xref: /openbmc/linux/arch/x86/include/asm/mshyperv.h (revision 4da722ca)
1 #ifndef _ASM_X86_MSHYPER_H
2 #define _ASM_X86_MSHYPER_H
3 
4 #include <linux/types.h>
5 #include <linux/atomic.h>
6 #include <asm/hyperv.h>
7 
8 /*
9  * The below CPUID leaves are present if VersionAndFeatures.HypervisorPresent
10  * is set by CPUID(HVCPUID_VERSION_FEATURES).
11  */
12 enum hv_cpuid_function {
13 	HVCPUID_VERSION_FEATURES		= 0x00000001,
14 	HVCPUID_VENDOR_MAXFUNCTION		= 0x40000000,
15 	HVCPUID_INTERFACE			= 0x40000001,
16 
17 	/*
18 	 * The remaining functions depend on the value of
19 	 * HVCPUID_INTERFACE
20 	 */
21 	HVCPUID_VERSION				= 0x40000002,
22 	HVCPUID_FEATURES			= 0x40000003,
23 	HVCPUID_ENLIGHTENMENT_INFO		= 0x40000004,
24 	HVCPUID_IMPLEMENTATION_LIMITS		= 0x40000005,
25 };
26 
27 struct ms_hyperv_info {
28 	u32 features;
29 	u32 misc_features;
30 	u32 hints;
31 };
32 
33 extern struct ms_hyperv_info ms_hyperv;
34 
35 /*
36  * Declare the MSR used to setup pages used to communicate with the hypervisor.
37  */
38 union hv_x64_msr_hypercall_contents {
39 	u64 as_uint64;
40 	struct {
41 		u64 enable:1;
42 		u64 reserved:11;
43 		u64 guest_physical_address:52;
44 	};
45 };
46 
47 /*
48  * TSC page layout.
49  */
50 
51 struct ms_hyperv_tsc_page {
52 	volatile u32 tsc_sequence;
53 	u32 reserved1;
54 	volatile u64 tsc_scale;
55 	volatile s64 tsc_offset;
56 	u64 reserved2[509];
57 };
58 
59 /*
60  * The guest OS needs to register the guest ID with the hypervisor.
61  * The guest ID is a 64 bit entity and the structure of this ID is
62  * specified in the Hyper-V specification:
63  *
64  * msdn.microsoft.com/en-us/library/windows/hardware/ff542653%28v=vs.85%29.aspx
65  *
66  * While the current guideline does not specify how Linux guest ID(s)
67  * need to be generated, our plan is to publish the guidelines for
68  * Linux and other guest operating systems that currently are hosted
69  * on Hyper-V. The implementation here conforms to this yet
70  * unpublished guidelines.
71  *
72  *
73  * Bit(s)
74  * 63 - Indicates if the OS is Open Source or not; 1 is Open Source
75  * 62:56 - Os Type; Linux is 0x100
76  * 55:48 - Distro specific identification
77  * 47:16 - Linux kernel version number
78  * 15:0  - Distro specific identification
79  *
80  *
81  */
82 
83 #define HV_LINUX_VENDOR_ID              0x8100
84 
85 /*
86  * Generate the guest ID based on the guideline described above.
87  */
88 
89 static inline  __u64 generate_guest_id(__u64 d_info1, __u64 kernel_version,
90 				       __u64 d_info2)
91 {
92 	__u64 guest_id = 0;
93 
94 	guest_id = (((__u64)HV_LINUX_VENDOR_ID) << 48);
95 	guest_id |= (d_info1 << 48);
96 	guest_id |= (kernel_version << 16);
97 	guest_id |= d_info2;
98 
99 	return guest_id;
100 }
101 
102 
103 /* Free the message slot and signal end-of-message if required */
104 static inline void vmbus_signal_eom(struct hv_message *msg, u32 old_msg_type)
105 {
106 	/*
107 	 * On crash we're reading some other CPU's message page and we need
108 	 * to be careful: this other CPU may already had cleared the header
109 	 * and the host may already had delivered some other message there.
110 	 * In case we blindly write msg->header.message_type we're going
111 	 * to lose it. We can still lose a message of the same type but
112 	 * we count on the fact that there can only be one
113 	 * CHANNELMSG_UNLOAD_RESPONSE and we don't care about other messages
114 	 * on crash.
