routine must be called before any other routines in here are called
@@ -60,9 +46,6 @@ int hv_init(void)
hv_context.cpu_context = alloc_percpu(struct hv_per_cpu_context);
if (!hv_context.cpu_context)
return -ENOMEM;
-
- direct_mode_enabled = ms_hyperv.misc_features &
- HV_STIMER_DIRECT_MODE_AVAILABLE;
return 0;
}
@@ -101,89 +84,6 @@ int hv_post_message(union hv_connection_id connection_id,
return status & 0xFFFF;
}
-/*
- * ISR for when stimer0 is operating in Direct Mode. Direct Mode
- * does not use VMbus or any VMbus messages, so process here and not
- * in the VMbus driver code.
- */
-
-static void hv_stimer0_isr(void)
-{
- struct hv_per_cpu_context *hv_cpu;
-
- hv_cpu = this_cpu_ptr(hv_context.cpu_context);
- hv_cpu->clk_evt->event_handler(hv_cpu->clk_evt);
- add_interrupt_randomness(stimer0_vector, 0);
-}
-
-static int hv_ce_set_next_event(unsigned long delta,
- struct clock_event_device *evt)
-{
- u64 current_tick;
-
- WARN_ON(!clockevent_state_oneshot(evt));
-
- current_tick = hyperv_cs->read(NULL);
- current_tick += delta;
- hv_init_timer(0, current_tick);
- return 0;
-}
-
-static int hv_ce_shutdown(struct clock_event_device *evt)
-{
- hv_init_timer(0, 0);
- hv_init_timer_config(0, 0);
- if (direct_mode_enabled)
- hv_disable_stimer0_percpu_irq(stimer0_irq);
-
- return 0;
-}
-
-static int hv_ce_set_oneshot(struct clock_event_device *evt)
-{
- union hv_stimer_config timer_cfg;
-
- timer_cfg.as_uint64 = 0;
- timer_cfg.enable = 1;
- timer_cfg.auto_enable = 1;
- if (direct_mode_enabled) {
- /*
- * When it expires, the timer will directly interrupt
- * on the specified hardware vector/IRQ.
- */
- timer_cfg.direct_mode = 1;
- timer_cfg.apic_vector = stimer0_vector;
- hv_enable_stimer0_percpu_irq(stimer0_irq);
- } else {
- /*
- * When it expires, the timer will generate a VMbus message,
- * to be handled by the normal VMbus interrupt handler.
- */
- timer_cfg.direct_mode = 0;
- timer_cfg.sintx = VMBUS_MESSAGE_SINT;
- }
- hv_init_timer_config(0, timer_cfg.as_uint64);
- return 0;
-}
-
-static void hv_init_clockevent_device(struct clock_event_device *dev, int cpu)
-{
- dev->name = "Hyper-V clockevent";
- dev->features = CLOCK_EVT_FEAT_ONESHOT;
- dev->cpumask = cpumask_of(cpu);
- dev->rating = 1000;
- /*
- * Avoid settint dev->owner = THIS_MODULE deliberately as doing so will
- * result in clockevents_config_and_register() taking additional
- * references to the hv_vmbus module making it impossible to unload.
- */
-
- dev->set_state_shutdown = hv_ce_shutdown;
- dev->set_state_oneshot = hv_ce_set_oneshot;
- dev->set_next_event = hv_ce_set_next_event;
-}
-
-
int hv_synic_alloc(void)
{
int cpu;
@@ -212,14 +112,6 @@ int hv_synic_alloc(void)
tasklet_init(&hv_cpu->msg_dpc,
vmbus_on_msg_dpc, (unsigned long) hv_cpu);
- hv_cpu->clk_evt = kzalloc(sizeof(struct clock_event_device),
- GFP_KERNEL);
- if (hv_cpu->clk_evt == NULL) {
- pr_err("Unable to allocate clock event device\n");
- goto err;
- }
- hv_init_clockevent_device(hv_cpu->clk_evt, cpu);
-
hv_cpu->synic_message_page =
(void *)get_zeroed_page(GFP_ATOMIC);
if (hv_cpu->synic_message_page == NULL) {
@@ -242,11 +134,6 @@ int hv_synic_alloc(void)
INIT_LIST_HEAD(&hv_cpu->chan_list);
}
- if (direct_mode_enabled &&
- hv_setup_stimer0_irq(&stimer0_irq, &stimer0_vector,
- hv_stimer0_isr))
- goto err;
-
return 0;
err:
/*
@@ -265,7 +152,6 @@ void hv_synic_free(void)
struct hv_per_cpu_context *hv_cpu
= per_cpu_ptr(hv_context.cpu_context, cpu);
- kfree(hv_cpu->clk_evt);
free_page((unsigned long)hv_cpu->synic_event_page);
free_page((unsigned long)hv_cpu->synic_message_page);
free_page((unsigned long)hv_cpu->post_msg_page);
@@ -324,36 +210,9 @@ int hv_synic_init(unsigned int cpu)
hv_set_synic_state(sctrl.as_uint64);
- /*
- * Register the per-cpu clockevent source.
- */
- if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE)
- clockevents_config_and_register(hv_cpu->clk_evt,
- HV_TIMER_FREQUENCY,
- HV_MIN_DELTA_TICKS,
- HV_MAX_MAX_DELTA_TICKS);
- return 0;
-}
-
-/*
- * hv_synic_clockevents_cleanup - Cleanup clockevent devices
- */
-void hv_synic_clockevents_cleanup(void)
-{
- int cpu;
+ hv_stimer_init(cpu);
- if (!(ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE))
- return;
-
- if (direct_mode_enabled)
- hv_remove_stimer0_irq(stimer0_irq);
-
- for_each_present_cpu(cpu) {
- struct hv_per_cpu_context *hv_cpu
- = per_cpu_ptr(hv_context.cpu_context, cpu);
-
- clockevents_unbind_device(hv_cpu->clk_evt, cpu);
- }
+ return 0;
}
/*
@@ -401,14 +260,7 @@ int hv_synic_cleanup(unsigned int cpu)
if (channel_found && vmbus_connection.conn_state == CONNECTED)
return -EBUSY;
- /* Turn off clockevent device */
- if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE) {
- struct hv_per_cpu_context *hv_cpu
- = this_cpu_ptr(hv_context.cpu_context);
-
- clockevents_unbind_device(hv_cpu->clk_evt, cpu);
- hv_ce_shutdown(hv_cpu->clk_evt);
- }
+ hv_stimer_cleanup(cpu);
hv_get_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index e5467b8..a8f8aee 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -151,7 +151,6 @@ struct hv_per_cpu_context {
* per-cpu list of the channels based on their CPU affinity.
