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/* SPDX-License-Identifier: GPL-2.0 */
* Linux-specific definitions for managing interactions with Microsoft's
* Hyper-V hypervisor. The definitions in this file are architecture
* independent. See arch/<arch>/include/asm/mshyperv.h for definitions
* that are specific to architecture <arch>.
* Definitions that are specified in the Hyper-V Top Level Functional
* Spec (TLFS) should not go in this file, but should instead go in
* hyperv-tlfs.h.
* Copyright (C) 2019, Microsoft, Inc.
* Author : Michael Kelley <>
#include <linux/types.h>
#include <linux/atomic.h>
#include <linux/bitops.h>
#include <linux/cpumask.h>
#include <asm/ptrace.h>
#include <asm/hyperv-tlfs.h>
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;
extern u64 hv_do_hypercall(u64 control, void *inputaddr, void *outputaddr);
extern u64 hv_do_fast_hypercall8(u16 control, u64 input8);
/* Generate the guest OS identifier as described in the Hyper-V TLFS */
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)
* The cmxchg() above does an implicit memory barrier to
* ensure 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
if (msg->header.message_flags.msg_pending) {
* This will cause message queue rescan to
* possibly deliver another msg from the
* hypervisor
void hv_setup_vmbus_irq(void (*handler)(void));
void hv_remove_vmbus_irq(void);
void hv_enable_vmbus_irq(void);
void hv_disable_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);
* 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;
/* Sentinel value for an uninitialized entry in hv_vp_index array */
#define VP_INVAL U32_MAX
* 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 *)
if (vcpu_bank >= nr_bank)
nr_bank = vcpu_bank + 1;
vpset->valid_bank_mask = GENMASK_ULL(nr_bank - 1, 0);
return nr_bank;
void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die);
void hyperv_report_panic_msg(phys_addr_t pa, size_t size);
bool hv_is_hyperv_initialized(void);
void hyperv_cleanup(void);
void hv_setup_sched_clock(void *sched_clock);
#else /* CONFIG_HYPERV */
static inline bool hv_is_hyperv_initialized(void) { return false; }
static inline void hyperv_cleanup(void) {}
#endif /* CONFIG_HYPERV */
extern int hv_setup_stimer0_irq(int *irq, int *vector, void (*handler)(void));
extern void hv_remove_stimer0_irq(int irq);