diff options
Diffstat (limited to 'drivers/hv/hv.c')
| -rw-r--r-- | drivers/hv/hv.c | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c index c641faf..6341be8 100644 --- a/drivers/hv/hv.c +++ b/drivers/hv/hv.c @@ -133,6 +133,56 @@ static u64 do_hypercall(u64 control, void *input, void *output) #endif /* !x86_64 */ } +#ifdef CONFIG_X86_64 +static cycle_t read_hv_clock_tsc(struct clocksource *arg) +{ + cycle_t current_tick; + struct ms_hyperv_tsc_page *tsc_pg = hv_context.tsc_page; + + if (tsc_pg->tsc_sequence != -1) { + /* + * Use the tsc page to compute the value. + */ + + while (1) { + cycle_t tmp; + u32 sequence = tsc_pg->tsc_sequence; + u64 cur_tsc; + u64 scale = tsc_pg->tsc_scale; + s64 offset = tsc_pg->tsc_offset; + + rdtscll(cur_tsc); + /* current_tick = ((cur_tsc *scale) >> 64) + offset */ + asm("mulq %3" + : "=d" (current_tick), "=a" (tmp) + : "a" (cur_tsc), "r" (scale)); + + current_tick += offset; + if (tsc_pg->tsc_sequence == sequence) + return current_tick; + + if (tsc_pg->tsc_sequence != -1) + continue; + /* + * Fallback using MSR method. + */ + break; + } + } + rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick); + return current_tick; +} + +static struct clocksource hyperv_cs_tsc = { + .name = "hyperv_clocksource_tsc_page", + .rating = 425, + .read = read_hv_clock_tsc, + .mask = CLOCKSOURCE_MASK(64), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; +#endif + + /* * hv_init - Main initialization routine. * @@ -142,7 +192,9 @@ int hv_init(void) { int max_leaf; union hv_x64_msr_hypercall_contents hypercall_msr; + union hv_x64_msr_hypercall_contents tsc_msr; void *virtaddr = NULL; + void *va_tsc = NULL; memset(hv_context.synic_event_page, 0, sizeof(void *) * NR_CPUS); memset(hv_context.synic_message_page, 0, @@ -186,6 +238,22 @@ int hv_init(void) hv_context.hypercall_page = virtaddr; +#ifdef CONFIG_X86_64 + if (ms_hyperv.features & HV_X64_MSR_REFERENCE_TSC_AVAILABLE) { + va_tsc = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL); + if (!va_tsc) + goto cleanup; + hv_context.tsc_page = va_tsc; + + rdmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64); + + tsc_msr.enable = 1; + tsc_msr.guest_physical_address = vmalloc_to_pfn(va_tsc); + + wrmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64); + clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100); + } +#endif return 0; cleanup: @@ -219,6 +287,21 @@ void hv_cleanup(void) vfree(hv_context.hypercall_page); hv_context.hypercall_page = NULL; } + +#ifdef CONFIG_X86_64 + /* + * Cleanup the TSC page based CS. + */ + if (ms_hyperv.features & HV_X64_MSR_REFERENCE_TSC_AVAILABLE) { + clocksource_change_rating(&hyperv_cs_tsc, 10); + clocksource_unregister(&hyperv_cs_tsc); + + hypercall_msr.as_uint64 = 0; + wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64); + vfree(hv_context.tsc_page); + hv_context.tsc_page = NULL; + } +#endif } /* |
