arch/x86/include/asm/mshyperv.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_X86_MSHYPER_H
   3 #define _ASM_X86_MSHYPER_H
   4
   5 #include <linux/types.h>
   6 #include <linux/atomic.h>
   7 #include <linux/nmi.h>
   8 #include <asm/io.h>
   9 #include <asm/hyperv.h>
  10
  11 /*
  12  * The below CPUID leaves are present if VersionAndFeatures.HypervisorPresent
  13  * is set by CPUID(HVCPUID_VERSION_FEATURES).
  14  */
  15 enum hv_cpuid_function {
  16         HVCPUID_VERSION_FEATURES                = 0x00000001,
  17         HVCPUID_VENDOR_MAXFUNCTION              = 0x40000000,
  18         HVCPUID_INTERFACE                       = 0x40000001,
  19
  20         /*
  21          * The remaining functions depend on the value of
  22          * HVCPUID_INTERFACE
  23          */
  24         HVCPUID_VERSION                         = 0x40000002,
  25         HVCPUID_FEATURES                        = 0x40000003,
  26         HVCPUID_ENLIGHTENMENT_INFO              = 0x40000004,
  27         HVCPUID_IMPLEMENTATION_LIMITS           = 0x40000005,
  28 };
  29
  30 struct ms_hyperv_info {
  31         u32 features;
  32         u32 misc_features;
  33         u32 hints;
  34         u32 max_vp_index;
  35         u32 max_lp_index;
  36 };
  37
  38 extern struct ms_hyperv_info ms_hyperv;
  39
  40 /*
  41  * Declare the MSR used to setup pages used to communicate with the hypervisor.
  42  */
  43 union hv_x64_msr_hypercall_contents {
  44         u64 as_uint64;
  45         struct {
  46                 u64 enable:1;
  47                 u64 reserved:11;
  48                 u64 guest_physical_address:52;
  49         };
  50 };
  51
  52 /*
  53  * TSC page layout.
  54  */
  55
  56 struct ms_hyperv_tsc_page {
  57         volatile u32 tsc_sequence;
  58         u32 reserved1;
  59         volatile u64 tsc_scale;
  60         volatile s64 tsc_offset;
  61         u64 reserved2[509];
  62 };
  63
  64 /*
  65  * The guest OS needs to register the guest ID with the hypervisor.
  66  * The guest ID is a 64 bit entity and the structure of this ID is
  67  * specified in the Hyper-V specification:
  68  *
  69  * msdn.microsoft.com/en-us/library/windows/hardware/ff542653%28v=vs.85%29.aspx
  70  *
  71  * While the current guideline does not specify how Linux guest ID(s)
  72  * need to be generated, our plan is to publish the guidelines for
  73  * Linux and other guest operating systems that currently are hosted
  74  * on Hyper-V. The implementation here conforms to this yet
  75  * unpublished guidelines.
  76  *
  77  *
  78  * Bit(s)
  79  * 63 - Indicates if the OS is Open Source or not; 1 is Open Source
  80  * 62:56 - Os Type; Linux is 0x100
  81  * 55:48 - Distro specific identification
  82  * 47:16 - Linux kernel version number
  83  * 15:0  - Distro specific identification
  84  *
  85  *
  86  */
  87
  88 #define HV_LINUX_VENDOR_ID              0x8100
  89
  90 /*
  91  * Generate the guest ID based on the guideline described above.
  92  */
  93
  94 static inline  __u64 generate_guest_id(__u64 d_info1, __u64 kernel_version,
  95                                        __u64 d_info2)
  96 {
  97         __u64 guest_id = 0;
  98
  99         guest_id = (((__u64)HV_LINUX_VENDOR_ID) << 48);
 100         guest_id |= (d_info1 << 48);
 101         guest_id |= (kernel_version << 16);
 102         guest_id |= d_info2;
 103
 104         return guest_id;
 105 }
 106
 107
 108 /* Free the message slot and signal end-of-message if required */
 109 static inline void vmbus_signal_eom(struct hv_message *msg, u32 old_msg_type)
 110 {
 111         /*
 112          * On crash we're reading some other CPU's message page and we need
 113          * to be careful: this other CPU may already had cleared the header
 114          * and the host may already had delivered some other message there.
