arch/x86/include/asm/mshyperv.h - third_party/linux - Git at Google

 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _ASM_X86_MSHYPER_H
 #define _ASM_X86_MSHYPER_H

 #include <linux/types.h>
 #include <linux/atomic.h>
 #include <linux/nmi.h>
 #include <asm/io.h>
 #include <asm/hyperv-tlfs.h>
 #include <asm/nospec-branch.h>

 #define VP_INVAL	U32_MAX

 struct ms_hyperv_info {
 	u32 features;
 	u32 misc_features;
 	u32 hints;
 	u32 nested_features;
 	u32 max_vp_index;
 	u32 max_lp_index;
 };

 extern struct ms_hyperv_info ms_hyperv;

 /*
  * Generate the guest ID.
  */

 static inline  __u64 generate_guest_id(__u64 d_info1, __u64 kernel_version,
 				       __u64 d_info2)
 {
 	__u64 guest_id = 0;

 	guest_id = (((__u64)HV_LINUX_VENDOR_ID) << 48);
 	guest_id |= (d_info1 << 48);
 	guest_id |= (kernel_version << 16);
 	guest_id |= d_info2;

 	return guest_id;
 }


 /* Free the message slot and signal end-of-message if required */
 static inline void vmbus_signal_eom(struct hv_message *msg, u32 old_msg_type)
 {
 	/*
 	 * On crash we're reading some other CPU's message page and we need
 	 * to be careful: this other CPU may already had cleared the header
 	 * and the host may already had delivered some other message there.
 	 * In case we blindly write msg->header.message_type we're going
 	 * to lose it. We can still lose a message of the same type but
 	 * we count on the fact that there can only be one
 	 * CHANNELMSG_UNLOAD_RESPONSE and we don't care about other messages
 	 * on crash.
 	 */
 	if (cmpxchg(&msg->header.message_type, old_msg_type,
 		    HVMSG_NONE) != old_msg_type)
 		return;

 	/*
 	 * 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);
 	}
 }

 #define hv_init_timer(timer, tick) wrmsrl(timer, tick)
 #define hv_init_timer_config(config, val) wrmsrl(config, val)

 #define hv_get_simp(val) rdmsrl(HV_X64_MSR_SIMP, val)
 #define hv_set_simp(val) wrmsrl(HV_X64_MSR_SIMP, val)

 #define hv_get_siefp(val) rdmsrl(HV_X64_MSR_SIEFP, val)
 #define hv_set_siefp(val) wrmsrl(HV_X64_MSR_SIEFP, val)

 #define hv_get_synic_state(val) rdmsrl(HV_X64_MSR_SCONTROL, val)
 #define hv_set_synic_state(val) wrmsrl(HV_X64_MSR_SCONTROL, val)

 #define hv_get_vp_index(index) rdmsrl(HV_X64_MSR_VP_INDEX, index)

 #define hv_get_synint_state(int_num, val) rdmsrl(int_num, val)
 #define hv_set_synint_state(int_num, val) wrmsrl(int_num, val)

 void hyperv_callback_vector(void);
 void hyperv_reenlightenment_vector(void);
 #ifdef CONFIG_TRACING
 #define trace_hyperv_callback_vector hyperv_callback_vector
 #endif
 void hyperv_vector_handler(struct pt_regs *regs);
 void hv_setup_vmbus_irq(void (*handler)(void));
 void hv_remove_vmbus_irq(void);

 void hv_setup_kexec_handler(void (*handler)(void));
 void hv_remove_kexec_handler(void);
 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs));
 void hv_remove_crash_handler(void);

 /*
  * Routines for stimer0 Direct Mode handling.
  * On x86/x64, there are no percpu actions to take.
  */
 void hv_stimer0_vector_handler(struct pt_regs *regs);
 void hv_stimer0_callback_vector(void);
 int hv_setup_stimer0_irq(int *irq, int *vector, void (*handler)(void));
 void hv_remove_stimer0_irq(int irq);

 static inline void hv_enable_stimer0_percpu_irq(int irq) {}
 static inline void hv_disable_stimer0_percpu_irq(int irq) {}


