Drivers: hv: vmbus: Implement a clockevent device

Implement a clockevent device based on the timer support available on
Hyper-V.
In this version of the patch I have addressed Jason's review comments.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
K. Y. Srinivasan 2015-01-09 23:54:32 -08:00 committed by Greg Kroah-Hartman
parent ab3de22bb4
commit 4061ed9e2a
4 changed files with 145 additions and 2 deletions

View file

@ -187,6 +187,17 @@
#define HV_X64_MSR_SINT14 0x4000009E
#define HV_X64_MSR_SINT15 0x4000009F
/*
* Synthetic Timer MSRs. Four timers per vcpu.
*/
#define HV_X64_MSR_STIMER0_CONFIG 0x400000B0
#define HV_X64_MSR_STIMER0_COUNT 0x400000B1
#define HV_X64_MSR_STIMER1_CONFIG 0x400000B2
#define HV_X64_MSR_STIMER1_COUNT 0x400000B3
#define HV_X64_MSR_STIMER2_CONFIG 0x400000B4
#define HV_X64_MSR_STIMER2_COUNT 0x400000B5
#define HV_X64_MSR_STIMER3_CONFIG 0x400000B6
#define HV_X64_MSR_STIMER3_COUNT 0x400000B7
#define HV_X64_MSR_HYPERCALL_ENABLE 0x00000001
#define HV_X64_MSR_HYPERCALL_PAGE_ADDRESS_SHIFT 12

View file

@ -28,7 +28,9 @@
#include <linux/hyperv.h>
#include <linux/version.h>
#include <linux/interrupt.h>
#include <linux/clockchips.h>
#include <asm/hyperv.h>
#include <asm/mshyperv.h>
#include "hyperv_vmbus.h"
/* The one and only */
@ -37,6 +39,10 @@ struct hv_context hv_context = {
.hypercall_page = NULL,
};
#define HV_TIMER_FREQUENCY (10 * 1000 * 1000) /* 100ns period */
#define HV_MAX_MAX_DELTA_TICKS 0xffffffff
#define HV_MIN_DELTA_TICKS 1
/*
* query_hypervisor_info - Get version info of the windows hypervisor
*/
@ -144,6 +150,8 @@ int hv_init(void)
sizeof(int) * NR_CPUS);
memset(hv_context.event_dpc, 0,
sizeof(void *) * NR_CPUS);
memset(hv_context.clk_evt, 0,
sizeof(void *) * NR_CPUS);
max_leaf = query_hypervisor_info();
@ -258,10 +266,63 @@ u16 hv_signal_event(void *con_id)
return status;
}
static int hv_ce_set_next_event(unsigned long delta,
struct clock_event_device *evt)
{
cycle_t current_tick;
WARN_ON(evt->mode != CLOCK_EVT_MODE_ONESHOT);
rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
current_tick += delta;
wrmsrl(HV_X64_MSR_STIMER0_COUNT, current_tick);
return 0;
}
static void hv_ce_setmode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
union hv_timer_config timer_cfg;
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
/* unsupported */
break;
case CLOCK_EVT_MODE_ONESHOT:
timer_cfg.enable = 1;
timer_cfg.auto_enable = 1;
timer_cfg.sintx = VMBUS_MESSAGE_SINT;
wrmsrl(HV_X64_MSR_STIMER0_CONFIG, timer_cfg.as_uint64);
break;
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
wrmsrl(HV_X64_MSR_STIMER0_COUNT, 0);
wrmsrl(HV_X64_MSR_STIMER0_CONFIG, 0);
break;
case CLOCK_EVT_MODE_RESUME:
break;
}
}
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;
dev->owner = THIS_MODULE;
dev->set_mode = hv_ce_setmode;
dev->set_next_event = hv_ce_set_next_event;
}
int hv_synic_alloc(void)
{
size_t size = sizeof(struct tasklet_struct);
size_t ced_size = sizeof(struct clock_event_device);
int cpu;
for_each_online_cpu(cpu) {
@ -272,6 +333,13 @@ int hv_synic_alloc(void)
}
tasklet_init(hv_context.event_dpc[cpu], vmbus_on_event, cpu);
hv_context.clk_evt[cpu] = kzalloc(ced_size, GFP_ATOMIC);
if (hv_context.clk_evt[cpu] == NULL) {
pr_err("Unable to allocate clock event device\n");
goto err;
}
hv_init_clockevent_device(hv_context.clk_evt[cpu], cpu);
hv_context.synic_message_page[cpu] =
(void *)get_zeroed_page(GFP_ATOMIC);
@ -305,6 +373,7 @@ int hv_synic_alloc(void)
static void hv_synic_free_cpu(int cpu)
{
kfree(hv_context.event_dpc[cpu]);
kfree(hv_context.clk_evt[cpu]);
if (hv_context.synic_event_page[cpu])
free_page((unsigned long)hv_context.synic_event_page[cpu]);
if (hv_context.synic_message_page[cpu])
@ -388,6 +457,15 @@ void hv_synic_init(void *arg)
hv_context.vp_index[cpu] = (u32)vp_index;
INIT_LIST_HEAD(&hv_context.percpu_list[cpu]);
/*
* Register the per-cpu clockevent source.
*/
if (ms_hyperv.features & HV_X64_MSR_SYNTIMER_AVAILABLE)
clockevents_config_and_register(hv_context.clk_evt[cpu],
HV_TIMER_FREQUENCY,
HV_MIN_DELTA_TICKS,
HV_MAX_MAX_DELTA_TICKS);
return;
}

