> -----Original Message----- > From: Jason Wang [mailto:jasowang@xxxxxxxxxx] > Sent: Thursday, December 4, 2014 10:52 PM > To: KY Srinivasan > Cc: gregkh@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > devel@xxxxxxxxxxxxxxxxxxxxxx; olaf@xxxxxxxxx; apw@xxxxxxxxxxxxx; KY > Srinivasan > Subject: Re: [PATCH V2 1/1] Drivers: hv: vmbus: Implement a clockevent > device > > > > On Fri, Dec 5, 2014 at 10:18 AM, K. Y. Srinivasan <kys@xxxxxxxxxxxxx> > wrote: > > Implement a clockevent device based on the timer support available on > > Hyper-V. > > > > 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; > > Nitpick: caller has checked this. Yes indeed; I will fix it and resend. > > > > + > > + 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 > > Reviewed-by: Jason Wang <jasowang@xxxxxxxxxx> Thanks Jason. K. Y _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