*/
struct list_head chan_list;
- struct clock_event_device *clk_evt;
};
struct hv_context {
@@ -189,8 +188,6 @@ extern int hv_post_message(union hv_connection_id connection_id,
extern int hv_synic_cleanup(unsigned int cpu);
-extern void hv_synic_clockevents_cleanup(void);
-
/* Interface */
void hv_ringbuffer_pre_init(struct vmbus_channel *channel);
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 1cb9408..89aca5d 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -43,6 +43,7 @@
#include <linux/kdebug.h>
#include <linux/efi.h>
#include <linux/random.h>
+#include <clocksource/hyperv_timer.h>
#include "hyperv_vmbus.h"
struct vmbus_dynid {
@@ -968,17 +969,6 @@ static void vmbus_onmessage_work(struct work_struct *work)
kfree(ctx);
}
-static void hv_process_timer_expiration(struct hv_message *msg,
- struct hv_per_cpu_context *hv_cpu)
-{
- struct clock_event_device *dev = hv_cpu->clk_evt;
-
- if (dev->event_handler)
- dev->event_handler(dev);
-
- vmbus_signal_eom(msg, HVMSG_TIMER_EXPIRED);
-}
-
void vmbus_on_msg_dpc(unsigned long data)
{
struct hv_per_cpu_context *hv_cpu = (void *)data;
@@ -1172,9 +1162,10 @@ static void vmbus_isr(void)
/* Check if there are actual msgs to be processed */
if (msg->header.message_type != HVMSG_NONE) {
- if (msg->header.message_type == HVMSG_TIMER_EXPIRED)
- hv_process_timer_expiration(msg, hv_cpu);
- else
+ if (msg->header.message_type == HVMSG_TIMER_EXPIRED) {
+ hv_stimer0_isr();
+ vmbus_signal_eom(msg, HVMSG_TIMER_EXPIRED);
+ } else
tasklet_schedule(&hv_cpu->msg_dpc);
}
@@ -1276,14 +1267,19 @@ static int vmbus_bus_init(void)
ret = hv_synic_alloc();
if (ret)
goto err_alloc;
+
+ ret = hv_stimer_alloc(VMBUS_MESSAGE_SINT);
+ if (ret < 0)
+ goto err_alloc;
+
/*
- * Initialize the per-cpu interrupt state and
- * connect to the host.
+ * Initialize the per-cpu interrupt state and stimer state.
+ * Then connect to the host.
*/
ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "hyperv/vmbus:online",
hv_synic_init, hv_synic_cleanup);
if (ret < 0)
- goto err_alloc;
+ goto err_cpuhp;
hyperv_cpuhp_online = ret;
ret = vmbus_connect();
@@ -1331,6 +1327,8 @@ static int vmbus_bus_init(void)
err_connect:
cpuhp_remove_state(hyperv_cpuhp_online);
+err_cpuhp:
+ hv_stimer_free();
err_alloc:
hv_synic_free();
hv_remove_vmbus_irq();
@@ -2077,7 +2075,7 @@ static int vmbus_acpi_add(struct acpi_device *device)
static void hv_kexec_handler(void)
{
- hv_synic_clockevents_cleanup();
+ hv_stimer_global_cleanup();
vmbus_initiate_unload(false);
vmbus_connection.conn_state = DISCONNECTED;
/* Make sure conn_state is set as hv_synic_cleanup checks for it */
@@ -2088,6 +2086,8 @@ static void hv_kexec_handler(void)
static void hv_crash_handler(struct pt_regs *regs)
{
+ int cpu;
+
vmbus_initiate_unload(true);
/*
* In crash handler we can't schedule synic cleanup for all CPUs,
@@ -2095,7 +2095,9 @@ static void hv_crash_handler(struct pt_regs *regs)
* for kdump.
*/
vmbus_connection.conn_state = DISCONNECTED;
- hv_synic_cleanup(smp_processor_id());
+ cpu = smp_processor_id();
+ hv_stimer_cleanup(cpu);
+ hv_synic_cleanup(cpu);
hyperv_cleanup();
};
@@ -2144,7 +2146,7 @@ static void __exit vmbus_exit(void)
hv_remove_kexec_handler();
hv_remove_crash_handler();
vmbus_connection.conn_state = DISCONNECTED;
- hv_synic_clockevents_cleanup();
+ hv_stimer_global_cleanup();
vmbus_disconnect();
hv_remove_vmbus_irq();
for_each_online_cpu(cpu) {
diff --git a/include/clocksource/hyperv_timer.h b/include/clocksource/hyperv_timer.h
new file mode 100644
index 0000000..ba5dc17
--- /dev/null
+++ b/include/clocksource/hyperv_timer.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * Definitions for the clocksource provided by the Hyper-V
+ * hypervisor to guest VMs, as described in the Hyper-V Top
+ * Level Functional Spec (TLFS).
+ *
+ * Copyright (C) 2019, Microsoft, Inc.
+ *
+ * Author: Michael Kelley <mikelley@microsoft.com>
+ */
+
+#ifndef __CLKSOURCE_HYPERV_TIMER_H
+#define __CLKSOURCE_HYPERV_TIMER_H
+
+#define HV_MAX_MAX_DELTA_TICKS 0xffffffff
+#define HV_MIN_DELTA_TICKS 1
+
+/* Routines called by the VMbus driver */
+extern int hv_stimer_alloc(int sint);
+extern void hv_stimer_free(void);
+extern int hv_stimer_init(unsigned int cpu);
+extern int hv_stimer_cleanup(unsigned int cpu);
+extern void hv_stimer_global_cleanup(void);
+extern void hv_stimer0_isr(void);
+
+#endif
--
1.8.3.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH v3 2/2] Drivers: hv: Move Hyper-V clocksource code to new clocksource driver
2019-05-27 14:59 [PATCH v3 0/2] Drivers: hv: Move Hyper-V clock/timer code to separate clocksource driver Michael Kelley
2019-05-27 14:59 ` [PATCH v3 1/2] Drivers: hv: Create Hyper-V clocksource driver from existing clockevents code Michael Kelley
@ 2019-05-27 14:59 ` Michael Kelley
2019-05-30 9:48 ` Vitaly Kuznetsov
2019-06-06 16:37 ` [PATCH v3 0/2] Drivers: hv: Move Hyper-V clock/timer code to separate " Sasha Levin
2 siblings, 1 reply; 8+ messages in thread
From: Michael Kelley @ 2019-05-27 14:59 UTC (permalink / raw)
To: will.deacon, marc.zyngier, linux-arm-kernel, gregkh,
linux-kernel, linux-hyperv, olaf, apw, vkuznets, jasowang,
marcelo.cerri, Sunil Muthuswamy, KY Srinivasan
Cc: Michael Kelley, catalin.marinas, mark.rutland
Code for the Hyper-V specific clocksources is currently mixed
in with other Hyper-V code. Move the code to the Hyper-V specific
driver in the "clocksource" directory, while separating out
ISA dependencies so that the clocksource driver remains ISA
independent. Update the Hyper-V initialization code to call
initialization and cleanup routines since the Hyper-V synthetic
timers are not independently enumerated in ACPI. Update Hyper-V
clocksource users KVM and VDSO to get definitions from a 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>
---
arch/x86/entry/vdso/vclock_gettime.c | 1 +
arch/x86/entry/vdso/vma.c | 2 +-
arch/x86/hyperv/hv_init.c | 91 +-----------------------
arch/x86/include/asm/mshyperv.h | 81 +++-------------------
arch/x86/kvm/x86.c | 1 +
drivers/clocksource/hyperv_timer.c | 130 +++++++++++++++++++++++++++++++++++
drivers/hv/hv_util.c | 1 +
include/clocksource/hyperv_timer.h | 78 +++++++++++++++++++++
8 files changed, 226 insertions(+), 159 deletions(-)
diff --git a/arch/x86/entry/vdso/vclock_gettime.c b/arch/x86/entry/vdso/vclock_gettime.c
index 98c7d12..7983ca2 100644
--- a/arch/x86/entry/vdso/vclock_gettime.c
+++ b/arch/x86/entry/vdso/vclock_gettime.c
@@ -21,6 +21,7 @@
#include <linux/math64.h>
#include <linux/time.h>
#include <linux/kernel.h>
+#include <clocksource/hyperv_timer.h>
#define gtod (&VVAR(vsyscall_gtod_data))
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index babc4e7..99b38e9 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -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;