View file

@ -178,6 +178,23 @@ struct hv_message_header {
};
};
/*
* Timer configuration register.
*/
union hv_timer_config {
u64 as_uint64;
struct {
u64 enable:1;
u64 periodic:1;
u64 lazy:1;
u64 auto_enable:1;
u64 reserved_z0:12;
u64 sintx:4;
u64 reserved_z1:44;
};
};
/* Define timer message payload structure. */
struct hv_timer_message_payload {
u32 timer_index;
@ -519,6 +536,10 @@ struct hv_context {
* buffer to post messages to the host.
*/
void *post_msg_page[NR_CPUS];
/*
* Support PV clockevent device.
*/
struct clock_event_device *clk_evt[NR_CPUS];
};
extern struct hv_context hv_context;

View file

@ -32,6 +32,7 @@
#include <linux/completion.h>
#include <linux/hyperv.h>
#include <linux/kernel_stat.h>
#include <linux/clockchips.h>
#include <asm/hyperv.h>
#include <asm/hypervisor.h>
#include <asm/mshyperv.h>
@ -578,6 +579,34 @@ static void vmbus_onmessage_work(struct work_struct *work)
kfree(ctx);
}
void hv_process_timer_expiration(struct hv_message *msg, int cpu)
{
struct clock_event_device *dev = hv_context.clk_evt[cpu];
if (dev->event_handler)
dev->event_handler(dev);
msg->header.message_type = HVMSG_NONE;
/*
* Make sure the write to MessageType (ie set to
* HVMSG_NONE) happens before we read the
* MessagePending and EOMing. Otherwise, the EOMing
* will not deliver any more messages since there is
* no empty slot
*/
mb();
if (msg->header.message_flags.msg_pending) {
/*
* This will cause message queue rescan to
* possibly deliver another msg from the
* hypervisor
*/
wrmsrl(HV_X64_MSR_EOM, 0);
}
}
static void vmbus_on_msg_dpc(unsigned long data)
{
int cpu = smp_processor_id();
@ -667,8 +696,12 @@ static void vmbus_isr(void)
msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
/* Check if there are actual msgs to be processed */
if (msg->header.message_type != HVMSG_NONE)
tasklet_schedule(&msg_dpc);
if (msg->header.message_type != HVMSG_NONE) {
if (msg->header.message_type == HVMSG_TIMER_EXPIRED)
hv_process_timer_expiration(msg, cpu);
else
tasklet_schedule(&msg_dpc);
}
}
/*