 #if IS_ENABLED(CONFIG_HYPERV)
 extern struct clocksource *hyperv_cs;
 extern void *hv_hypercall_pg;
 extern void  __percpu  **hyperv_pcpu_input_arg;

 static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
 {
 	u64 input_address = input ? virt_to_phys(input) : 0;
 	u64 output_address = output ? virt_to_phys(output) : 0;
 	u64 hv_status;

 #ifdef CONFIG_X86_64
 	if (!hv_hypercall_pg)
 		return U64_MAX;

 	__asm__ __volatile__("mov %4, %%r8\n"
 			     CALL_NOSPEC
 			     : "=a" (hv_status), ASM_CALL_CONSTRAINT,
 			       "+c" (control), "+d" (input_address)
 			     :  "r" (output_address),
 				THUNK_TARGET(hv_hypercall_pg)
 			     : "cc", "memory", "r8", "r9", "r10", "r11");
 #else
 	u32 input_address_hi = upper_32_bits(input_address);
 	u32 input_address_lo = lower_32_bits(input_address);
 	u32 output_address_hi = upper_32_bits(output_address);
 	u32 output_address_lo = lower_32_bits(output_address);

 	if (!hv_hypercall_pg)
 		return U64_MAX;

 	__asm__ __volatile__(CALL_NOSPEC
 			     : "=A" (hv_status),
 			       "+c" (input_address_lo), ASM_CALL_CONSTRAINT
 			     : "A" (control),
 			       "b" (input_address_hi),
 			       "D"(output_address_hi), "S"(output_address_lo),
 			       THUNK_TARGET(hv_hypercall_pg)
 			     : "cc", "memory");
 #endif /* !x86_64 */
 	return hv_status;
 }

 /* Fast hypercall with 8 bytes of input and no output */
 static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1)
 {
 	u64 hv_status, control = (u64)code | HV_HYPERCALL_FAST_BIT;

 #ifdef CONFIG_X86_64
 	{
 		__asm__ __volatile__(CALL_NOSPEC
 				     : "=a" (hv_status), ASM_CALL_CONSTRAINT,
 				       "+c" (control), "+d" (input1)
 				     : THUNK_TARGET(hv_hypercall_pg)
 				     : "cc", "r8", "r9", "r10", "r11");
 	}
 #else
 	{
 		u32 input1_hi = upper_32_bits(input1);
 		u32 input1_lo = lower_32_bits(input1);

 		__asm__ __volatile__ (CALL_NOSPEC
 				      : "=A"(hv_status),
 					"+c"(input1_lo),
 					ASM_CALL_CONSTRAINT
 				      :	"A" (control),
 					"b" (input1_hi),
 					THUNK_TARGET(hv_hypercall_pg)
 				      : "cc", "edi", "esi");
 	}
 #endif
 		return hv_status;
 }

 /*
  * Rep hypercalls. Callers of this functions are supposed to ensure that
  * rep_count and varhead_size comply with Hyper-V hypercall definition.
  */
 static inline u64 hv_do_rep_hypercall(u16 code, u16 rep_count, u16 varhead_size,
 				      void *input, void *output)
 {
 	u64 control = code;
 	u64 status;
 	u16 rep_comp;

 	control |= (u64)varhead_size << HV_HYPERCALL_VARHEAD_OFFSET;
 	control |= (u64)rep_count << HV_HYPERCALL_REP_COMP_OFFSET;

 	do {
 		status = hv_do_hypercall(control, input, output);
 		if ((status & HV_HYPERCALL_RESULT_MASK) != HV_STATUS_SUCCESS)
 			return status;

