Consolidate the guest-side and kvm-side definitions for Hyper-V TSC reference page.
While at this, rewrite read_hv_clock_tsc using the existing helpers. Signed-off-by: Roman Kagan <rka...@virtuozzo.com> --- arch/x86/include/asm/kvm_host.h | 2 +- arch/x86/include/uapi/asm/hyperv.h | 4 +-- drivers/hv/hyperv_vmbus.h | 8 ------ arch/x86/kvm/hyperv.c | 4 +-- drivers/hv/hv.c | 54 +++++++++++++++----------------------- 5 files changed, 26 insertions(+), 46 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 2e25038..2b85f49 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -713,7 +713,7 @@ struct kvm_hv { u64 hv_crash_param[HV_X64_MSR_CRASH_PARAMS]; u64 hv_crash_ctl; - HV_REFERENCE_TSC_PAGE tsc_ref; + struct hv_ref_tsc_page tsc_ref; }; struct kvm_arch { diff --git a/arch/x86/include/uapi/asm/hyperv.h b/arch/x86/include/uapi/asm/hyperv.h index 9b1a918..6098ab5 100644 --- a/arch/x86/include/uapi/asm/hyperv.h +++ b/arch/x86/include/uapi/asm/hyperv.h @@ -252,12 +252,12 @@ #define HV_STATUS_INVALID_CONNECTION_ID 18 #define HV_STATUS_INSUFFICIENT_BUFFERS 19 -typedef struct _HV_REFERENCE_TSC_PAGE { +struct hv_ref_tsc_page { __u32 tsc_sequence; __u32 res1; __u64 tsc_scale; __s64 tsc_offset; -} HV_REFERENCE_TSC_PAGE, *PHV_REFERENCE_TSC_PAGE; +}; /* Define the number of synthetic interrupt sources. */ #define HV_SYNIC_SINT_COUNT (16) diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h index 0675b39..4516498 100644 --- a/drivers/hv/hyperv_vmbus.h +++ b/drivers/hv/hyperv_vmbus.h @@ -475,14 +475,6 @@ struct hv_context { extern struct hv_context hv_context; -struct ms_hyperv_tsc_page { - volatile u32 tsc_sequence; - u32 reserved1; - volatile u64 tsc_scale; - volatile s64 tsc_offset; - u64 reserved2[509]; -}; - struct hv_ring_buffer_debug_info { u32 current_interrupt_mask; u32 current_read_index; diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index 1572c35..c7db112 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -806,7 +806,7 @@ static int kvm_hv_msr_set_crash_data(struct kvm_vcpu *vcpu, * These two equivalencies are implemented in this function. */ static bool compute_tsc_page_parameters(struct pvclock_vcpu_time_info *hv_clock, - HV_REFERENCE_TSC_PAGE *tsc_ref) + struct hv_ref_tsc_page *tsc_ref) { u64 max_mul; @@ -847,7 +847,7 @@ void kvm_hv_setup_tsc_page(struct kvm *kvm, u64 gfn; BUILD_BUG_ON(sizeof(tsc_seq) != sizeof(hv->tsc_ref.tsc_sequence)); - BUILD_BUG_ON(offsetof(HV_REFERENCE_TSC_PAGE, tsc_sequence) != 0); + BUILD_BUG_ON(offsetof(struct hv_ref_tsc_page, tsc_sequence) != 0); if (!(hv->hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE)) return; diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c index 446802a..a7256ec 100644 --- a/drivers/hv/hv.c +++ b/drivers/hv/hv.c @@ -137,41 +137,29 @@ EXPORT_SYMBOL_GPL(hv_do_hypercall); #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; + struct hv_ref_tsc_page *tsc_pg = hv_context.tsc_page; + u32 sequence; + u64 scale; + s64 offset; + + do { + sequence = tsc_pg->tsc_sequence; + virt_rmb(); + + if (!sequence) { + /* fallback to MSR */ + cycle_t current_tick; + rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick); + return current_tick; + } - if (tsc_pg->tsc_sequence != 0) { - /* - * Use the tsc page to compute the value. - */ + scale = tsc_pg->tsc_scale; + offset = tsc_pg->tsc_offset; - 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 != 0) - continue; - /* - * Fallback using MSR method. - */ - break; - } - } - rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick); - return current_tick; + virt_rmb(); + } while (tsc_pg->tsc_sequence != sequence); + + return mul_u64_u64_shr(rdtsc_ordered(), scale, 64) + offset; } static struct clocksource hyperv_cs_tsc = { -- 2.9.3