Drivers: hv: vmbus: Implement a clocksource based on the TSC page (ca9357bd) · Commits · 戴 / test

arch/x86/include/uapi/asm/hyperv.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -27,6 +27,8 @@
		#define HV_X64_MSR_VP_RUNTIME_AVAILABLE (1 << 0)
		/* Partition Reference Counter (HV_X64_MSR_TIME_REF_COUNT) available*/
		#define HV_X64_MSR_TIME_REF_COUNT_AVAILABLE (1 << 1)
		/* Partition reference TSC MSR is available */
		#define HV_X64_MSR_REFERENCE_TSC_AVAILABLE (1 << 9)

		/* A partition's reference time stamp counter (TSC) page */
		#define HV_X64_MSR_REFERENCE_TSC 0x40000021

drivers/hv/hv.c

+83 −0

Original line number	Diff line number	Diff line
		@@ -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
		}

		/*

drivers/hv/hyperv_vmbus.h

+9 −0

Original line number	Diff line number	Diff line
		@@ -517,6 +517,7 @@ struct hv_context {
		u64 guestid;

		void *hypercall_page;
		void *tsc_page;

		bool synic_initialized;

		@@ -560,6 +561,14 @@ 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;

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