 		/* Bits 32-43 of status have 'Reps completed' data. */
 		rep_comp = (status & HV_HYPERCALL_REP_COMP_MASK) >>
 			HV_HYPERCALL_REP_COMP_OFFSET;

 		control &= ~HV_HYPERCALL_REP_START_MASK;
 		control |= (u64)rep_comp << HV_HYPERCALL_REP_START_OFFSET;

 		touch_nmi_watchdog();
 	} while (rep_comp < rep_count);

 	return status;
 }

 /*
  * Hypervisor's notion of virtual processor ID is different from
  * Linux' notion of CPU ID. This information can only be retrieved
  * in the context of the calling CPU. Setup a map for easy access
  * to this information.
  */
 extern u32 *hv_vp_index;
 extern u32 hv_max_vp_index;
 extern struct hv_vp_assist_page **hv_vp_assist_page;

 static inline struct hv_vp_assist_page *hv_get_vp_assist_page(unsigned int cpu)
 {
 	if (!hv_vp_assist_page)
 		return NULL;

 	return hv_vp_assist_page[cpu];
 }

 /**
  * hv_cpu_number_to_vp_number() - Map CPU to VP.
  * @cpu_number: CPU number in Linux terms
  *
  * This function returns the mapping between the Linux processor
  * number and the hypervisor's virtual processor number, useful
  * in making hypercalls and such that talk about specific
  * processors.
  *
  * Return: Virtual processor number in Hyper-V terms
  */
 static inline int hv_cpu_number_to_vp_number(int cpu_number)
 {
 	return hv_vp_index[cpu_number];
 }

 static inline int cpumask_to_vpset(struct hv_vpset *vpset,
 				    const struct cpumask *cpus)
 {
 	int cpu, vcpu, vcpu_bank, vcpu_offset, nr_bank = 1;

 	/* valid_bank_mask can represent up to 64 banks */
 	if (hv_max_vp_index / 64 >= 64)
 		return 0;

 	/*
 	 * Clear all banks up to the maximum possible bank as hv_tlb_flush_ex
 	 * structs are not cleared between calls, we risk flushing unneeded
 	 * vCPUs otherwise.
 	 */
 	for (vcpu_bank = 0; vcpu_bank <= hv_max_vp_index / 64; vcpu_bank++)
 		vpset->bank_contents[vcpu_bank] = 0;

 	/*
 	 * Some banks may end up being empty but this is acceptable.
 	 */
 	for_each_cpu(cpu, cpus) {
 		vcpu = hv_cpu_number_to_vp_number(cpu);
 		if (vcpu == VP_INVAL)
 			return -1;
 		vcpu_bank = vcpu / 64;
 		vcpu_offset = vcpu % 64;
 		__set_bit(vcpu_offset, (unsigned long *)
 			  &vpset->bank_contents[vcpu_bank]);
 		if (vcpu_bank >= nr_bank)
 			nr_bank = vcpu_bank + 1;
 	}
 	vpset->valid_bank_mask = GENMASK_ULL(nr_bank - 1, 0);
 	return nr_bank;
 }

 void __init hyperv_init(void);
 void hyperv_setup_mmu_ops(void);
 void hyperv_report_panic(struct pt_regs *regs, long err);
 bool hv_is_hyperv_initialized(void);
 void hyperv_cleanup(void);

 void hyperv_reenlightenment_intr(struct pt_regs *regs);
 void set_hv_tscchange_cb(void (*cb)(void));
 void clear_hv_tscchange_cb(void);
 void hyperv_stop_tsc_emulation(void);

 #ifdef CONFIG_X86_64
 void hv_apic_init(void);
 #else
 static inline void hv_apic_init(void) {}
 #endif

 #else /* CONFIG_HYPERV */
 static inline void hyperv_init(void) {}
 static inline bool hv_is_hyperv_initialized(void) { return false; }
 static inline void hyperv_cleanup(void) {}
 static inline void hyperv_setup_mmu_ops(void) {}
 static inline void set_hv_tscchange_cb(void (*cb)(void)) {}
 static inline void clear_hv_tscchange_cb(void) {}
 static inline void hyperv_stop_tsc_emulation(void) {};
 static inline struct hv_vp_assist_page *hv_get_vp_assist_page(unsigned int cpu)
 {
 	return NULL;
 }
 #endif /* CONFIG_HYPERV */