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index e4ba467..79f626a 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -27,64 +27,13 @@
#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);
@@ -353,42 +302,8 @@ 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:
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index cc60e61..f4fa8a9 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -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
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 536b78c..3fbaac0 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -70,6 +70,7 @@
#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"
diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index 30615f3..274614d 100644
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c
@@ -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>
@@ -189,3 +191,131 @@ 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 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 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,
+};
+
+void __init hv_init_clocksource(void)
+{
+#ifdef CONFIG_HYPERV_TSCPAGE
+ if (ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE) {
+
+ u64 tsc_msr;
+ phys_addr_t phys_addr;
+
+ tsc_pg = vmalloc(PAGE_SIZE);
+ if (!tsc_pg)
+ goto register_msr_cs;
+
+ 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;
+ }
+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);
+
+ /*
+ * 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);
diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
index f10eeb1..9eff85e 100644
--- a/drivers/hv/hv_util.c
+++ b/drivers/hv/hv_util.c
@@ -29,6 +29,7 @@
#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"
diff --git a/include/clocksource/hyperv_timer.h b/include/clocksource/hyperv_timer.h
index ba5dc17..e17e8a2 100644
--- a/include/clocksource/hyperv_timer.h
+++ b/include/clocksource/hyperv_timer.h
@@ -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 +28,78 @@
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 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 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
--
1.8.3.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH v3 1/2] Drivers: hv: Create Hyper-V clocksource driver from existing clockevents code
2019-05-27 14:59 ` [PATCH v3 1/2] Drivers: hv: Create Hyper-V clocksource driver from existing clockevents code Michael Kelley
@ 2019-05-30 9:37 ` Vitaly Kuznetsov
0 siblings, 0 replies; 8+ messages in thread
From: Vitaly Kuznetsov @ 2019-05-30 9:37 UTC (permalink / raw)
To: Michael Kelley
Cc: catalin.marinas, mark.rutland, will.deacon, marc.zyngier,
linux-arm-kernel, gregkh, linux-kernel, linux-hyperv, olaf, apw,
jasowang, marcelo.cerri, Sunil Muthuswamy, KY Srinivasan
Michael Kelley <mikelley@microsoft.com> writes:
> Clockevents code for Hyper-V synthetic timers is currently mixed
> in with other Hyper-V code. Move the code to a Hyper-V specific
> driver in the "clocksource" directory. Update the VMbus driver
> to call initialization and cleanup routines since the Hyper-V
> synthetic timers are not independently enumerated in ACPI.
>
> 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>
> ---
> MAINTAINERS | 2 +
> arch/x86/include/asm/hyperv-tlfs.h | 6 ++
> arch/x86/kernel/cpu/mshyperv.c | 2 +
> drivers/clocksource/Makefile | 1 +
> drivers/clocksource/hyperv_timer.c | 191 +++++++++++++++++++++++++++++++++++++
> drivers/hv/Kconfig | 3 +
> drivers/hv/hv.c | 156 +-----------------------------
> drivers/hv/hyperv_vmbus.h | 3 -
> drivers/hv/vmbus_drv.c | 42 ++++----
> include/clocksource/hyperv_timer.h | 27 ++++++
> 10 files changed, 258 insertions(+), 175 deletions(-)
> create mode 100644 drivers/clocksource/hyperv_timer.c
> create mode 100644 include/clocksource/hyperv_timer.h
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 992f1dd..cf2a5b7 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -7294,6 +7294,7 @@ F: arch/x86/include/asm/trace/hyperv.h
> F: arch/x86/include/asm/hyperv-tlfs.h
> F: arch/x86/kernel/cpu/mshyperv.c
> F: arch/x86/hyperv
> +F: drivers/clocksource/hyperv_timer.c
> F: drivers/hid/hid-hyperv.c
> F: drivers/hv/
> F: drivers/input/serio/hyperv-keyboard.c
> @@ -7304,6 +7305,7 @@ F: drivers/uio/uio_hv_generic.c
> F: drivers/video/fbdev/hyperv_fb.c
> F: drivers/iommu/hyperv_iommu.c
> F: net/vmw_vsock/hyperv_transport.c
> +F: include/clocksource/hyperv_timer.h
> F: include/linux/hyperv.h
> F: include/uapi/linux/hyperv.h
> F: tools/hv/
> diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
> index cdf44aa..af78cd7 100644
> --- a/arch/x86/include/asm/hyperv-tlfs.h
> +++ b/arch/x86/include/asm/hyperv-tlfs.h
> @@ -401,6 +401,12 @@ enum HV_GENERIC_SET_FORMAT {
> #define HV_STATUS_INVALID_CONNECTION_ID 18
> #define HV_STATUS_INSUFFICIENT_BUFFERS 19
>
> +/*
> + * The Hyper-V TimeRefCount register and the TSC
> + * page provide a guest VM clock with 100ns tick rate
> + */
> +#define HV_CLOCK_HZ (NSEC_PER_SEC/100)
> +
> typedef struct _HV_REFERENCE_TSC_PAGE {
> __u32 tsc_sequence;
> __u32 res1;
> diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
> index faae611..b18ede4 100644
> --- a/arch/x86/kernel/cpu/mshyperv.c
> +++ b/arch/x86/kernel/cpu/mshyperv.c
> @@ -21,6 +21,7 @@
> #include <linux/irq.h>
> #include <linux/kexec.h>
> #include <linux/i8253.h>
> +#include <linux/random.h>
> #include <asm/processor.h>
> #include <asm/hypervisor.h>
> #include <asm/hyperv-tlfs.h>
> @@ -84,6 +85,7 @@ __visible void __irq_entry hv_stimer0_vector_handler(struct pt_regs *regs)
> inc_irq_stat(hyperv_stimer0_count);
> if (hv_stimer0_handler)
> hv_stimer0_handler();
> + add_interrupt_randomness(HYPERV_STIMER0_VECTOR, 0);
> ack_APIC_irq();
>
> exiting_irq();
> diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
> index 236858f..2b65c5f 100644
> --- a/drivers/clocksource/Makefile
> +++ b/drivers/clocksource/Makefile
> @@ -84,3 +84,4 @@ obj-$(CONFIG_ATCPIT100_TIMER) += timer-atcpit100.o
> obj-$(CONFIG_RISCV_TIMER) += timer-riscv.o
> obj-$(CONFIG_CSKY_MP_TIMER) += timer-mp-csky.o
> obj-$(CONFIG_GX6605S_TIMER) += timer-gx6605s.o
> +obj-$(CONFIG_HYPERV_TIMER) += hyperv_timer.o
> diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
> new file mode 100644
> index 0000000..30615f3
> --- /dev/null
> +++ b/drivers/clocksource/hyperv_timer.c
> @@ -0,0 +1,191 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +/*
> + * Clocksource driver for the synthetic counter and timers
> + * provided by the Hyper-V hypervisor to guest VMs, as described
> + * in the Hyper-V Top Level Functional Spec (TLFS). This driver
> + * is instruction set architecture independent.