 115          * In case we blindly write msg->header.message_type we're going
 116          * to lose it. We can still lose a message of the same type but
 117          * we count on the fact that there can only be one
 118          * CHANNELMSG_UNLOAD_RESPONSE and we don't care about other messages
 119          * on crash.
 120          */
 121         if (cmpxchg(&msg->header.message_type, old_msg_type,
 122                     HVMSG_NONE) != old_msg_type)
 123                 return;
 124
 125         /*
 126          * Make sure the write to MessageType (ie set to
 127          * HVMSG_NONE) happens before we read the
 128          * MessagePending and EOMing. Otherwise, the EOMing
 129          * will not deliver any more messages since there is
 130          * no empty slot
 131          */
 132         mb();
 133
 134         if (msg->header.message_flags.msg_pending) {
 135                 /*
 136                  * This will cause message queue rescan to
 137                  * possibly deliver another msg from the
 138                  * hypervisor
 139                  */
 140                 wrmsrl(HV_X64_MSR_EOM, 0);
 141         }
 142 }
 143
 144 #define hv_init_timer(timer, tick) wrmsrl(timer, tick)
 145 #define hv_init_timer_config(config, val) wrmsrl(config, val)
 146
 147 #define hv_get_simp(val) rdmsrl(HV_X64_MSR_SIMP, val)
 148 #define hv_set_simp(val) wrmsrl(HV_X64_MSR_SIMP, val)
 149
 150 #define hv_get_siefp(val) rdmsrl(HV_X64_MSR_SIEFP, val)
 151 #define hv_set_siefp(val) wrmsrl(HV_X64_MSR_SIEFP, val)
 152
 153 #define hv_get_synic_state(val) rdmsrl(HV_X64_MSR_SCONTROL, val)
 154 #define hv_set_synic_state(val) wrmsrl(HV_X64_MSR_SCONTROL, val)
 155
 156 #define hv_get_vp_index(index) rdmsrl(HV_X64_MSR_VP_INDEX, index)
 157
 158 #define hv_get_synint_state(int_num, val) rdmsrl(int_num, val)
 159 #define hv_set_synint_state(int_num, val) wrmsrl(int_num, val)
 160
 161 void hyperv_callback_vector(void);
 162 #ifdef CONFIG_TRACING
 163 #define trace_hyperv_callback_vector hyperv_callback_vector
 164 #endif
 165 void hyperv_vector_handler(struct pt_regs *regs);
 166 void hv_setup_vmbus_irq(void (*handler)(void));
 167 void hv_remove_vmbus_irq(void);
 168
 169 void hv_setup_kexec_handler(void (*handler)(void));
 170 void hv_remove_kexec_handler(void);
 171 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs));
 172 void hv_remove_crash_handler(void);
 173
 174 #if IS_ENABLED(CONFIG_HYPERV)
 175 extern struct clocksource *hyperv_cs;
 176 extern void *hv_hypercall_pg;
 177
 178 static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
 179 {
 180         u64 input_address = input ? virt_to_phys(input) : 0;
 181         u64 output_address = output ? virt_to_phys(output) : 0;
 182         u64 hv_status;
 183
 184 #ifdef CONFIG_X86_64
 185         if (!hv_hypercall_pg)
 186                 return U64_MAX;
 187
 188         __asm__ __volatile__("mov %4, %%r8\n"
 189                              "call *%5"
 190                              : "=a" (hv_status), ASM_CALL_CONSTRAINT,
 191                                "+c" (control), "+d" (input_address)
 192                              :  "r" (output_address), "m" (hv_hypercall_pg)
 193                              : "cc", "memory", "r8", "r9", "r10", "r11");
 194 #else
 195         u32 input_address_hi = upper_32_bits(input_address);
 196         u32 input_address_lo = lower_32_bits(input_address);
 197         u32 output_address_hi = upper_32_bits(output_address);
 198         u32 output_address_lo = lower_32_bits(output_address);
 199
 200         if (!hv_hypercall_pg)
 201                 return U64_MAX;
 202
 203         __asm__ __volatile__("call *%7"
 204                              : "=A" (hv_status),