 #ifdef CONFIG_HYPERV_TSCPAGE
 struct ms_hyperv_tsc_page *hv_get_tsc_page(void);
 static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg,
 				       u64 *cur_tsc)
 {
 	u64 scale, offset;
 	u32 sequence;

 	/*
 	 * The protocol for reading Hyper-V TSC page is specified in Hypervisor
 	 * Top-Level Functional Specification ver. 3.0 and above. To get the
 	 * reference time we must do the following:
 	 * - READ ReferenceTscSequence
 	 *   A special '0' value indicates the time source is unreliable and we
 	 *   need to use something else. The currently published specification
 	 *   versions (up to 4.0b) contain a mistake and wrongly claim '-1'
 	 *   instead of '0' as the special value, see commit c35b82ef0294.
 	 * - ReferenceTime =
 	 *        ((RDTSC() * ReferenceTscScale) >> 64) + ReferenceTscOffset
 	 * - READ ReferenceTscSequence again. In case its value has changed
 	 *   since our first reading we need to discard ReferenceTime and repeat
 	 *   the whole sequence as the hypervisor was updating the page in
 	 *   between.
 	 */
 	do {
 		sequence = READ_ONCE(tsc_pg->tsc_sequence);
 		if (!sequence)
 			return U64_MAX;
 		/*
 		 * Make sure we read sequence before we read other values from
 		 * TSC page.
 		 */
 		smp_rmb();

 		scale = READ_ONCE(tsc_pg->tsc_scale);
 		offset = READ_ONCE(tsc_pg->tsc_offset);
 		*cur_tsc = rdtsc_ordered();

 		/*
 		 * Make sure we read sequence after we read all other values
 		 * from TSC page.
 		 */
 		smp_rmb();

 	} while (READ_ONCE(tsc_pg->tsc_sequence) != sequence);

 	return mul_u64_u64_shr(*cur_tsc, scale, 64) + offset;
 }

 static inline u64 hv_read_tsc_page(const struct ms_hyperv_tsc_page *tsc_pg)
 {
 	u64 cur_tsc;

 	return hv_read_tsc_page_tsc(tsc_pg, &cur_tsc);
 }

 #else
 static inline struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
 {
 	return NULL;
 }

 static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg,
 				       u64 *cur_tsc)
 {
 	BUG();
 	return U64_MAX;
 }
 #endif
 #endif
	/* SPDX-License-Identifier: GPL-2.0 */
	#ifndef _ASM_X86_MSHYPER_H
	#define _ASM_X86_MSHYPER_H

	#include <linux/types.h>
	#include <linux/atomic.h>
	#include <linux/nmi.h>
	#include <asm/io.h>
	#include <asm/hyperv-tlfs.h>
	#include <asm/nospec-branch.h>

	#define VP_INVAL U32_MAX

	struct ms_hyperv_info {
	u32 features;
	u32 misc_features;
	u32 hints;
	u32 nested_features;
	u32 max_vp_index;
	u32 max_lp_index;
	};

	extern struct ms_hyperv_info ms_hyperv;

	/*
	* Generate the guest ID.
	*/

	static inline __u64 generate_guest_id(__u64 d_info1, __u64 kernel_version,
	__u64 d_info2)
	{
	__u64 guest_id = 0;

	guest_id = (((__u64)HV_LINUX_VENDOR_ID) << 48);
	guest_id \|= (d_info1 << 48);
	guest_id \|= (kernel_version << 16);
	guest_id \|= d_info2;

	return guest_id;
	}


	/* Free the message slot and signal end-of-message if required */
	static inline void vmbus_signal_eom(struct hv_message *msg, u32 old_msg_type)
	{
	/*
	* On crash we're reading some other CPU's message page and we need
	* to be careful: this other CPU may already had cleared the header
	* and the host may already had delivered some other message there.
	* In case we blindly write msg->header.message_type we're going
	* to lose it. We can still lose a message of the same type but
	* we count on the fact that there can only be one
	* CHANNELMSG_UNLOAD_RESPONSE and we don't care about other messages
	* on crash.
	*/
	if (cmpxchg(&msg->header.message_type, old_msg_type,
	HVMSG_NONE) != old_msg_type)
	return;

