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Commit 4061ed9e authored by K. Y. Srinivasan's avatar K. Y. Srinivasan Committed by Greg Kroah-Hartman
Browse files

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: default avatarK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ab3de22b

arch/x86/include/uapi/asm/hyperv.h

+11 −0
Original line number Diff line number Diff line
@@ -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

drivers/hv/hv.c

+78 −0
Original line number Diff line number Diff line
@@ -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;

}

drivers/hv/hyperv_vmbus.h

+21 −0
Original line number Diff line number Diff line
@@ -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;

drivers/hv/vmbus_drv.c

+35 −2
Original line number Diff line number Diff line
@@ -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();
@@ -667,9 +696,13 @@ 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)

	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);

	}

}



/*

 * vmbus_bus_init -Main vmbus driver initialization routine.