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 #include <linux/slab.h> 30 #include <linux/cpuhotplug.h> 31 32 #ifdef CONFIG_HYPERV_TSCPAGE 33 34 static struct ms_hyperv_tsc_page *tsc_pg; 35 36 struct ms_hyperv_tsc_page *hv_get_tsc_page(void) 37 { 38 return tsc_pg; 39 } 40 41 static u64 read_hv_clock_tsc(struct clocksource *arg) 42 { 43 u64 current_tick = hv_read_tsc_page(tsc_pg); 44 45 if (current_tick == U64_MAX) 46 rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick); 47 48 return current_tick; 49 } 50 51 static struct clocksource hyperv_cs_tsc = { 52 .name = "hyperv_clocksource_tsc_page", 53 .rating = 400, 54 .read = read_hv_clock_tsc, 55 .mask = CLOCKSOURCE_MASK(64), 56 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 57 }; 58 #endif 59 60 static u64 read_hv_clock_msr(struct clocksource *arg) 61 { 62 u64 current_tick; 63 /* 64 * Read the partition counter to get the current tick count. This count 65 * is set to 0 when the partition is created and is incremented in 66 * 100 nanosecond units. 67 */ 68 rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick); 69 return current_tick; 70 } 71 72 static struct clocksource hyperv_cs_msr = { 73 .name = "hyperv_clocksource_msr", 74 .rating = 400, 75 .read = read_hv_clock_msr, 76 .mask = CLOCKSOURCE_MASK(64), 77 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 78 }; 79 80 void *hv_hypercall_pg; 81 EXPORT_SYMBOL_GPL(hv_hypercall_pg); 82 struct clocksource *hyperv_cs; 83 EXPORT_SYMBOL_GPL(hyperv_cs); 84 85 u32 *hv_vp_index; 86 EXPORT_SYMBOL_GPL(hv_vp_index); 87 88 static int hv_cpu_init(unsigned int cpu) 89 { 90 u64 msr_vp_index; 91 92 hv_get_vp_index(msr_vp_index); 93 94 hv_vp_index[smp_processor_id()] = msr_vp_index; 95 96 return 0; 97 } 98 99 /* 100 * This function is to be invoked early in the boot sequence after the 101 * hypervisor has been detected. 102 * 103 * 1. Setup the hypercall page. 104 * 2. Register Hyper-V specific clocksource. 105 */ 106 void hyperv_init(void) 107 { 108 u64 guest_id; 109 union hv_x64_msr_hypercall_contents hypercall_msr; 110 111 if (x86_hyper != &x86_hyper_ms_hyperv) 112 return; 113 114 /* Allocate percpu VP index */ 115 hv_vp_index = kmalloc_array(num_possible_cpus(), sizeof(*hv_vp_index), 116 GFP_KERNEL); 117 if (!hv_vp_index) 118 return; 119 120 if (cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online", 121 hv_cpu_init, NULL) < 0) 122 goto free_vp_index; 123 124 /* 125 * Setup the hypercall page and enable hypercalls. 126 * 1. Register the guest ID 127 * 2. Enable the hypercall and register the hypercall page 128 */ 129 guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0); 130 wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id); 131 132 hv_hypercall_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_RX); 133 if (hv_hypercall_pg == NULL) { 134 wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0); 135 goto free_vp_index; 136 } 137 138 rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); 139 hypercall_msr.enable = 1; 140 hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg); 141 wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); 142 143 hyper_alloc_mmu(); 144 145 /* 146 * Register Hyper-V specific clocksource. 147 */ 148 #ifdef CONFIG_HYPERV_TSCPAGE 149 if (ms_hyperv.features & HV_X64_MSR_REFERENCE_TSC_AVAILABLE) { 150 union hv_x64_msr_hypercall_contents tsc_msr; 151 152 tsc_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL); 153 if (!tsc_pg) 154 goto register_msr_cs; 155 156 hyperv_cs = &hyperv_cs_tsc; 157 158 rdmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64); 159 160 tsc_msr.enable = 1; 161 tsc_msr.guest_physical_address = vmalloc_to_pfn(tsc_pg); 162 163 wrmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64); 164 165 hyperv_cs_tsc.archdata.vclock_mode = VCLOCK_HVCLOCK; 166 167 clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100); 168 return; 169 } 170 register_msr_cs: 171 #endif 172 /* 173 * For 32 bit guests just use the MSR based mechanism for reading 174 * the partition counter. 175 */ 176 177 hyperv_cs = &hyperv_cs_msr; 178 if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE) 179 clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100); 180 181 return; 182 183 free_vp_index: 184 kfree(hv_vp_index); 185 hv_vp_index = NULL; 186 } 187 188 /* 189 * This routine is called before kexec/kdump, it does the required cleanup. 190 */ 191 void hyperv_cleanup(void) 192 { 193 union hv_x64_msr_hypercall_contents hypercall_msr; 194 195 /* Reset our OS id */ 196 wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0); 197 198 /* Reset the hypercall page */ 199 hypercall_msr.as_uint64 = 0; 200 wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); 201 202 /* Reset the TSC page */ 203 hypercall_msr.as_uint64 = 0; 204 wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64); 205 } 206 EXPORT_SYMBOL_GPL(hyperv_cleanup); 207 208 void hyperv_report_panic(struct pt_regs *regs) 209 { 210 static bool panic_reported; 211 212 /* 213 * We prefer to report panic on 'die' chain as we have proper 214 * registers to report, but if we miss it (e.g. on BUG()) we need 215 * to report it on 'panic'. 216 */ 217 if (panic_reported) 218 return; 219 panic_reported = true; 220 221 wrmsrl(HV_X64_MSR_CRASH_P0, regs->ip); 222 wrmsrl(HV_X64_MSR_CRASH_P1, regs->ax); 223 wrmsrl(HV_X64_MSR_CRASH_P2, regs->bx); 224 wrmsrl(HV_X64_MSR_CRASH_P3, regs->cx); 225 wrmsrl(HV_X64_MSR_CRASH_P4, regs->dx); 226 227 /* 228 * Let Hyper-V know there is crash data available 229 */ 230 wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY); 231 } 232 EXPORT_SYMBOL_GPL(hyperv_report_panic); 233 234 bool hv_is_hypercall_page_setup(void) 235 { 236 union hv_x64_msr_hypercall_contents hypercall_msr; 237 238 /* Check if the hypercall page is setup */ 239 hypercall_msr.as_uint64 = 0; 240 rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); 241 242 if (!hypercall_msr.enable) 243 return false; 244 245 return true; 246 } 247 EXPORT_SYMBOL_GPL(hv_is_hypercall_page_setup); 248