	/*
	* 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);
	}
	}

	#define hv_init_timer(timer, tick) wrmsrl(timer, tick)
	#define hv_init_timer_config(config, val) wrmsrl(config, val)

	#define hv_get_simp(val) rdmsrl(HV_X64_MSR_SIMP, val)
	#define hv_set_simp(val) wrmsrl(HV_X64_MSR_SIMP, val)

	#define hv_get_siefp(val) rdmsrl(HV_X64_MSR_SIEFP, val)
	#define hv_set_siefp(val) wrmsrl(HV_X64_MSR_SIEFP, val)

	#define hv_get_synic_state(val) rdmsrl(HV_X64_MSR_SCONTROL, val)
	#define hv_set_synic_state(val) wrmsrl(HV_X64_MSR_SCONTROL, val)

	#define hv_get_vp_index(index) rdmsrl(HV_X64_MSR_VP_INDEX, index)

	#define hv_get_synint_state(int_num, val) rdmsrl(int_num, val)
	#define hv_set_synint_state(int_num, val) wrmsrl(int_num, val)

	void hyperv_callback_vector(void);
	void hyperv_reenlightenment_vector(void);
	#ifdef CONFIG_TRACING
	#define trace_hyperv_callback_vector hyperv_callback_vector
	#endif
	void hyperv_vector_handler(struct pt_regs *regs);
	void hv_setup_vmbus_irq(void (*handler)(void));
	void hv_remove_vmbus_irq(void);

	void hv_setup_kexec_handler(void (*handler)(void));
	void hv_remove_kexec_handler(void);
	void hv_setup_crash_handler(void (handler)(struct pt_regs regs));
	void hv_remove_crash_handler(void);

	/*
	* Routines for stimer0 Direct Mode handling.
	* On x86/x64, there are no percpu actions to take.
	*/
	void hv_stimer0_vector_handler(struct pt_regs *regs);
	void hv_stimer0_callback_vector(void);
	int hv_setup_stimer0_irq(int irq, int vector, void (*handler)(void));
	void hv_remove_stimer0_irq(int irq);

	static inline void hv_enable_stimer0_percpu_irq(int irq) {}
	static inline void hv_disable_stimer0_percpu_irq(int irq) {}


	#if IS_ENABLED(CONFIG_HYPERV)
	extern struct clocksource *hyperv_cs;
	extern void *hv_hypercall_pg;
	extern void __percpu **hyperv_pcpu_input_arg;

	static inline u64 hv_do_hypercall(u64 control, void input, void output)
	{
	u64 input_address = input ? virt_to_phys(input) : 0;
	u64 output_address = output ? virt_to_phys(output) : 0;
	u64 hv_status;

	#ifdef CONFIG_X86_64
	if (!hv_hypercall_pg)
	return U64_MAX;

	__asm__ __volatile__("mov %4, %%r8\n"
	CALL_NOSPEC
	: "=a" (hv_status), ASM_CALL_CONSTRAINT,
	"+c" (control), "+d" (input_address)
	: "r" (output_address),
	THUNK_TARGET(hv_hypercall_pg)
	: "cc", "memory", "r8", "r9", "r10", "r11");
	#else
	u32 input_address_hi = upper_32_bits(input_address);
	u32 input_address_lo = lower_32_bits(input_address);
	u32 output_address_hi = upper_32_bits(output_address);
	u32 output_address_lo = lower_32_bits(output_address);

	if (!hv_hypercall_pg)
	return U64_MAX;

	__asm__ __volatile__(CALL_NOSPEC
	: "=A" (hv_status),
	"+c" (input_address_lo), ASM_CALL_CONSTRAINT
	: "A" (control),
	"b" (input_address_hi),
	"D"(output_address_hi), "S"(output_address_lo),
	THUNK_TARGET(hv_hypercall_pg)
	: "cc", "memory");
	#endif /* !x86_64 */
	return hv_status;
	}

	/* Fast hypercall with 8 bytes of input and no output */
	static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1)
	{
	u64 hv_status, control = (u64)code \| HV_HYPERCALL_FAST_BIT;