> + *
> + * Copyright (C) 2019, Microsoft, Inc.
> + *
> + * Author: Michael Kelley <mikelley@microsoft.com>
> + */
> +
> +#include <linux/percpu.h>
> +#include <linux/cpumask.h>
> +#include <linux/clockchips.h>
> +#include <linux/mm.h>
> +#include <clocksource/hyperv_timer.h>
> +#include <asm/hyperv-tlfs.h>
> +#include <asm/mshyperv.h>
> +
> +static struct clock_event_device __percpu *hv_clock_event;
> +
> +/*
> + * If false, we're using the old mechanism for stimer0 interrupts
> + * where it sends a VMbus message when it expires. The old
> + * mechanism is used when running on older versions of Hyper-V
> + * that don't support Direct Mode. While Hyper-V provides
> + * four stimer's per CPU, Linux uses only stimer0.
> + */
> +static bool direct_mode_enabled;
> +
> +static int stimer0_irq;
> +static int stimer0_vector;
> +static int stimer0_message_sint;
> +
> +/*
> + * ISR for when stimer0 is operating in Direct Mode. Direct Mode
> + * does not use VMbus or any VMbus messages, so process here and not
> + * in the VMbus driver code.
> + */
> +void hv_stimer0_isr(void)
> +{
> + struct clock_event_device *ce;
> +
> + ce = this_cpu_ptr(hv_clock_event);
> + ce->event_handler(ce);
> +}
> +EXPORT_SYMBOL_GPL(hv_stimer0_isr);
> +
> +static int hv_ce_set_next_event(unsigned long delta,
> + struct clock_event_device *evt)
> +{
> + u64 current_tick;
> +
> + WARN_ON(!clockevent_state_oneshot(evt));
> +
> + current_tick = hyperv_cs->read(NULL);
> + current_tick += delta;
> + hv_init_timer(0, current_tick);
> + return 0;
> +}
> +
> +static int hv_ce_shutdown(struct clock_event_device *evt)
> +{
> + hv_init_timer(0, 0);
> + hv_init_timer_config(0, 0);
> + if (direct_mode_enabled)
> + hv_disable_stimer0_percpu_irq(stimer0_irq);
> +
> + return 0;
> +}
> +
> +static int hv_ce_set_oneshot(struct clock_event_device *evt)
> +{
> + union hv_stimer_config timer_cfg;
> +
> + timer_cfg.as_uint64 = 0;
> + timer_cfg.enable = 1;
> + timer_cfg.auto_enable = 1;
> + if (direct_mode_enabled) {
> + /*
> + * When it expires, the timer will directly interrupt
> + * on the specified hardware vector/IRQ.
> + */
> + timer_cfg.direct_mode = 1;
> + timer_cfg.apic_vector = stimer0_vector;
> + hv_enable_stimer0_percpu_irq(stimer0_irq);
> + } else {
> + /*
> + * When it expires, the timer will generate a VMbus message,
> + * to be handled by the normal VMbus interrupt handler.
> + */
> + timer_cfg.direct_mode = 0;
> + timer_cfg.sintx = stimer0_message_sint;
> + }
> + hv_init_timer_config(0, timer_cfg.as_uint64);
> + return 0;
> +}
> +
> +/*
> + * hv_stimer_init - Per-cpu initialization of the clockevent
> + */
> +int hv_stimer_init(unsigned int cpu)
> +{
> + struct clock_event_device *ce;
> +
> + if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE) {
> + ce = per_cpu_ptr(hv_clock_event, cpu);
> + ce->name = "Hyper-V clockevent";
> + ce->features = CLOCK_EVT_FEAT_ONESHOT;
> + ce->cpumask = cpumask_of(cpu);
> + ce->rating = 1000;
> + ce->set_state_shutdown = hv_ce_shutdown;
> + ce->set_state_oneshot = hv_ce_set_oneshot;
> + ce->set_next_event = hv_ce_set_next_event;
> +
> + clockevents_config_and_register(ce,
> + HV_CLOCK_HZ,
> + HV_MIN_DELTA_TICKS,
> + HV_MAX_MAX_DELTA_TICKS);
> + }
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(hv_stimer_init);
> +
> +/*
> + * hv_stimer_cleanup - Per-cpu cleanup of the clockevent
> + */
> +int hv_stimer_cleanup(unsigned int cpu)
> +{
> + struct clock_event_device *ce;
> +
> + /* Turn off clockevent device */
> + if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE) {
> + ce = per_cpu_ptr(hv_clock_event, cpu);
> + clockevents_unbind_device(ce, cpu);
> + hv_ce_shutdown(ce);
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(hv_stimer_cleanup);
> +
> +/* hv_stimer_alloc - Global initialization of the clockevent and stimer0 */
> +int hv_stimer_alloc(int sint)
> +{
> + hv_clock_event = alloc_percpu(struct clock_event_device);
> + if (!hv_clock_event)
> + return -ENOMEM;
> +
> + direct_mode_enabled = ms_hyperv.misc_features &
> + HV_STIMER_DIRECT_MODE_AVAILABLE;
> + if (direct_mode_enabled &&
> + hv_setup_stimer0_irq(&stimer0_irq, &stimer0_vector,
> + hv_stimer0_isr)) {
> + free_percpu(hv_clock_event);
> + return -EINVAL;
> + }
> +
> + stimer0_message_sint = sint;
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(hv_stimer_alloc);
> +
> +/* hv_stimer_free - Free global resources allocated by hv_stimer_alloc() */
> +void hv_stimer_free(void)
> +{
> + if (direct_mode_enabled)
> + hv_remove_stimer0_irq(stimer0_irq);
> + free_percpu(hv_clock_event);
> +}
> +EXPORT_SYMBOL_GPL(hv_stimer_free);
> +
> +/*
> + * Do a global cleanup of clockevents for the cases of kexec and
> + * vmbus exit
> + */
> +void hv_stimer_global_cleanup(void)
> +{
> + int cpu;
> + struct clock_event_device *ce;
> +
> + if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE)
> + for_each_present_cpu(cpu) {
> + ce = per_cpu_ptr(hv_clock_event, cpu);
> + clockevents_unbind_device(ce, cpu);
> + }
> + hv_stimer_free();
> +}
> +EXPORT_SYMBOL_GPL(hv_stimer_global_cleanup);
> diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
> index 1c1a251..c423e57 100644
> --- a/drivers/hv/Kconfig
> +++ b/drivers/hv/Kconfig
> @@ -10,6 +10,9 @@ config HYPERV
> Select this option to run Linux as a Hyper-V client operating
> system.
>
> +config HYPERV_TIMER
> + def_bool HYPERV
> +
> config HYPERV_TSCPAGE
> def_bool HYPERV && X86_64
>
> diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
> index 4565302..bd6452f 100644
> --- a/drivers/hv/hv.c
> +++ b/drivers/hv/hv.c
> @@ -29,6 +29,7 @@
> #include <linux/version.h>
> #include <linux/random.h>
> #include <linux/clockchips.h>
(very minor nit, just an idea for future cleanup):
I think we can throw away
#include <linux/random.h>
#include <linux/clockchips.h>
now.
