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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 <linux/nmi.h>
#include <asm/ptrace.h>
#include <asm/hyperv-tlfs.h>
struct ms_hyperv_info {
u32 features;
u32 priv_high;
u32 misc_features;
u32 hints;
u32 nested_features;
u32 max_vp_index;
u32 max_lp_index;
u32 isolation_config_a;
union {
u32 isolation_config_b;
struct {
u32 cvm_type : 4;
u32 reserved1 : 1;
u32 shared_gpa_boundary_active : 1;
u32 shared_gpa_boundary_bits : 6;
u32 reserved2 : 20;
u64 shared_gpa_boundary;
extern struct ms_hyperv_info ms_hyperv;
extern void * __percpu *hyperv_pcpu_input_arg;
extern void * __percpu *hyperv_pcpu_output_arg;
extern u64 hv_do_hypercall(u64 control, void *inputaddr, void *outputaddr);
extern u64 hv_do_fast_hypercall8(u16 control, u64 input8);
extern bool hv_isolation_type_snp(void);
/* Helper functions that provide a consistent pattern for checking Hyper-V hypercall status. */
static inline int hv_result(u64 status)
static inline bool hv_result_success(u64 status)
return hv_result(status) == HV_STATUS_SUCCESS;
static inline unsigned int hv_repcomp(u64 status)
/* Bits [43:32] of status have 'Reps completed' data. */
return (status & HV_HYPERCALL_REP_COMP_MASK) >>
* 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 (!hv_result_success(status))
return status;
rep_comp = hv_repcomp(status);
control |= (u64)rep_comp << HV_HYPERCALL_REP_START_OFFSET;
} while (rep_comp < rep_count);
return status;
/* Generate the guest OS identifier as described in the Hyper-V TLFS */
static inline u64 hv_generate_guest_id(u64 kernel_version)
u64 guest_id;
guest_id = (((u64)HV_LINUX_VENDOR_ID) << 48);
guest_id |= (kernel_version << 16);
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
hv_set_register(HV_REGISTER_EOM, 0);
void hv_setup_vmbus_handler(void (*handler)(void));
void hv_remove_vmbus_handler(void);
void hv_setup_stimer0_handler(void (*handler)(void));
void hv_remove_stimer0_handler(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);
extern int vmbus_interrupt;
extern int vmbus_irq;
extern bool hv_root_partition;
* 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 u64 (*hv_read_reference_counter)(void);
/* Sentinel value for an uninitialized entry in hv_vp_index array */
#define VP_INVAL U32_MAX
int __init hv_common_init(void);
void __init hv_common_free(void);
int hv_common_cpu_init(unsigned int cpu);
int hv_common_cpu_die(unsigned int cpu);
void *hv_alloc_hyperv_page(void);
void *hv_alloc_hyperv_zeroed_page(void);
void hv_free_hyperv_page(unsigned long addr);
* 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,
bool exclude_self)
int cpu, vcpu, vcpu_bank, vcpu_offset, nr_bank = 1;
int this_cpu = smp_processor_id();
int max_vcpu_bank = hv_max_vp_index / HV_VCPUS_PER_SPARSE_BANK;
/* vpset.valid_bank_mask can represent up to HV_MAX_SPARSE_VCPU_BANKS banks */
if (max_vcpu_bank >= HV_MAX_SPARSE_VCPU_BANKS)
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 <= max_vcpu_bank; vcpu_bank++)
vpset->bank_contents[vcpu_bank] = 0;
* Some banks may end up being empty but this is acceptable.
for_each_cpu(cpu, cpus) {
if (exclude_self && cpu == this_cpu)
vcpu = hv_cpu_number_to_vp_number(cpu);
if (vcpu == VP_INVAL)
return -1;
vcpu_bank = vcpu / HV_VCPUS_PER_SPARSE_BANK;
vcpu_offset = vcpu % HV_VCPUS_PER_SPARSE_BANK;
__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;
static inline int cpumask_to_vpset(struct hv_vpset *vpset,
const struct cpumask *cpus)
return __cpumask_to_vpset(vpset, cpus, false);
static inline int cpumask_to_vpset_noself(struct hv_vpset *vpset,
const struct cpumask *cpus)
return __cpumask_to_vpset(vpset, cpus, true);
void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die);
bool hv_is_hyperv_initialized(void);
bool hv_is_hibernation_supported(void);
enum hv_isolation_type hv_get_isolation_type(void);
bool hv_is_isolation_supported(void);
bool hv_isolation_type_snp(void);
u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size);
void hyperv_cleanup(void);
bool hv_query_ext_cap(u64 cap_query);
void hv_setup_dma_ops(struct device *dev, bool coherent);
void *hv_map_memory(void *addr, unsigned long size);
void hv_unmap_memory(void *addr);
#else /* CONFIG_HYPERV */
static inline bool hv_is_hyperv_initialized(void) { return false; }
static inline bool hv_is_hibernation_supported(void) { return false; }
static inline void hyperv_cleanup(void) {}
static inline bool hv_is_isolation_supported(void) { return false; }
static inline enum hv_isolation_type hv_get_isolation_type(void)
#endif /* CONFIG_HYPERV */