	#ifdef CONFIG_X86_64
	{
	__asm__ __volatile__(CALL_NOSPEC
	: "=a" (hv_status), ASM_CALL_CONSTRAINT,
	"+c" (control), "+d" (input1)
	: THUNK_TARGET(hv_hypercall_pg)
	: "cc", "r8", "r9", "r10", "r11");
	}
	#else
	{
	u32 input1_hi = upper_32_bits(input1);
	u32 input1_lo = lower_32_bits(input1);

	__asm__ __volatile__ (CALL_NOSPEC
	: "=A"(hv_status),
	"+c"(input1_lo),
	ASM_CALL_CONSTRAINT
	: "A" (control),
	"b" (input1_hi),
	THUNK_TARGET(hv_hypercall_pg)
	: "cc", "edi", "esi");
	}
	#endif
	return hv_status;
	}

	/*
	* Rep hypercalls. Callers of this functions are supposed to ensure that
	* rep_count and varhead_size comply with Hyper-V hypercall definition.
	*/
	static inline u64 hv_do_rep_hypercall(u16 code, u16 rep_count, u16 varhead_size,
	void input, void output)
	{
	u64 control = code;
	u64 status;
	u16 rep_comp;

	control \|= (u64)varhead_size << HV_HYPERCALL_VARHEAD_OFFSET;
	control \|= (u64)rep_count << HV_HYPERCALL_REP_COMP_OFFSET;

	do {
	status = hv_do_hypercall(control, input, output);
	if ((status & HV_HYPERCALL_RESULT_MASK) != HV_STATUS_SUCCESS)
	return status;

	/* Bits 32-43 of status have 'Reps completed' data. */
	rep_comp = (status & HV_HYPERCALL_REP_COMP_MASK) >>
	HV_HYPERCALL_REP_COMP_OFFSET;

	control &= ~HV_HYPERCALL_REP_START_MASK;
	control \|= (u64)rep_comp << HV_HYPERCALL_REP_START_OFFSET;

	touch_nmi_watchdog();
	} while (rep_comp < rep_count);

	return status;
	}

	/*
	* Hypervisor's notion of virtual processor ID is different from
	* Linux' notion of CPU ID. This information can only be retrieved
	* in the context of the calling CPU. Setup a map for easy access
	* to this information.
	*/
	extern u32 *hv_vp_index;
	extern u32 hv_max_vp_index;
	extern struct hv_vp_assist_page **hv_vp_assist_page;

	static inline struct hv_vp_assist_page *hv_get_vp_assist_page(unsigned int cpu)
	{
	if (!hv_vp_assist_page)
	return NULL;

	return hv_vp_assist_page[cpu];
	}

	/**
	* hv_cpu_number_to_vp_number() - Map CPU to VP.
	* @cpu_number: CPU number in Linux terms
	*
	* This function returns the mapping between the Linux processor
	* number and the hypervisor's virtual processor number, useful
	* in making hypercalls and such that talk about specific
	* processors.
	*
	* Return: Virtual processor number in Hyper-V terms
	*/
	static inline int hv_cpu_number_to_vp_number(int cpu_number)
	{
	return hv_vp_index[cpu_number];
	}

	static inline int cpumask_to_vpset(struct hv_vpset *vpset,
	const struct cpumask *cpus)
	{
	int cpu, vcpu, vcpu_bank, vcpu_offset, nr_bank = 1;

	/* valid_bank_mask can represent up to 64 banks */
	if (hv_max_vp_index / 64 >= 64)
	return 0;

	/*
	* Clear all banks up to the maximum possible bank as hv_tlb_flush_ex
	* structs are not cleared between calls, we risk flushing unneeded
	* vCPUs otherwise.
	*/
	for (vcpu_bank = 0; vcpu_bank <= hv_max_vp_index / 64; vcpu_bank++)
	vpset->bank_contents[vcpu_bank] = 0;