> +#include <clocksource/hyperv_timer.h>
> #include <asm/mshyperv.h>
> #include "hyperv_vmbus.h"
>
> @@ -36,21 +37,6 @@
> struct hv_context hv_context;
>
> /*
> - * If false, we're using the old mechanism for stimer0 interrupts
> - * where it sends a VMbus message when it expires. The old
> - * mechanism is used when running on older versions of Hyper-V
> - * that don't support Direct Mode. While Hyper-V provides
> - * four stimer's per CPU, Linux uses only stimer0.
> - */
> -static bool direct_mode_enabled;
> -static int stimer0_irq;
> -static int stimer0_vector;
> -
> -#define HV_TIMER_FREQUENCY (10 * 1000 * 1000) /* 100ns period */
> -#define HV_MAX_MAX_DELTA_TICKS 0xffffffff
> -#define HV_MIN_DELTA_TICKS 1
> -
> -/*
> * hv_init - Main initialization routine.
> *
> * This routine must be called before any other routines in here are called
> @@ -60,9 +46,6 @@ int hv_init(void)
> hv_context.cpu_context = alloc_percpu(struct hv_per_cpu_context);
> if (!hv_context.cpu_context)
> return -ENOMEM;
> -
> - direct_mode_enabled = ms_hyperv.misc_features &
> - HV_STIMER_DIRECT_MODE_AVAILABLE;
> return 0;
> }
>
> @@ -101,89 +84,6 @@ int hv_post_message(union hv_connection_id connection_id,
> return status & 0xFFFF;
> }
>
> -/*
> - * ISR for when stimer0 is operating in Direct Mode. Direct Mode
> - * does not use VMbus or any VMbus messages, so process here and not
> - * in the VMbus driver code.
> - */
> -
> -static void hv_stimer0_isr(void)
> -{
> - struct hv_per_cpu_context *hv_cpu;
> -
> - hv_cpu = this_cpu_ptr(hv_context.cpu_context);
> - hv_cpu->clk_evt->event_handler(hv_cpu->clk_evt);
> - add_interrupt_randomness(stimer0_vector, 0);
> -}
> -
> -static int hv_ce_set_next_event(unsigned long delta,
> - struct clock_event_device *evt)
> -{
> - u64 current_tick;
> -
> - WARN_ON(!clockevent_state_oneshot(evt));
> -
> - current_tick = hyperv_cs->read(NULL);
> - current_tick += delta;
> - hv_init_timer(0, current_tick);
> - return 0;
> -}
> -
> -static int hv_ce_shutdown(struct clock_event_device *evt)
> -{
> - hv_init_timer(0, 0);
> - hv_init_timer_config(0, 0);
> - if (direct_mode_enabled)
> - hv_disable_stimer0_percpu_irq(stimer0_irq);
> -
> - return 0;
> -}
> -
> -static int hv_ce_set_oneshot(struct clock_event_device *evt)
> -{
> - union hv_stimer_config timer_cfg;
> -
> - timer_cfg.as_uint64 = 0;
> - timer_cfg.enable = 1;
> - timer_cfg.auto_enable = 1;
> - if (direct_mode_enabled) {
> - /*
> - * When it expires, the timer will directly interrupt
> - * on the specified hardware vector/IRQ.
> - */
> - timer_cfg.direct_mode = 1;
> - timer_cfg.apic_vector = stimer0_vector;
> - hv_enable_stimer0_percpu_irq(stimer0_irq);
> - } else {
> - /*
> - * When it expires, the timer will generate a VMbus message,
> - * to be handled by the normal VMbus interrupt handler.
> - */
> - timer_cfg.direct_mode = 0;
> - timer_cfg.sintx = VMBUS_MESSAGE_SINT;
> - }
> - hv_init_timer_config(0, timer_cfg.as_uint64);
> - return 0;
> -}
> -
> -static void hv_init_clockevent_device(struct clock_event_device *dev, int cpu)
> -{
> - dev->name = "Hyper-V clockevent";
> - dev->features = CLOCK_EVT_FEAT_ONESHOT;
> - dev->cpumask = cpumask_of(cpu);
> - dev->rating = 1000;
> - /*
> - * Avoid settint dev->owner = THIS_MODULE deliberately as doing so will
> - * result in clockevents_config_and_register() taking additional
> - * references to the hv_vmbus module making it impossible to unload.
> - */
> -
> - dev->set_state_shutdown = hv_ce_shutdown;
> - dev->set_state_oneshot = hv_ce_set_oneshot;
> - dev->set_next_event = hv_ce_set_next_event;
> -}
> -
> -
> int hv_synic_alloc(void)
> {
> int cpu;
> @@ -212,14 +112,6 @@ int hv_synic_alloc(void)
> tasklet_init(&hv_cpu->msg_dpc,
> vmbus_on_msg_dpc, (unsigned long) hv_cpu);
>
> - hv_cpu->clk_evt = kzalloc(sizeof(struct clock_event_device),
> - GFP_KERNEL);
> - if (hv_cpu->clk_evt == NULL) {
> - pr_err("Unable to allocate clock event device\n");
> - goto err;
> - }
> - hv_init_clockevent_device(hv_cpu->clk_evt, cpu);
> -
> hv_cpu->synic_message_page =
> (void *)get_zeroed_page(GFP_ATOMIC);
> if (hv_cpu->synic_message_page == NULL) {
> @@ -242,11 +134,6 @@ int hv_synic_alloc(void)
> INIT_LIST_HEAD(&hv_cpu->chan_list);
> }
>
> - if (direct_mode_enabled &&
> - hv_setup_stimer0_irq(&stimer0_irq, &stimer0_vector,
> - hv_stimer0_isr))
> - goto err;
> -
> return 0;
> err:
> /*
> @@ -265,7 +152,6 @@ void hv_synic_free(void)
> struct hv_per_cpu_context *hv_cpu
> = per_cpu_ptr(hv_context.cpu_context, cpu);
>
> - kfree(hv_cpu->clk_evt);
> free_page((unsigned long)hv_cpu->synic_event_page);
> free_page((unsigned long)hv_cpu->synic_message_page);
> free_page((unsigned long)hv_cpu->post_msg_page);
> @@ -324,36 +210,9 @@ int hv_synic_init(unsigned int cpu)
>
> hv_set_synic_state(sctrl.as_uint64);
>
> - /*
> - * Register the per-cpu clockevent source.
