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
Greg Kroah-Hartman
parent
ab3de22bb4
commit
4061ed9e2a
4 changed files with 145 additions and 2 deletions
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@ -187,6 +187,17 @@
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#define HV_X64_MSR_SINT14 0x4000009E
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#define HV_X64_MSR_SINT15 0x4000009F
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/*
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* Synthetic Timer MSRs. Four timers per vcpu.
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*/
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#define HV_X64_MSR_STIMER0_CONFIG 0x400000B0
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#define HV_X64_MSR_STIMER0_COUNT 0x400000B1
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#define HV_X64_MSR_STIMER1_CONFIG 0x400000B2
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#define HV_X64_MSR_STIMER1_COUNT 0x400000B3
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#define HV_X64_MSR_STIMER2_CONFIG 0x400000B4
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#define HV_X64_MSR_STIMER2_COUNT 0x400000B5
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#define HV_X64_MSR_STIMER3_CONFIG 0x400000B6
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#define HV_X64_MSR_STIMER3_COUNT 0x400000B7
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#define HV_X64_MSR_HYPERCALL_ENABLE 0x00000001
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#define HV_X64_MSR_HYPERCALL_PAGE_ADDRESS_SHIFT 12
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@ -28,7 +28,9 @@
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#include <linux/hyperv.h>
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#include <linux/version.h>
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#include <linux/interrupt.h>
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#include <linux/clockchips.h>
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#include <asm/hyperv.h>
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#include <asm/mshyperv.h>
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#include "hyperv_vmbus.h"
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/* The one and only */
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@ -37,6 +39,10 @@ struct hv_context hv_context = {
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.hypercall_page = NULL,
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};
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#define HV_TIMER_FREQUENCY (10 * 1000 * 1000) /* 100ns period */
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#define HV_MAX_MAX_DELTA_TICKS 0xffffffff
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#define HV_MIN_DELTA_TICKS 1
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/*
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* query_hypervisor_info - Get version info of the windows hypervisor
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*/
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@ -144,6 +150,8 @@ int hv_init(void)
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sizeof(int) * NR_CPUS);
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memset(hv_context.event_dpc, 0,
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sizeof(void *) * NR_CPUS);
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memset(hv_context.clk_evt, 0,
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sizeof(void *) * NR_CPUS);
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max_leaf = query_hypervisor_info();
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@ -258,10 +266,63 @@ u16 hv_signal_event(void *con_id)
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return status;
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}
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static int hv_ce_set_next_event(unsigned long delta,
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struct clock_event_device *evt)
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{
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cycle_t current_tick;
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WARN_ON(evt->mode != CLOCK_EVT_MODE_ONESHOT);
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rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
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current_tick += delta;
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wrmsrl(HV_X64_MSR_STIMER0_COUNT, current_tick);
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return 0;
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}
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static void hv_ce_setmode(enum clock_event_mode mode,
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struct clock_event_device *evt)
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{
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union hv_timer_config timer_cfg;
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switch (mode) {
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case CLOCK_EVT_MODE_PERIODIC:
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/* unsupported */
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break;
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case CLOCK_EVT_MODE_ONESHOT:
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timer_cfg.enable = 1;
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timer_cfg.auto_enable = 1;
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timer_cfg.sintx = VMBUS_MESSAGE_SINT;
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wrmsrl(HV_X64_MSR_STIMER0_CONFIG, timer_cfg.as_uint64);
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break;
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case CLOCK_EVT_MODE_UNUSED:
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case CLOCK_EVT_MODE_SHUTDOWN:
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wrmsrl(HV_X64_MSR_STIMER0_COUNT, 0);
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wrmsrl(HV_X64_MSR_STIMER0_CONFIG, 0);
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break;
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case CLOCK_EVT_MODE_RESUME:
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break;
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}
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}
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static void hv_init_clockevent_device(struct clock_event_device *dev, int cpu)
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{
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dev->name = "Hyper-V clockevent";
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dev->features = CLOCK_EVT_FEAT_ONESHOT;
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dev->cpumask = cpumask_of(cpu);
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dev->rating = 1000;
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dev->owner = THIS_MODULE;
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dev->set_mode = hv_ce_setmode;
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dev->set_next_event = hv_ce_set_next_event;
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}
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int hv_synic_alloc(void)
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{
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size_t size = sizeof(struct tasklet_struct);
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size_t ced_size = sizeof(struct clock_event_device);
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int cpu;
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for_each_online_cpu(cpu) {
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@ -272,6 +333,13 @@ int hv_synic_alloc(void)
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}
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tasklet_init(hv_context.event_dpc[cpu], vmbus_on_event, cpu);
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hv_context.clk_evt[cpu] = kzalloc(ced_size, GFP_ATOMIC);
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if (hv_context.clk_evt[cpu] == NULL) {
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pr_err("Unable to allocate clock event device\n");
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goto err;
