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 u32 hv_max_vp_index; 89 90 static int hv_cpu_init(unsigned int cpu) 91 { 92 u64 msr_vp_index; 93 94 hv_get_vp_index(msr_vp_index); 95 96 hv_vp_index[smp_processor_id()] = msr_vp_index; 97 98 if (msr_vp_index > hv_max_vp_index) 99 hv_max_vp_index = msr_vp_index; 100 101 return 0; 102 } 103 104 /* 105 * This function is to be invoked early in the boot sequence after the 106 * hypervisor has been detected. 107 * 108 * 1. Setup the hypercall page. 109 * 2. Register Hyper-V specific clocksource. 110 */ 111 void hyperv_init(void) 112 { 113 u64 guest_id; 114 union hv_x64_msr_hypercall_contents hypercall_msr; 115 116 if (x86_hyper_type != X86_HYPER_MS_HYPERV) 117 return; 118 119 /* Allocate percpu VP index */ 120 hv_vp_index = kmalloc_array(num_possible_cpus(), sizeof(*hv_vp_index), 121 GFP_KERNEL); 122 if (!hv_vp_index) 123 return; 124 125 if (cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online", 126 hv_cpu_init, NULL) < 0) 127 goto free_vp_index; 128 129 /* 130 * Setup the hypercall page and enable hypercalls. 131 * 1. Register the guest ID 132 * 2. Enable the hypercall and register the hypercall page 133 */ 134 guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0); 135 wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id); 136 137 hv_hypercall_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_RX); 138 if (hv_hypercall_pg == NULL) { 139 wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0); 140 goto free_vp_index; 141 } 142 143 rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); 144 hypercall_msr.enable = 1; 145 hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg); 146 wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); 147 148 hyper_alloc_mmu(); 149 150 /* 151 * Register Hyper-V specific clocksource. 152 */ 153 #ifdef CONFIG_HYPERV_TSCPAGE 154 if (ms_hyperv.features & HV_X64_MSR_REFERENCE_TSC_AVAILABLE) { 155 union hv_x64_msr_hypercall_contents tsc_msr; 156 157 tsc_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL); 158 if (!tsc_pg) 159 goto register_msr_cs; 160 161 hyperv_cs = &hyperv_cs_tsc; 162 163 rdmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64); 164 165 tsc_msr.enable = 1; 166 tsc_msr.guest_physical_address = vmalloc_to_pfn(tsc_pg); 167 168 wrmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64); 169 170 hyperv_cs_tsc.archdata.vclock_mode = VCLOCK_HVCLOCK; 171 172 clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100); 173 return; 174 } 175 register_msr_cs: 176 #endif 177 /* 178 * For 32 bit guests just use the MSR based mechanism for reading 179 * the partition counter. 180 */ 181 182 hyperv_cs = &hyperv_cs_msr; 183 if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE) 184 clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100); 185 186 return; 187 188 free_vp_index: 189 kfree(hv_vp_index); 190 hv_vp_index = NULL; 191 } 192 193 /* 194 * This routine is called before kexec/kdump, it does the required cleanup. 195 */ 196 void hyperv_cleanup(void) 197 { 198 union hv_x64_msr_hypercall_contents hypercall_msr; 199 200 /* Reset our OS id */ 201 wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0); 202 203 /* Reset the hypercall page */ 204 hypercall_msr.as_uint64 = 0; 205 wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); 206 207 /* Reset the TSC page */ 208 hypercall_msr.as_uint64 = 0; 209 wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64); 210 } 211 EXPORT_SYMBOL_GPL(hyperv_cleanup); 212 213 void hyperv_report_panic(struct pt_regs *regs, long err) 214 { 215 static bool panic_reported; 216 u64 guest_id; 217 218 /* 219 * We prefer to report panic on 'die' chain as we have proper 220 * registers to report, but if we miss it (e.g. on BUG()) we need 221 * to report it on 'panic'. 222 */ 223 if (panic_reported) 224 return; 225 panic_reported = true; 226 227 rdmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id); 228 229 wrmsrl(HV_X64_MSR_CRASH_P0, err); 230 wrmsrl(HV_X64_MSR_CRASH_P1, guest_id); 231 wrmsrl(HV_X64_MSR_CRASH_P2, regs->ip); 232 wrmsrl(HV_X64_MSR_CRASH_P3, regs->ax); 233 wrmsrl(HV_X64_MSR_CRASH_P4, regs->sp); 234 235 /* 236 * Let Hyper-V know there is crash data available 237 */ 238 wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY); 239 } 240 EXPORT_SYMBOL_GPL(hyperv_report_panic); 241 242 bool hv_is_hypercall_page_setup(void) 243 { 244 union hv_x64_msr_hypercall_contents hypercall_msr; 245 246 /* Check if the hypercall page is setup */ 247 hypercall_msr.as_uint64 = 0; 248 rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); 249 250 if (!hypercall_msr.enable) 251 return false; 252 253 return true; 254 } 255 EXPORT_SYMBOL_GPL(hv_is_hypercall_page_setup); 256