> - */
> - if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE)
> - clockevents_config_and_register(hv_cpu->clk_evt,
> - HV_TIMER_FREQUENCY,
> - HV_MIN_DELTA_TICKS,
> - HV_MAX_MAX_DELTA_TICKS);
> - return 0;
> -}
> -
> -/*
> - * hv_synic_clockevents_cleanup - Cleanup clockevent devices
> - */
> -void hv_synic_clockevents_cleanup(void)
> -{
> - int cpu;
> + hv_stimer_init(cpu);
>
> - if (!(ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE))
> - return;
> -
> - if (direct_mode_enabled)
> - hv_remove_stimer0_irq(stimer0_irq);
> -
> - for_each_present_cpu(cpu) {
> - struct hv_per_cpu_context *hv_cpu
> - = per_cpu_ptr(hv_context.cpu_context, cpu);
> -
> - clockevents_unbind_device(hv_cpu->clk_evt, cpu);
> - }
> + return 0;
> }
>
> /*
> @@ -401,14 +260,7 @@ int hv_synic_cleanup(unsigned int cpu)
> if (channel_found && vmbus_connection.conn_state == CONNECTED)
> return -EBUSY;
>
> - /* Turn off clockevent device */
> - if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE) {
> - struct hv_per_cpu_context *hv_cpu
> - = this_cpu_ptr(hv_context.cpu_context);
> -
> - clockevents_unbind_device(hv_cpu->clk_evt, cpu);
> - hv_ce_shutdown(hv_cpu->clk_evt);
> - }
> + hv_stimer_cleanup(cpu);
>
> hv_get_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
>
> diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
> index e5467b8..a8f8aee 100644
> --- a/drivers/hv/hyperv_vmbus.h
> +++ b/drivers/hv/hyperv_vmbus.h
> @@ -151,7 +151,6 @@ struct hv_per_cpu_context {
> * per-cpu list of the channels based on their CPU affinity.
> */
> struct list_head chan_list;
> - struct clock_event_device *clk_evt;
> };
>
> struct hv_context {
> @@ -189,8 +188,6 @@ extern int hv_post_message(union hv_connection_id connection_id,
>
> extern int hv_synic_cleanup(unsigned int cpu);
>
> -extern void hv_synic_clockevents_cleanup(void);
> -
> /* Interface */
>
> void hv_ringbuffer_pre_init(struct vmbus_channel *channel);
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index 1cb9408..89aca5d 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -43,6 +43,7 @@
> #include <linux/kdebug.h>
> #include <linux/efi.h>
> #include <linux/random.h>
> +#include <clocksource/hyperv_timer.h>
> #include "hyperv_vmbus.h"
>
> struct vmbus_dynid {
> @@ -968,17 +969,6 @@ static void vmbus_onmessage_work(struct work_struct *work)
> kfree(ctx);
> }
>
> -static void hv_process_timer_expiration(struct hv_message *msg,
> - struct hv_per_cpu_context *hv_cpu)
> -{
> - struct clock_event_device *dev = hv_cpu->clk_evt;
> -
> - if (dev->event_handler)
> - dev->event_handler(dev);
> -
> - vmbus_signal_eom(msg, HVMSG_TIMER_EXPIRED);
> -}
> -
> void vmbus_on_msg_dpc(unsigned long data)
> {
> struct hv_per_cpu_context *hv_cpu = (void *)data;
> @@ -1172,9 +1162,10 @@ static void vmbus_isr(void)
>
> /* Check if there are actual msgs to be processed */
> if (msg->header.message_type != HVMSG_NONE) {
> - if (msg->header.message_type == HVMSG_TIMER_EXPIRED)
> - hv_process_timer_expiration(msg, hv_cpu);
> - else
> + if (msg->header.message_type == HVMSG_TIMER_EXPIRED) {
> + hv_stimer0_isr();
> + vmbus_signal_eom(msg, HVMSG_TIMER_EXPIRED);
> + } else
> tasklet_schedule(&hv_cpu->msg_dpc);
> }
>
> @@ -1276,14 +1267,19 @@ static int vmbus_bus_init(void)
> ret = hv_synic_alloc();
> if (ret)
> goto err_alloc;
> +
> + ret = hv_stimer_alloc(VMBUS_MESSAGE_SINT);
> + if (ret < 0)
> + goto err_alloc;
> +
> /*
> - * Initialize the per-cpu interrupt state and
> - * connect to the host.
> + * Initialize the per-cpu interrupt state and stimer state.
> + * Then connect to the host.
> */
> ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "hyperv/vmbus:online",
> hv_synic_init, hv_synic_cleanup);
> if (ret < 0)
> - goto err_alloc;
> + goto err_cpuhp;
> hyperv_cpuhp_online = ret;
>
> ret = vmbus_connect();
> @@ -1331,6 +1327,8 @@ static int vmbus_bus_init(void)
>
> err_connect:
> cpuhp_remove_state(hyperv_cpuhp_online);
> +err_cpuhp:
> + hv_stimer_free();
> err_alloc:
> hv_synic_free();
> hv_remove_vmbus_irq();
> @@ -2077,7 +2075,7 @@ static int vmbus_acpi_add(struct acpi_device *device)
>
> static void hv_kexec_handler(void)
> {
> - hv_synic_clockevents_cleanup();
> + hv_stimer_global_cleanup();
> vmbus_initiate_unload(false);
> vmbus_connection.conn_state = DISCONNECTED;
> /* Make sure conn_state is set as hv_synic_cleanup checks for it */
> @@ -2088,6 +2086,8 @@ static void hv_kexec_handler(void)
>
> static void hv_crash_handler(struct pt_regs *regs)
> {
> + int cpu;
> +
> vmbus_initiate_unload(true);
> /*
> * In crash handler we can't schedule synic cleanup for all CPUs,
> @@ -2095,7 +2095,9 @@ static void hv_crash_handler(struct pt_regs *regs)
> * for kdump.
> */
> vmbus_connection.conn_state = DISCONNECTED;
> - hv_synic_cleanup(smp_processor_id());
> + cpu = smp_processor_id();
> + hv_stimer_cleanup(cpu);
> + hv_synic_cleanup(cpu);
> hyperv_cleanup();
> };
>
> @@ -2144,7 +2146,7 @@ static void __exit vmbus_exit(void)
> hv_remove_kexec_handler();
> hv_remove_crash_handler();
> vmbus_connection.conn_state = DISCONNECTED;
> - hv_synic_clockevents_cleanup();
> + hv_stimer_global_cleanup();
> vmbus_disconnect();
> hv_remove_vmbus_irq();
> for_each_online_cpu(cpu) {
> diff --git a/include/clocksource/hyperv_timer.h b/include/clocksource/hyperv_timer.h
> new file mode 100644
> index 0000000..ba5dc17
> --- /dev/null
> +++ b/include/clocksource/hyperv_timer.h
> @@ -0,0 +1,27 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +/*
> + * Definitions for the clocksource provided by the Hyper-V
> + * hypervisor to guest VMs, as described in the Hyper-V Top
> + * Level Functional Spec (TLFS).
> + *
> + * Copyright (C) 2019, Microsoft, Inc.
