1/* SPDX-License-Identifier: GPL-2.0 */
  2
  3/*
  4 * Linux-specific definitions for managing interactions with Microsoft's
  5 * Hyper-V hypervisor. The definitions in this file are architecture
  6 * independent. See arch/<arch>/include/asm/mshyperv.h for definitions
  7 * that are specific to architecture <arch>.
  8 *
  9 * Definitions that are specified in the Hyper-V Top Level Functional
 10 * Spec (TLFS) should not go in this file, but should instead go in
 11 * hyperv-tlfs.h.
 12 *
 13 * Copyright (C) 2019, Microsoft, Inc.
 14 *
 15 * Author : Michael Kelley <mikelley@microsoft.com>
 16 */
 17
 18#ifndef _ASM_GENERIC_MSHYPERV_H
 19#define _ASM_GENERIC_MSHYPERV_H
 20
 21#include <linux/types.h>
 22#include <linux/atomic.h>
 23#include <linux/bitops.h>
 24#include <linux/cpumask.h>
 25#include <asm/ptrace.h>
 26#include <asm/hyperv-tlfs.h>
 27
 28struct ms_hyperv_info {
 29	u32 features;
 30	u32 misc_features;
 31	u32 hints;
 32	u32 nested_features;
 33	u32 max_vp_index;
 34	u32 max_lp_index;
 35};
 36extern struct ms_hyperv_info ms_hyperv;
 37
 38extern u64 hv_do_hypercall(u64 control, void *inputaddr, void *outputaddr);
 39extern u64 hv_do_fast_hypercall8(u16 control, u64 input8);
 40
 41
 42/* Generate the guest OS identifier as described in the Hyper-V TLFS */
 43static inline  __u64 generate_guest_id(__u64 d_info1, __u64 kernel_version,
 44				       __u64 d_info2)
 45{
 46	__u64 guest_id = 0;
 47
 48	guest_id = (((__u64)HV_LINUX_VENDOR_ID) << 48);
 49	guest_id |= (d_info1 << 48);
 50	guest_id |= (kernel_version << 16);
 51	guest_id |= d_info2;
 52
 53	return guest_id;
 54}
 55
 56
 57/* Free the message slot and signal end-of-message if required */
 58static inline void vmbus_signal_eom(struct hv_message *msg, u32 old_msg_type)
 59{
 60	/*
 61	 * On crash we're reading some other CPU's message page and we need
 62	 * to be careful: this other CPU may already had cleared the header
 63	 * and the host may already had delivered some other message there.
 64	 * In case we blindly write msg->header.message_type we're going
 65	 * to lose it. We can still lose a message of the same type but
 66	 * we count on the fact that there can only be one
 67	 * CHANNELMSG_UNLOAD_RESPONSE and we don't care about other messages
 68	 * on crash.
 69	 */
 70	if (cmpxchg(&msg->header.message_type, old_msg_type,
 71		    HVMSG_NONE) != old_msg_type)
 72		return;
 73
 74	/*
 75	 * The cmxchg() above does an implicit memory barrier to
 76	 * ensure the write to MessageType (ie set to
 77	 * HVMSG_NONE) happens before we read the
 78	 * MessagePending and EOMing. Otherwise, the EOMing
 79	 * will not deliver any more messages since there is
 80	 * no empty slot
 81	 */
 82	if (msg->header.message_flags.msg_pending) {
 83		/*
 84		 * This will cause message queue rescan to
 85		 * possibly deliver another msg from the
 86		 * hypervisor
 87		 */
 88		hv_signal_eom();
 89	}
 90}
 91
 92void hv_setup_vmbus_irq(void (*handler)(void));
 93void hv_remove_vmbus_irq(void);
 94void hv_enable_vmbus_irq(void);
 95void hv_disable_vmbus_irq(void);
 96
 97void hv_setup_kexec_handler(void (*handler)(void));
 98void hv_remove_kexec_handler(void);
 99void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs));
100void hv_remove_crash_handler(void);
101
102#if IS_ENABLED(CONFIG_HYPERV)
103/*
104 * Hypervisor's notion of virtual processor ID is different from
105 * Linux' notion of CPU ID. This information can only be retrieved
106 * in the context of the calling CPU. Setup a map for easy access
107 * to this information.
108 */
109extern u32 *hv_vp_index;
110extern u32 hv_max_vp_index;
111
112/* Sentinel value for an uninitialized entry in hv_vp_index array */
113#define VP_INVAL	U32_MAX
114
115/**
116 * hv_cpu_number_to_vp_number() - Map CPU to VP.
117 * @cpu_number: CPU number in Linux terms
118 *
119 * This function returns the mapping between the Linux processor
120 * number and the hypervisor's virtual processor number, useful
121 * in making hypercalls and such that talk about specific
122 * processors.
123 *
124 * Return: Virtual processor number in Hyper-V terms
125 */
126static inline int hv_cpu_number_to_vp_number(int cpu_number)
127{
128	return hv_vp_index[cpu_number];
129}
130
131static inline int cpumask_to_vpset(struct hv_vpset *vpset,
132				    const struct cpumask *cpus)
133{
134	int cpu, vcpu, vcpu_bank, vcpu_offset, nr_bank = 1;
135
136	/* valid_bank_mask can represent up to 64 banks */
137	if (hv_max_vp_index / 64 >= 64)
138		return 0;
139
140	/*
141	 * Clear all banks up to the maximum possible bank as hv_tlb_flush_ex
142	 * structs are not cleared between calls, we risk flushing unneeded
143	 * vCPUs otherwise.
144	 */
145	for (vcpu_bank = 0; vcpu_bank <= hv_max_vp_index / 64; vcpu_bank++)
146		vpset->bank_contents[vcpu_bank] = 0;
147
148	/*
149	 * Some banks may end up being empty but this is acceptable.
150	 */
151	for_each_cpu(cpu, cpus) {
152		vcpu = hv_cpu_number_to_vp_number(cpu);
153		if (vcpu == VP_INVAL)
154			return -1;
155		vcpu_bank = vcpu / 64;
156		vcpu_offset = vcpu % 64;
157		__set_bit(vcpu_offset, (unsigned long *)
158			  &vpset->bank_contents[vcpu_bank]);
159		if (vcpu_bank >= nr_bank)
160			nr_bank = vcpu_bank + 1;
161	}
162	vpset->valid_bank_mask = GENMASK_ULL(nr_bank - 1, 0);
163	return nr_bank;
164}
165
166void hyperv_report_panic(struct pt_regs *regs, long err);
167void hyperv_report_panic_msg(phys_addr_t pa, size_t size);
168bool hv_is_hyperv_initialized(void);
169void hyperv_cleanup(void);
170void hv_setup_sched_clock(void *sched_clock);
171#else /* CONFIG_HYPERV */
172static inline bool hv_is_hyperv_initialized(void) { return false; }
173static inline void hyperv_cleanup(void) {}
174#endif /* CONFIG_HYPERV */
175
176#if IS_ENABLED(CONFIG_HYPERV)
177extern int hv_setup_stimer0_irq(int *irq, int *vector, void (*handler)(void));
178extern void hv_remove_stimer0_irq(int irq);
179#endif
180
181#endif