arch/x86/hyperv/hv_init.c

   1 /*
   2  * X86 specific Hyper-V initialization code.
   3  *
   4  * Copyright (C) 2016, Microsoft, Inc.
   5  *
   6  * Author : K. Y. Srinivasan <kys@microsoft.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License version 2 as published
  10  * by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  15  * NON INFRINGEMENT.  See the GNU General Public License for more
  16  * details.
  17  *
  18  */
  19
  20 #include <linux/types.h>
  21 #include <asm/hypervisor.h>
  22 #include <asm/hyperv.h>
  23 #include <asm/mshyperv.h>
  24 #include <linux/version.h>
  25 #include <linux/vmalloc.h>
  26 #include <linux/mm.h>
  27 #include <linux/clockchips.h>
  28 #include <linux/hyperv.h>
  29
  30 #ifdef CONFIG_HYPERV_TSCPAGE
  31
  32 static struct ms_hyperv_tsc_page *tsc_pg;
  33
  34 struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
  35 {
  36         return tsc_pg;
  37 }
  38
  39 static u64 read_hv_clock_tsc(struct clocksource *arg)
  40 {
  41         u64 current_tick = hv_read_tsc_page(tsc_pg);
  42
  43         if (current_tick == U64_MAX)
  44                 rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
  45
  46         return current_tick;
  47 }
  48
  49 static struct clocksource hyperv_cs_tsc = {
  50                 .name           = "hyperv_clocksource_tsc_page",
  51                 .rating         = 400,
  52                 .read           = read_hv_clock_tsc,
  53                 .mask           = CLOCKSOURCE_MASK(64),
  54                 .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  55 };
  56 #endif
  57
  58 static u64 read_hv_clock_msr(struct clocksource *arg)
  59 {
  60         u64 current_tick;
  61         /*
  62          * Read the partition counter to get the current tick count. This count
  63          * is set to 0 when the partition is created and is incremented in
  64          * 100 nanosecond units.
  65          */
  66         rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
  67         return current_tick;
  68 }
  69
  70 static struct clocksource hyperv_cs_msr = {
  71         .name           = "hyperv_clocksource_msr",
  72         .rating         = 400,
  73         .read           = read_hv_clock_msr,
  74         .mask           = CLOCKSOURCE_MASK(64),
  75         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  76 };
  77
  78 static void *hypercall_pg;
  79 struct clocksource *hyperv_cs;
  80 EXPORT_SYMBOL_GPL(hyperv_cs);
  81
  82 /*
  83  * This function is to be invoked early in the boot sequence after the
  84  * hypervisor has been detected.
  85  *
  86  * 1. Setup the hypercall page.
  87  * 2. Register Hyper-V specific clocksource.
  88  */
  89 void hyperv_init(void)
  90 {
  91         u64 guest_id;
  92         union hv_x64_msr_hypercall_contents hypercall_msr;
  93
  94         if (x86_hyper != &x86_hyper_ms_hyperv)
  95                 return;
  96
  97         /*
  98          * Setup the hypercall page and enable hypercalls.
  99          * 1. Register the guest ID
 100          * 2. Enable the hypercall and register the hypercall page
 101          */
 102         guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0);
 103         wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
 104
 105         hypercall_pg  = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_RX);
 106         if (hypercall_pg == NULL) {
 107                 wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
 108                 return;
 109         }
 110
 111         rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 112         hypercall_msr.enable = 1;
 113         hypercall_msr.guest_physical_address = vmalloc_to_pfn(hypercall_pg);
 114         wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 115
 116         /*
 117          * Register Hyper-V specific clocksource.
 118          */
 119 #ifdef CONFIG_HYPERV_TSCPAGE
 120         if (ms_hyperv.features & HV_X64_MSR_REFERENCE_TSC_AVAILABLE) {
 121                 union hv_x64_msr_hypercall_contents tsc_msr;
 122
 123                 tsc_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
 124                 if (!tsc_pg)
 125                         goto register_msr_cs;
 126
 127                 hyperv_cs = &hyperv_cs_tsc;
 128
 129                 rdmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
 130
 131                 tsc_msr.enable = 1;
 132                 tsc_msr.guest_physical_address = vmalloc_to_pfn(tsc_pg);
 133
 134                 wrmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
 135
 136                 hyperv_cs_tsc.archdata.vclock_mode = VCLOCK_HVCLOCK;
 137
 138                 clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);
 139                 return;
 140         }
 141 register_msr_cs:
 142 #endif
 143         /*
 144          * For 32 bit guests just use the MSR based mechanism for reading
 145          * the partition counter.