115 	 */
116 	if (cmpxchg(&msg->header.message_type, old_msg_type,
117 		    HVMSG_NONE) != old_msg_type)
118 		return;
119 
120 	/*
121 	 * Make sure the write to MessageType (ie set to
122 	 * HVMSG_NONE) happens before we read the
123 	 * MessagePending and EOMing. Otherwise, the EOMing
124 	 * will not deliver any more messages since there is
125 	 * no empty slot
126 	 */
127 	mb();
128 
129 	if (msg->header.message_flags.msg_pending) {
130 		/*
131 		 * This will cause message queue rescan to
132 		 * possibly deliver another msg from the
133 		 * hypervisor
134 		 */
135 		wrmsrl(HV_X64_MSR_EOM, 0);
136 	}
137 }
138 
139 #define hv_init_timer(timer, tick) wrmsrl(timer, tick)
140 #define hv_init_timer_config(config, val) wrmsrl(config, val)
141 
142 #define hv_get_simp(val) rdmsrl(HV_X64_MSR_SIMP, val)
143 #define hv_set_simp(val) wrmsrl(HV_X64_MSR_SIMP, val)
144 
145 #define hv_get_siefp(val) rdmsrl(HV_X64_MSR_SIEFP, val)
146 #define hv_set_siefp(val) wrmsrl(HV_X64_MSR_SIEFP, val)
147 
148 #define hv_get_synic_state(val) rdmsrl(HV_X64_MSR_SCONTROL, val)
149 #define hv_set_synic_state(val) wrmsrl(HV_X64_MSR_SCONTROL, val)
150 
151 #define hv_get_vp_index(index) rdmsrl(HV_X64_MSR_VP_INDEX, index)
152 
153 #define hv_get_synint_state(int_num, val) rdmsrl(int_num, val)
154 #define hv_set_synint_state(int_num, val) wrmsrl(int_num, val)
155 
156 void hyperv_callback_vector(void);
157 #ifdef CONFIG_TRACING
158 #define trace_hyperv_callback_vector hyperv_callback_vector
159 #endif
160 void hyperv_vector_handler(struct pt_regs *regs);
161 void hv_setup_vmbus_irq(void (*handler)(void));
162 void hv_remove_vmbus_irq(void);
163 
164 void hv_setup_kexec_handler(void (*handler)(void));
165 void hv_remove_kexec_handler(void);
166 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs));
167 void hv_remove_crash_handler(void);
168 
169 #if IS_ENABLED(CONFIG_HYPERV)
170 extern struct clocksource *hyperv_cs;
171 
172 void hyperv_init(void);
173 void hyperv_report_panic(struct pt_regs *regs);
174 bool hv_is_hypercall_page_setup(void);
175 void hyperv_cleanup(void);
176 #endif
177 #ifdef CONFIG_HYPERV_TSCPAGE
178 struct ms_hyperv_tsc_page *hv_get_tsc_page(void);
179 static inline u64 hv_read_tsc_page(const struct ms_hyperv_tsc_page *tsc_pg)
180 {
181 	u64 scale, offset, cur_tsc;
182 	u32 sequence;
183 
184 	/*
185 	 * The protocol for reading Hyper-V TSC page is specified in Hypervisor
186 	 * Top-Level Functional Specification ver. 3.0 and above. To get the
187 	 * reference time we must do the following:
188 	 * - READ ReferenceTscSequence
189 	 *   A special '0' value indicates the time source is unreliable and we
190 	 *   need to use something else. The currently published specification
191 	 *   versions (up to 4.0b) contain a mistake and wrongly claim '-1'
192 	 *   instead of '0' as the special value, see commit c35b82ef0294.
193 	 * - ReferenceTime =
194 	 *        ((RDTSC() * ReferenceTscScale) >> 64) + ReferenceTscOffset
195 	 * - READ ReferenceTscSequence again. In case its value has changed
196 	 *   since our first reading we need to discard ReferenceTime and repeat
197 	 *   the whole sequence as the hypervisor was updating the page in
198 	 *   between.
199 	 */
200 	do {
201 		sequence = READ_ONCE(tsc_pg->tsc_sequence);
202 		if (!sequence)
203 			return U64_MAX;
204 		/*
205 		 * Make sure we read sequence before we read other values from
206 		 * TSC page.
207 		 */
208 		smp_rmb();
209 
210 		scale = READ_ONCE(tsc_pg->tsc_scale);
211 		offset = READ_ONCE(tsc_pg->tsc_offset);
212 		cur_tsc = rdtsc_ordered();
213 
214 		/*
215 		 * Make sure we read sequence after we read all other values
216 		 * from TSC page.
217 		 */
218 		smp_rmb();
219 
220 	} while (READ_ONCE(tsc_pg->tsc_sequence) != sequence);
221 
222 	return mul_u64_u64_shr(cur_tsc, scale, 64) + offset;
223 }
224 
225 #else
226 static inline struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
227 {
228 	return NULL;
229 }
230 #endif
231 #endif
232