 205                                "+c" (input_address_lo), ASM_CALL_CONSTRAINT
 206                              : "A" (control),
 207                                "b" (input_address_hi),
 208                                "D"(output_address_hi), "S"(output_address_lo),
 209                                "m" (hv_hypercall_pg)
 210                              : "cc", "memory");
 211 #endif /* !x86_64 */
 212         return hv_status;
 213 }
 214
 215 #define HV_HYPERCALL_RESULT_MASK        GENMASK_ULL(15, 0)
 216 #define HV_HYPERCALL_FAST_BIT           BIT(16)
 217 #define HV_HYPERCALL_VARHEAD_OFFSET     17
 218 #define HV_HYPERCALL_REP_COMP_OFFSET    32
 219 #define HV_HYPERCALL_REP_COMP_MASK      GENMASK_ULL(43, 32)
 220 #define HV_HYPERCALL_REP_START_OFFSET   48
 221 #define HV_HYPERCALL_REP_START_MASK     GENMASK_ULL(59, 48)
 222
 223 /* Fast hypercall with 8 bytes of input and no output */
 224 static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1)
 225 {
 226         u64 hv_status, control = (u64)code | HV_HYPERCALL_FAST_BIT;
 227
 228 #ifdef CONFIG_X86_64
 229         {
 230                 __asm__ __volatile__("call *%4"
 231                                      : "=a" (hv_status), ASM_CALL_CONSTRAINT,
 232                                        "+c" (control), "+d" (input1)
 233                                      : "m" (hv_hypercall_pg)
 234                                      : "cc", "r8", "r9", "r10", "r11");
 235         }
 236 #else
 237         {
 238                 u32 input1_hi = upper_32_bits(input1);
 239                 u32 input1_lo = lower_32_bits(input1);
 240
 241                 __asm__ __volatile__ ("call *%5"
 242                                       : "=A"(hv_status),
 243                                         "+c"(input1_lo),
 244                                         ASM_CALL_CONSTRAINT
 245                                       : "A" (control),
 246                                         "b" (input1_hi),
 247                                         "m" (hv_hypercall_pg)
 248                                       : "cc", "edi", "esi");
 249         }
 250 #endif
 251                 return hv_status;
 252 }
 253
 254 /*
 255  * Rep hypercalls. Callers of this functions are supposed to ensure that
 256  * rep_count and varhead_size comply with Hyper-V hypercall definition.
 257  */
 258 static inline u64 hv_do_rep_hypercall(u16 code, u16 rep_count, u16 varhead_size,
 259                                       void *input, void *output)
 260 {
 261         u64 control = code;
 262         u64 status;
 263         u16 rep_comp;
 264
 265         control |= (u64)varhead_size << HV_HYPERCALL_VARHEAD_OFFSET;
 266         control |= (u64)rep_count << HV_HYPERCALL_REP_COMP_OFFSET;
 267
 268         do {
 269                 status = hv_do_hypercall(control, input, output);
 270                 if ((status & HV_HYPERCALL_RESULT_MASK) != HV_STATUS_SUCCESS)
 271                         return status;
 272
 273                 /* Bits 32-43 of status have 'Reps completed' data. */
 274                 rep_comp = (status & HV_HYPERCALL_REP_COMP_MASK) >>
 275                         HV_HYPERCALL_REP_COMP_OFFSET;
 276
 277                 control &= ~HV_HYPERCALL_REP_START_MASK;
 278                 control |= (u64)rep_comp << HV_HYPERCALL_REP_START_OFFSET;
 279
 280                 touch_nmi_watchdog();
 281         } while (rep_comp < rep_count);
 282
 283         return status;
 284 }
 285
 286 /*
 287  * Hypervisor's notion of virtual processor ID is different from
 288  * Linux' notion of CPU ID. This information can only be retrieved
 289  * in the context of the calling CPU. Setup a map for easy access
 290  * to this information.