> + *
> + * Author: Michael Kelley <mikelley@microsoft.com>
> + */
> +
> +#ifndef __CLKSOURCE_HYPERV_TIMER_H
> +#define __CLKSOURCE_HYPERV_TIMER_H
> +
> +#define HV_MAX_MAX_DELTA_TICKS 0xffffffff
> +#define HV_MIN_DELTA_TICKS 1
> +
> +/* Routines called by the VMbus driver */
> +extern int hv_stimer_alloc(int sint);
> +extern void hv_stimer_free(void);
> +extern int hv_stimer_init(unsigned int cpu);
> +extern int hv_stimer_cleanup(unsigned int cpu);
> +extern void hv_stimer_global_cleanup(void);
> +extern void hv_stimer0_isr(void);
> +
> +#endif
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
--
Vitaly
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v3 2/2] Drivers: hv: Move Hyper-V clocksource code to new clocksource driver
2019-05-27 14:59 ` [PATCH v3 2/2] Drivers: hv: Move Hyper-V clocksource code to new clocksource driver Michael Kelley
@ 2019-05-30 9:48 ` Vitaly Kuznetsov
2019-05-30 12:39 ` Michael Kelley
0 siblings, 1 reply; 8+ messages in thread
From: Vitaly Kuznetsov @ 2019-05-30 9:48 UTC (permalink / raw)
To: Michael Kelley
Cc: catalin.marinas, mark.rutland, will.deacon, marc.zyngier,
linux-arm-kernel, gregkh, linux-kernel, linux-hyperv, olaf, apw,
jasowang, marcelo.cerri, Sunil Muthuswamy, KY Srinivasan
Michael Kelley <mikelley@microsoft.com> writes:
> Code for the Hyper-V specific clocksources is currently mixed
> in with other Hyper-V code. Move the code to the Hyper-V specific
> driver in the "clocksource" directory, while separating out
> ISA dependencies so that the clocksource driver remains ISA
> independent. Update the Hyper-V initialization code to call
> initialization and cleanup routines since the Hyper-V synthetic
> timers are not independently enumerated in ACPI. Update Hyper-V
> clocksource users KVM and VDSO to get definitions from a 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>
> ---
> arch/x86/entry/vdso/vclock_gettime.c | 1 +
> arch/x86/entry/vdso/vma.c | 2 +-
> arch/x86/hyperv/hv_init.c | 91 +-----------------------
> arch/x86/include/asm/mshyperv.h | 81 +++-------------------
> arch/x86/kvm/x86.c | 1 +
> drivers/clocksource/hyperv_timer.c | 130 +++++++++++++++++++++++++++++++++++
> drivers/hv/hv_util.c | 1 +
> include/clocksource/hyperv_timer.h | 78 +++++++++++++++++++++
> 8 files changed, 226 insertions(+), 159 deletions(-)
>
> diff --git a/arch/x86/entry/vdso/vclock_gettime.c b/arch/x86/entry/vdso/vclock_gettime.c
> index 98c7d12..7983ca2 100644
> --- a/arch/x86/entry/vdso/vclock_gettime.c
> +++ b/arch/x86/entry/vdso/vclock_gettime.c
> @@ -21,6 +21,7 @@
> #include <linux/math64.h>
> #include <linux/time.h>
> #include <linux/kernel.h>
> +#include <clocksource/hyperv_timer.h>
>
> #define gtod (&VVAR(vsyscall_gtod_data))
>
> diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
> index babc4e7..99b38e9 100644
> --- a/arch/x86/entry/vdso/vma.c
> +++ b/arch/x86/entry/vdso/vma.c
> @@ -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;
> diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
> index e4ba467..79f626a 100644
> --- a/arch/x86/hyperv/hv_init.c
> +++ b/arch/x86/hyperv/hv_init.c
> @@ -27,64 +27,13 @@
> #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);
> @@ -353,42 +302,8 @@ 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:
> diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
> index cc60e61..f4fa8a9 100644
> --- a/arch/x86/include/asm/mshyperv.h
> +++ b/arch/x86/include/asm/mshyperv.h
> @@ -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
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 536b78c..3fbaac0 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -70,6 +70,7 @@
> #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"
> diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
> index 30615f3..274614d 100644
> --- a/drivers/clocksource/hyperv_timer.c
> +++ b/drivers/clocksource/hyperv_timer.c
> @@ -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>
> @@ -189,3 +191,131 @@ 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 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 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,
> +};
> +
> +void __init hv_init_clocksource(void)
> +{
> +#ifdef CONFIG_HYPERV_TSCPAGE
> + if (ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE) {
> +
> + u64 tsc_msr;
> + phys_addr_t phys_addr;
> +
> + tsc_pg = vmalloc(PAGE_SIZE);
> + if (!tsc_pg)
> + goto register_msr_cs;
> +
> + 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;
> + }
> +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);
> +
> + /*
> + * 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);
I'm not sure about ARM, but MSR-based clocksource would be a really bad
choice for sched clock on x86, this will slow things down
significantly. Luckily, as you're validly stating above,
sched_clock_register() is a no-op on x86 as we don't define
CONFIG_GENERIC_SCHED_CLOCK.
Can we actually *not* do sched_clock_register() in case
TSC page is unavailable (and revert to counting jiffies or whatever)?
> + }
> +}
> +EXPORT_SYMBOL_GPL(hv_init_clocksource);
> diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
> index f10eeb1..9eff85e 100644
> --- a/drivers/hv/hv_util.c
> +++ b/drivers/hv/hv_util.c
> @@ -29,6 +29,7 @@
> #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"
> diff --git a/include/clocksource/hyperv_timer.h b/include/clocksource/hyperv_timer.h
> index ba5dc17..e17e8a2 100644
> --- a/include/clocksource/hyperv_timer.h
> +++ b/include/clocksource/hyperv_timer.h
> @@ -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 +28,78 @@
> 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 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 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
With the (theoretical) question above answered,
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
--
Vitaly
^ permalink raw reply [flat|nested] 8+ messages in thread
* RE: [PATCH v3 2/2] Drivers: hv: Move Hyper-V clocksource code to new clocksource driver
2019-05-30 9:48 ` Vitaly Kuznetsov
@ 2019-05-30 12:39 ` Michael Kelley
2019-05-30 13:51 ` Vitaly Kuznetsov
0 siblings, 1 reply; 8+ messages in thread
From: Michael Kelley @ 2019-05-30 12:39 UTC (permalink / raw)
To: vkuznets
Cc: catalin.marinas, mark.rutland, will.deacon, marc.zyngier,
linux-arm-kernel, gregkh, linux-kernel, linux-hyperv, olaf, apw,
jasowang, marcelo.cerri, Sunil Muthuswamy, KY Srinivasan
From: Vitaly Kuznetsov <vkuznets@redhat.com> Sent: Thursday, May 30, 2019 2:48 AM
> > + /*
> > + * 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);
>
> I'm not sure about ARM, but MSR-based clocksource would be a really bad
> choice for sched clock on x86, this will slow things down
> significantly. Luckily, as you're validly stating above,
> sched_clock_register() is a no-op on x86 as we don't define
> CONFIG_GENERIC_SCHED_CLOCK.
>
> Can we actually *not* do sched_clock_register() in case
> TSC page is unavailable (and revert to counting jiffies or whatever)?
>
We can't skip the sched_clock_register() on ARM64 because it
does define CONFIG_GENERIC_SCHED_CLOCK. However, Hyper-V
should always provide REFERENCE_TSC_AVAILALBE on ARM64,
so we should never end up in the MSR-based code on ARM64.
Arguably that means the call to sched_clock_register() could be
removed since it's a no-op on x86. But I'd like to keep it for symmetry
and in case there's a testing/debugging situation on ARM64 where
we want to clear REFERENCE_TSC_AVAILABLE and go down the
MSR-based code path.