 146          */
 147
 148         hyperv_cs = &hyperv_cs_msr;
 149         if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
 150                 clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);
 151 }
 152
 153 /*
 154  * This routine is called before kexec/kdump, it does the required cleanup.
 155  */
 156 void hyperv_cleanup(void)
 157 {
 158         union hv_x64_msr_hypercall_contents hypercall_msr;
 159
 160         /* Reset our OS id */
 161         wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
 162
 163         /* Reset the hypercall page */
 164         hypercall_msr.as_uint64 = 0;
 165         wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 166
 167         /* Reset the TSC page */
 168         hypercall_msr.as_uint64 = 0;
 169         wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64);
 170 }
 171 EXPORT_SYMBOL_GPL(hyperv_cleanup);
 172
 173 /*
 174  * hv_do_hypercall- Invoke the specified hypercall
 175  */
 176 u64 hv_do_hypercall(u64 control, void *input, void *output)
 177 {
 178         u64 input_address = (input) ? virt_to_phys(input) : 0;
 179         u64 output_address = (output) ? virt_to_phys(output) : 0;
 180 #ifdef CONFIG_X86_64
 181         u64 hv_status = 0;
 182
 183         if (!hypercall_pg)
 184                 return (u64)ULLONG_MAX;
 185
 186         __asm__ __volatile__("mov %0, %%r8" : : "r" (output_address) : "r8");
 187         __asm__ __volatile__("call *%3" : "=a" (hv_status) :
 188                              "c" (control), "d" (input_address),
 189                              "m" (hypercall_pg));
 190
 191         return hv_status;
 192
 193 #else
 194
 195         u32 control_hi = control >> 32;
 196         u32 control_lo = control & 0xFFFFFFFF;
 197         u32 hv_status_hi = 1;
 198         u32 hv_status_lo = 1;
 199         u32 input_address_hi = input_address >> 32;
 200         u32 input_address_lo = input_address & 0xFFFFFFFF;
 201         u32 output_address_hi = output_address >> 32;
 202         u32 output_address_lo = output_address & 0xFFFFFFFF;
 203
 204         if (!hypercall_pg)
 205                 return (u64)ULLONG_MAX;
 206
 207         __asm__ __volatile__ ("call *%8" : "=d"(hv_status_hi),
 208                               "=a"(hv_status_lo) : "d" (control_hi),
 209                               "a" (control_lo), "b" (input_address_hi),
 210                               "c" (input_address_lo), "D"(output_address_hi),
 211                               "S"(output_address_lo), "m" (hypercall_pg));
 212
 213         return hv_status_lo | ((u64)hv_status_hi << 32);
 214 #endif /* !x86_64 */
 215 }
 216 EXPORT_SYMBOL_GPL(hv_do_hypercall);
 217
 218 void hyperv_report_panic(struct pt_regs *regs)
 219 {
 220         static bool panic_reported;
 221
 222         /*
 223          * We prefer to report panic on 'die' chain as we have proper
 224          * registers to report, but if we miss it (e.g. on BUG()) we need
 225          * to report it on 'panic'.
 226          */
 227         if (panic_reported)
 228                 return;
 229         panic_reported = true;
 230
 231         wrmsrl(HV_X64_MSR_CRASH_P0, regs->ip);
 232         wrmsrl(HV_X64_MSR_CRASH_P1, regs->ax);
 233         wrmsrl(HV_X64_MSR_CRASH_P2, regs->bx);
 234         wrmsrl(HV_X64_MSR_CRASH_P3, regs->cx);
 235         wrmsrl(HV_X64_MSR_CRASH_P4, regs->dx);
 236
 237         /*
 238          * Let Hyper-V know there is crash data available
 239          */
 240         wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
 241 }
 242 EXPORT_SYMBOL_GPL(hyperv_report_panic);
 243
 244 bool hv_is_hypercall_page_setup(void)
 245 {
 246         union hv_x64_msr_hypercall_contents hypercall_msr;
 247
 248         /* Check if the hypercall page is setup */
 249         hypercall_msr.as_uint64 = 0;
 250         rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 251
 252         if (!hypercall_msr.enable)
 253                 return false;
 254
 255         return true;
 256 }
 257 EXPORT_SYMBOL_GPL(hv_is_hypercall_page_setup);