> -----Original Message----- > From: K. Y. Srinivasan [mailto:kys@xxxxxxxxxxxxx] > Sent: Thursday, December 4, 2014 6:07 PM > To: gregkh@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > devel@xxxxxxxxxxxxxxxxxxxxxx; olaf@xxxxxxxxx; apw@xxxxxxxxxxxxx; > jasowang@xxxxxxxxxx > Cc: KY Srinivasan > Subject: [PATCH 1/1] Drivers: hv: vmbus: Implement a clockevent device > > > Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx> > --- > arch/x86/include/uapi/asm/hyperv.h | 11 +++++ > drivers/hv/hv.c | 78 > ++++++++++++++++++++++++++++++++++++ > drivers/hv/hyperv_vmbus.h | 21 ++++++++++ > drivers/hv/vmbus_drv.c | 40 +++++++++++++++++- > 4 files changed, 148 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/include/uapi/asm/hyperv.h > b/arch/x86/include/uapi/asm/hyperv.h > index 462efe7..90c458e 100644 > --- a/arch/x86/include/uapi/asm/hyperv.h > +++ b/arch/x86/include/uapi/asm/hyperv.h > @@ -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 > diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c index 3e4235c..e2749c0 100644 > --- a/drivers/hv/hv.c > +++ b/drivers/hv/hv.c > @@ -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 @@ err: > 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; > } > > diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h index > c386d8d..44b1c94 100644 > --- a/drivers/hv/hyperv_vmbus.h > +++ b/drivers/hv/hyperv_vmbus.h > @@ -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; > diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index > 4d6b269..9e57c07 100644 > --- a/drivers/hv/vmbus_drv.c > +++ b/drivers/hv/vmbus_drv.c > @@ -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 +579,37 @@ 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 (msg->header.message_type == HVMSG_NONE) > + return; > + > + 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 +699,12 @@ 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); > + } > } > > /* > -- > 1.7.4.1 Greg, Please ignore this patch. I will add the commit message and resend it. K. 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