 291  */
 292 extern u32 *hv_vp_index;
 293 extern u32 hv_max_vp_index;
 294
 295 /**
 296  * hv_cpu_number_to_vp_number() - Map CPU to VP.
 297  * @cpu_number: CPU number in Linux terms
 298  *
 299  * This function returns the mapping between the Linux processor
 300  * number and the hypervisor's virtual processor number, useful
 301  * in making hypercalls and such that talk about specific
 302  * processors.
 303  *
 304  * Return: Virtual processor number in Hyper-V terms
 305  */
 306 static inline int hv_cpu_number_to_vp_number(int cpu_number)
 307 {
 308         return hv_vp_index[cpu_number];
 309 }
 310
 311 void hyperv_init(void);
 312 void hyperv_setup_mmu_ops(void);
 313 void hyper_alloc_mmu(void);
 314 void hyperv_report_panic(struct pt_regs *regs);
 315 bool hv_is_hypercall_page_setup(void);
 316 void hyperv_cleanup(void);
 317 #else /* CONFIG_HYPERV */
 318 static inline void hyperv_init(void) {}
 319 static inline bool hv_is_hypercall_page_setup(void) { return false; }
 320 static inline void hyperv_cleanup(void) {}
 321 static inline void hyperv_setup_mmu_ops(void) {}
 322 #endif /* CONFIG_HYPERV */
 323
 324 #ifdef CONFIG_HYPERV_TSCPAGE
 325 struct ms_hyperv_tsc_page *hv_get_tsc_page(void);
 326 static inline u64 hv_read_tsc_page(const struct ms_hyperv_tsc_page *tsc_pg)
 327 {
 328         u64 scale, offset, cur_tsc;
 329         u32 sequence;
 330
 331         /*
 332          * The protocol for reading Hyper-V TSC page is specified in Hypervisor
 333          * Top-Level Functional Specification ver. 3.0 and above. To get the
 334          * reference time we must do the following:
 335          * - READ ReferenceTscSequence
 336          *   A special '0' value indicates the time source is unreliable and we
 337          *   need to use something else. The currently published specification
 338          *   versions (up to 4.0b) contain a mistake and wrongly claim '-1'
 339          *   instead of '0' as the special value, see commit c35b82ef0294.
 340          * - ReferenceTime =
 341          *        ((RDTSC() * ReferenceTscScale) >> 64) + ReferenceTscOffset
 342          * - READ ReferenceTscSequence again. In case its value has changed
 343          *   since our first reading we need to discard ReferenceTime and repeat
 344          *   the whole sequence as the hypervisor was updating the page in
 345          *   between.
 346          */
 347         do {
 348                 sequence = READ_ONCE(tsc_pg->tsc_sequence);
 349                 if (!sequence)
 350                         return U64_MAX;
 351                 /*
 352                  * Make sure we read sequence before we read other values from
 353                  * TSC page.
 354                  */
 355                 smp_rmb();
 356
 357                 scale = READ_ONCE(tsc_pg->tsc_scale);
 358                 offset = READ_ONCE(tsc_pg->tsc_offset);
 359                 cur_tsc = rdtsc_ordered();
 360
 361                 /*
 362                  * Make sure we read sequence after we read all other values
 363                  * from TSC page.
 364                  */
 365                 smp_rmb();
 366
 367         } while (READ_ONCE(tsc_pg->tsc_sequence) != sequence);
 368
 369         return mul_u64_u64_shr(cur_tsc, scale, 64) + offset;
 370 }
 371
 372 #else
 373 static inline struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
 374 {
 375         return NULL;
 376 }
 377 #endif
 378 #endif