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 
28 struct 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 };
36 extern struct ms_hyperv_info ms_hyperv;
37 
38 extern u64 hv_do_hypercall(u64 control, void *inputaddr, void *outputaddr);
39 extern u64 hv_do_fast_hypercall8(u16 control, u64 input8);
40 
41 
42 /* Generate the guest OS identifier as described in the Hyper-V TLFS */
43 static 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 */
58 static 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 
92 void hv_setup_vmbus_irq(void (*handler)(void));
93 void hv_remove_vmbus_irq(void);
94 void hv_enable_vmbus_irq(void);
95 void hv_disable_vmbus_irq(void);
96 
97 void hv_setup_kexec_handler(void (*handler)(void));
98 void hv_remove_kexec_handler(void);
99 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs));
100 void 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  */
109 extern u32 *hv_vp_index;
110 extern 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  */
126 static inline int hv_cpu_number_to_vp_number(int cpu_number)
127 {
128 	return hv_vp_index[cpu_number];
129 }
130 
131 static 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 
166 void hyperv_report_panic(struct pt_regs *regs, long err);
167 void hyperv_report_panic_msg(phys_addr_t pa, size_t size);
168 bool hv_is_hyperv_initialized(void);
169 void hyperv_cleanup(void);
170 #else /* CONFIG_HYPERV */
171 static inline bool hv_is_hyperv_initialized(void) { return false; }
172 static inline void hyperv_cleanup(void) {}
173 #endif /* CONFIG_HYPERV */
174 
175 #if IS_ENABLED(CONFIG_HYPERV)
176 extern int hv_setup_stimer0_irq(int *irq, int *vector, void (*handler)(void));
177 extern void hv_remove_stimer0_irq(int irq);
178 #endif
179 
180 #endif
181