Michael
^ permalink raw reply [flat|nested] 8+ messages in thread
* RE: [PATCH v3 2/2] Drivers: hv: Move Hyper-V clocksource code to new clocksource driver
2019-05-30 12:39 ` Michael Kelley
@ 2019-05-30 13:51 ` Vitaly Kuznetsov
0 siblings, 0 replies; 8+ messages in thread
From: Vitaly Kuznetsov @ 2019-05-30 13:51 UTC (permalink / raw)
To: Michael Kelley
Cc: catalin.marinas, mark.rutland, will.deacon, marc.zyngier,
linux-arm-kernel, gregkh, linux-kernel, linux-hyperv, olaf, apw,
jasowang, marcelo.cerri, Sunil Muthuswamy, KY Srinivasan
Michael Kelley <mikelley@microsoft.com> writes:
> From: Vitaly Kuznetsov <vkuznets@redhat.com> Sent: Thursday, May 30, 2019 2:48 AM
>> > + /*
>> > + * 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);
>>
>> I'm not sure about ARM, but MSR-based clocksource would be a really bad
>> choice for sched clock on x86, this will slow things down
>> significantly. Luckily, as you're validly stating above,
>> sched_clock_register() is a no-op on x86 as we don't define
>> CONFIG_GENERIC_SCHED_CLOCK.
>>
>> Can we actually *not* do sched_clock_register() in case
>> TSC page is unavailable (and revert to counting jiffies or whatever)?
>>
>
> We can't skip the sched_clock_register() on ARM64 because it
> does define CONFIG_GENERIC_SCHED_CLOCK. However, Hyper-V
> should always provide REFERENCE_TSC_AVAILALBE on ARM64,
> so we should never end up in the MSR-based code on ARM64.
> Arguably that means the call to sched_clock_register() could be
> removed since it's a no-op on x86. But I'd like to keep it for symmetry
> and in case there's a testing/debugging situation on ARM64 where
> we want to clear REFERENCE_TSC_AVAILABLE and go down the
> MSR-based code path.
Ok, so it is just a fall-back and not going to be actively used. Thanks!
--
Vitaly
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v3 0/2] Drivers: hv: Move Hyper-V clock/timer code to separate clocksource driver
2019-05-27 14:59 [PATCH v3 0/2] Drivers: hv: Move Hyper-V clock/timer code to separate clocksource driver Michael Kelley
2019-05-27 14:59 ` [PATCH v3 1/2] Drivers: hv: Create Hyper-V clocksource driver from existing clockevents code Michael Kelley
2019-05-27 14:59 ` [PATCH v3 2/2] Drivers: hv: Move Hyper-V clocksource code to new clocksource driver Michael Kelley
@ 2019-06-06 16:37 ` Sasha Levin
2 siblings, 0 replies; 8+ messages in thread
From: Sasha Levin @ 2019-06-06 16:37 UTC (permalink / raw)
To: Michael Kelley
Cc: will.deacon, marc.zyngier, linux-arm-kernel, gregkh,
linux-kernel, linux-hyperv, olaf, apw, vkuznets, jasowang,
marcelo.cerri, Sunil Muthuswamy, KY Srinivasan, catalin.marinas,
mark.rutland
On Mon, May 27, 2019 at 02:59:07PM +0000, Michael Kelley wrote:
>This patch series moves Hyper-V clock/timer code to a separate Hyper-V
>clocksource driver. Previously, Hyper-V clock/timer code and data
>structures were mixed in with other Hyper-V code in the ISA independent
>drivers/hv code as well as in arch dependent code. The new Hyper-V
>clocksource driver is ISA independent, with a just few dependencies on
>arch specific functions. The patch series does not change any behavior
>or functionality -- it only reorganizes the existing code and fixes up
>the linkages. A few places outside of Hyper-V code are fixed up to use
>the new #include file structure.
>
>This restructuring is in response to Marc Zyngier's review comments
>on supporting Hyper-V running on ARM64, and is a good idea in general.
>It increases the amount of code shared between the x86 and ARM64
>architectures, and reduces the size of the new code for supporting
>Hyper-V on ARM64. A new version of the Hyper-V on ARM64 patches will
>follow once this clocksource restructuring is accepted.
>
>The code is diff'ed against Linux 5.2.0-rc1-next-20190524.
>
>Changes in v3:
>* Removed boolean argument to hv_init_clocksource(). Always call
>sched_clock_register, which is needed on ARM64 but a no-op on x86.
>* Removed separate cpuhp setup in hv_stimer_alloc() and instead
>directly call hv_stimer_init() and hv_stimer_cleanup() from
>corresponding VMbus functions. This more closely matches original
>code and avoids clocksource stop/restart problems on ARM64 when
>VMbus code denies CPU offlining request.
>
>Changes in v2:
>* Revised commit short descriptions so the distinction between
>the first and second patches is clearer [GregKH]
>* Renamed new clocksource driver files and functions to use
>existing "timer" and "stimer" names instead of introducing
>"syntimer". [Vitaly Kuznetsov]
>* Introduced CONFIG_HYPER_TIMER to fix build problem when
>CONFIG_HYPERV=m [Vitaly Kuznetsov]
>* Added "Suggested-by: Marc Zyngier"
>
>Michael Kelley (2):
> Drivers: hv: Create Hyper-V clocksource driver from existing
> clockevents code
> Drivers: hv: Move Hyper-V clocksource code to new clocksource driver
>
> MAINTAINERS | 2 +
> arch/x86/entry/vdso/vclock_gettime.c | 1 +
> arch/x86/entry/vdso/vma.c | 2 +-
> arch/x86/hyperv/hv_init.c | 91 +---------
> arch/x86/include/asm/hyperv-tlfs.h | 6 +
> arch/x86/include/asm/mshyperv.h | 81 ++-------
> arch/x86/kernel/cpu/mshyperv.c | 2 +
> arch/x86/kvm/x86.c | 1 +
> drivers/clocksource/Makefile | 1 +
> drivers/clocksource/hyperv_timer.c | 321 +++++++++++++++++++++++++++++++++++
> drivers/hv/Kconfig | 3 +
> drivers/hv/hv.c | 156 +----------------
> drivers/hv/hv_util.c | 1 +
> drivers/hv/hyperv_vmbus.h | 3 -
> drivers/hv/vmbus_drv.c | 42 ++---
> include/clocksource/hyperv_timer.h | 105 ++++++++++++
> 16 files changed, 484 insertions(+), 334 deletions(-)
> create mode 100644 drivers/clocksource/hyperv_timer.c
> create mode 100644 include/clocksource/hyperv_timer.h
Queued for hyperv-next, thanks!
--
Thanks,
Sasha
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2019-06-06 16:37 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-05-27 14:59 [PATCH v3 0/2] Drivers: hv: Move Hyper-V clock/timer code to separate clocksource driver Michael Kelley
2019-05-27 14:59 ` [PATCH v3 1/2] Drivers: hv: Create Hyper-V clocksource driver from existing clockevents code Michael Kelley
2019-05-30 9:37 ` Vitaly Kuznetsov
2019-05-27 14:59 ` [PATCH v3 2/2] Drivers: hv: Move Hyper-V clocksource code to new clocksource driver Michael Kelley
2019-05-30 9:48 ` Vitaly Kuznetsov
2019-05-30 12:39 ` Michael Kelley
2019-05-30 13:51 ` Vitaly Kuznetsov
2019-06-06 16:37 ` [PATCH v3 0/2] Drivers: hv: Move Hyper-V clock/timer code to separate " Sasha Levin
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