diff options
Diffstat (limited to 'drivers/hv/hv.c')
| -rw-r--r-- | drivers/hv/hv.c | 59 |
1 files changed, 56 insertions, 3 deletions
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c index 31142b72f1b9..b1f6793acf4c 100644 --- a/drivers/hv/hv.c +++ b/drivers/hv/hv.c @@ -27,7 +27,7 @@ #include <linux/vmalloc.h> #include <linux/hyperv.h> #include <linux/version.h> -#include <linux/interrupt.h> +#include <linux/random.h> #include <linux/clockchips.h> #include <asm/hyperv.h> #include <asm/mshyperv.h> @@ -38,6 +38,17 @@ struct hv_context hv_context = { .synic_initialized = false, }; +/* + * If false, we're using the old mechanism for stimer0 interrupts + * where it sends a VMbus message when it expires. The old + * mechanism is used when running on older versions of Hyper-V + * that don't support Direct Mode. While Hyper-V provides + * four stimer's per CPU, Linux uses only stimer0. + */ +static bool direct_mode_enabled; +static int stimer0_irq; +static int stimer0_vector; + #define HV_TIMER_FREQUENCY (10 * 1000 * 1000) /* 100ns period */ #define HV_MAX_MAX_DELTA_TICKS 0xffffffff #define HV_MIN_DELTA_TICKS 1 @@ -53,6 +64,8 @@ int hv_init(void) if (!hv_context.cpu_context) return -ENOMEM; + direct_mode_enabled = ms_hyperv.misc_features & + HV_X64_STIMER_DIRECT_MODE_AVAILABLE; return 0; } @@ -91,6 +104,21 @@ int hv_post_message(union hv_connection_id connection_id, return status & 0xFFFF; } +/* + * ISR for when stimer0 is operating in Direct Mode. Direct Mode + * does not use VMbus or any VMbus messages, so process here and not + * in the VMbus driver code. + */ + +static void hv_stimer0_isr(void) +{ + struct hv_per_cpu_context *hv_cpu; + + hv_cpu = this_cpu_ptr(hv_context.cpu_context); + hv_cpu->clk_evt->event_handler(hv_cpu->clk_evt); + add_interrupt_randomness(stimer0_vector, 0); +} + static int hv_ce_set_next_event(unsigned long delta, struct clock_event_device *evt) { @@ -108,6 +136,8 @@ static int hv_ce_shutdown(struct clock_event_device *evt) { hv_init_timer(HV_X64_MSR_STIMER0_COUNT, 0); hv_init_timer_config(HV_X64_MSR_STIMER0_CONFIG, 0); + if (direct_mode_enabled) + hv_disable_stimer0_percpu_irq(stimer0_irq); return 0; } @@ -116,11 +146,26 @@ static int hv_ce_set_oneshot(struct clock_event_device *evt) { union hv_timer_config timer_cfg; + timer_cfg.as_uint64 = 0; timer_cfg.enable = 1; timer_cfg.auto_enable = 1; - timer_cfg.sintx = VMBUS_MESSAGE_SINT; + if (direct_mode_enabled) { + /* + * When it expires, the timer will directly interrupt + * on the specified hardware vector/IRQ. + */ + timer_cfg.direct_mode = 1; + timer_cfg.apic_vector = stimer0_vector; + hv_enable_stimer0_percpu_irq(stimer0_irq); + } else { + /* + * When it expires, the timer will generate a VMbus message, + * to be handled by the normal VMbus interrupt handler. + */ + timer_cfg.direct_mode = 0; + timer_cfg.sintx = VMBUS_MESSAGE_SINT; + } hv_init_timer_config(HV_X64_MSR_STIMER0_CONFIG, timer_cfg.as_uint64); - return 0; } @@ -191,6 +236,11 @@ int hv_synic_alloc(void) INIT_LIST_HEAD(&hv_cpu->chan_list); } + if (direct_mode_enabled && + hv_setup_stimer0_irq(&stimer0_irq, &stimer0_vector, + hv_stimer0_isr)) + goto err; + return 0; err: return -ENOMEM; @@ -292,6 +342,9 @@ void hv_synic_clockevents_cleanup(void) if (!(ms_hyperv.features & HV_X64_MSR_SYNTIMER_AVAILABLE)) return; + if (direct_mode_enabled) + hv_remove_stimer0_irq(stimer0_irq); + for_each_present_cpu(cpu) { struct hv_per_cpu_context *hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu); |