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}
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hv_init_clockevent_device(hv_context.clk_evt[cpu], cpu);
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hv_context.synic_message_page[cpu] =
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(void *)get_zeroed_page(GFP_ATOMIC);
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@ -305,6 +373,7 @@ int hv_synic_alloc(void)
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static void hv_synic_free_cpu(int cpu)
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{
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kfree(hv_context.event_dpc[cpu]);
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kfree(hv_context.clk_evt[cpu]);
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if (hv_context.synic_event_page[cpu])
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free_page((unsigned long)hv_context.synic_event_page[cpu]);
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if (hv_context.synic_message_page[cpu])
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@ -388,6 +457,15 @@ void hv_synic_init(void *arg)
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hv_context.vp_index[cpu] = (u32)vp_index;
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INIT_LIST_HEAD(&hv_context.percpu_list[cpu]);
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/*
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* Register the per-cpu clockevent source.
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*/
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if (ms_hyperv.features & HV_X64_MSR_SYNTIMER_AVAILABLE)
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clockevents_config_and_register(hv_context.clk_evt[cpu],
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HV_TIMER_FREQUENCY,
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HV_MIN_DELTA_TICKS,
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HV_MAX_MAX_DELTA_TICKS);
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return;
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}
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@ -178,6 +178,23 @@ struct hv_message_header {
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};
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};
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/*
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* Timer configuration register.
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*/
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union hv_timer_config {
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u64 as_uint64;
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struct {
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u64 enable:1;
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u64 periodic:1;
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u64 lazy:1;
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u64 auto_enable:1;
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u64 reserved_z0:12;
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u64 sintx:4;
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u64 reserved_z1:44;
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};
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};
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/* Define timer message payload structure. */
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struct hv_timer_message_payload {
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u32 timer_index;
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@ -519,6 +536,10 @@ struct hv_context {
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* buffer to post messages to the host.
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*/
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void *post_msg_page[NR_CPUS];
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/*
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* Support PV clockevent device.
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*/
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struct clock_event_device *clk_evt[NR_CPUS];
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};
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extern struct hv_context hv_context;
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@ -32,6 +32,7 @@
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#include <linux/completion.h>
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#include <linux/hyperv.h>
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#include <linux/kernel_stat.h>
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#include <linux/clockchips.h>
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#include <asm/hyperv.h>
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#include <asm/hypervisor.h>
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#include <asm/mshyperv.h>
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@ -578,6 +579,34 @@ static void vmbus_onmessage_work(struct work_struct *work)
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kfree(ctx);
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}
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void hv_process_timer_expiration(struct hv_message *msg, int cpu)
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{
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struct clock_event_device *dev = hv_context.clk_evt[cpu];
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if (dev->event_handler)
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dev->event_handler(dev);
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msg->header.message_type = HVMSG_NONE;
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/*
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* Make sure the write to MessageType (ie set to
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* HVMSG_NONE) happens before we read the
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* MessagePending and EOMing. Otherwise, the EOMing
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* will not deliver any more messages since there is
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* no empty slot
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*/
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mb();
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if (msg->header.message_flags.msg_pending) {
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/*
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* This will cause message queue rescan to
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* possibly deliver another msg from the
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* hypervisor
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*/
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wrmsrl(HV_X64_MSR_EOM, 0);
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}
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}
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static void vmbus_on_msg_dpc(unsigned long data)
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{
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int cpu = smp_processor_id();
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@ -667,8 +696,12 @@ static void vmbus_isr(void)
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msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
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/* Check if there are actual msgs to be processed */
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if (msg->header.message_type != HVMSG_NONE)
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tasklet_schedule(&msg_dpc);
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if (msg->header.message_type != HVMSG_NONE) {
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if (msg->header.message_type == HVMSG_TIMER_EXPIRED)
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hv_process_timer_expiration(msg, cpu);
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else
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tasklet_schedule(&msg_dpc);
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}
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}
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/*
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