	/*
	* Some banks may end up being empty but this is acceptable.
	*/
	for_each_cpu(cpu, cpus) {
	vcpu = hv_cpu_number_to_vp_number(cpu);
	if (vcpu == VP_INVAL)
	return -1;
	vcpu_bank = vcpu / 64;
	vcpu_offset = vcpu % 64;
	__set_bit(vcpu_offset, (unsigned long *)
	&vpset->bank_contents[vcpu_bank]);
	if (vcpu_bank >= nr_bank)
	nr_bank = vcpu_bank + 1;
	}
	vpset->valid_bank_mask = GENMASK_ULL(nr_bank - 1, 0);
	return nr_bank;
	}

	void __init hyperv_init(void);
	void hyperv_setup_mmu_ops(void);
	void hyperv_report_panic(struct pt_regs *regs, long err);
	bool hv_is_hyperv_initialized(void);
	void hyperv_cleanup(void);

	void hyperv_reenlightenment_intr(struct pt_regs *regs);
	void set_hv_tscchange_cb(void (*cb)(void));
	void clear_hv_tscchange_cb(void);
	void hyperv_stop_tsc_emulation(void);

	#ifdef CONFIG_X86_64
	void hv_apic_init(void);
	#else
	static inline void hv_apic_init(void) {}
	#endif

	#else /* CONFIG_HYPERV */
	static inline void hyperv_init(void) {}
	static inline bool hv_is_hyperv_initialized(void) { return false; }
	static inline void hyperv_cleanup(void) {}
	static inline void hyperv_setup_mmu_ops(void) {}
	static inline void set_hv_tscchange_cb(void (*cb)(void)) {}
	static inline void clear_hv_tscchange_cb(void) {}
	static inline void hyperv_stop_tsc_emulation(void) {};
	static inline struct hv_vp_assist_page *hv_get_vp_assist_page(unsigned int cpu)
	{
	return NULL;
	}
	#endif /* CONFIG_HYPERV */

	#ifdef CONFIG_HYPERV_TSCPAGE
	struct ms_hyperv_tsc_page *hv_get_tsc_page(void);
	static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg,
	u64 *cur_tsc)
	{
	u64 scale, offset;
	u32 sequence;

	/*
	* The protocol for reading Hyper-V TSC page is specified in Hypervisor
	* Top-Level Functional Specification ver. 3.0 and above. To get the
	* reference time we must do the following:
	* - READ ReferenceTscSequence
	* A special '0' value indicates the time source is unreliable and we
	* need to use something else. The currently published specification
	* versions (up to 4.0b) contain a mistake and wrongly claim '-1'
	* instead of '0' as the special value, see commit c35b82ef0294.
	* - ReferenceTime =
	* ((RDTSC() * ReferenceTscScale) >> 64) + ReferenceTscOffset
	* - READ ReferenceTscSequence again. In case its value has changed
	* since our first reading we need to discard ReferenceTime and repeat
	* the whole sequence as the hypervisor was updating the page in
	* between.
	*/
	do {
	sequence = READ_ONCE(tsc_pg->tsc_sequence);
	if (!sequence)
	return U64_MAX;
	/*
	* Make sure we read sequence before we read other values from
	* TSC page.
	*/
	smp_rmb();

	scale = READ_ONCE(tsc_pg->tsc_scale);
	offset = READ_ONCE(tsc_pg->tsc_offset);
	*cur_tsc = rdtsc_ordered();

	/*
	* Make sure we read sequence after we read all other values
	* from TSC page.
	*/
	smp_rmb();

	} while (READ_ONCE(tsc_pg->tsc_sequence) != sequence);

	return mul_u64_u64_shr(*cur_tsc, scale, 64) + offset;
	}

	static inline u64 hv_read_tsc_page(const struct ms_hyperv_tsc_page *tsc_pg)
	{
	u64 cur_tsc;

	return hv_read_tsc_page_tsc(tsc_pg, &cur_tsc);
	}

	#else
	static inline struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
	{
	return NULL;
	}

	static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg,
	u64 *cur_tsc)
	{
	BUG();
	return U64_MAX;
	}
	#endif
	#endif