1 /* 2 * VMware Detection code. 3 * 4 * Copyright (C) 2008, VMware, Inc. 5 * Author : Alok N Kataria <akataria@vmware.com> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 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 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 21 * 22 */ 23 24 #include <linux/dmi.h> 25 #include <linux/init.h> 26 #include <linux/export.h> 27 #include <linux/clocksource.h> 28 #include <asm/div64.h> 29 #include <asm/x86_init.h> 30 #include <asm/hypervisor.h> 31 #include <asm/timer.h> 32 #include <asm/apic.h> 33 #include <asm/vmware.h> 34 35 #undef pr_fmt 36 #define pr_fmt(fmt) "vmware: " fmt 37 38 #define CPUID_VMWARE_INFO_LEAF 0x40000000 39 #define CPUID_VMWARE_FEATURES_LEAF 0x40000010 40 #define CPUID_VMWARE_FEATURES_ECX_VMMCALL BIT(0) 41 #define CPUID_VMWARE_FEATURES_ECX_VMCALL BIT(1) 42 43 #define VMWARE_HYPERVISOR_MAGIC 0x564D5868 44 45 #define VMWARE_CMD_GETVERSION 10 46 #define VMWARE_CMD_GETHZ 45 47 #define VMWARE_CMD_GETVCPU_INFO 68 48 #define VMWARE_CMD_LEGACY_X2APIC 3 49 #define VMWARE_CMD_VCPU_RESERVED 31 50 51 #define VMWARE_PORT(cmd, eax, ebx, ecx, edx) \ 52 __asm__("inl (%%dx)" : \ 53 "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) : \ 54 "a"(VMWARE_HYPERVISOR_MAGIC), \ 55 "c"(VMWARE_CMD_##cmd), \ 56 "d"(VMWARE_HYPERVISOR_PORT), "b"(UINT_MAX) : \ 57 "memory") 58 59 #define VMWARE_VMCALL(cmd, eax, ebx, ecx, edx) \ 60 __asm__("vmcall" : \ 61 "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) : \ 62 "a"(VMWARE_HYPERVISOR_MAGIC), \ 63 "c"(VMWARE_CMD_##cmd), \ 64 "d"(0), "b"(UINT_MAX) : \ 65 "memory") 66 67 #define VMWARE_VMMCALL(cmd, eax, ebx, ecx, edx) \ 68 __asm__("vmmcall" : \ 69 "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) : \ 70 "a"(VMWARE_HYPERVISOR_MAGIC), \ 71 "c"(VMWARE_CMD_##cmd), \ 72 "d"(0), "b"(UINT_MAX) : \ 73 "memory") 74 75 #define VMWARE_CMD(cmd, eax, ebx, ecx, edx) do { \ 76 switch (vmware_hypercall_mode) { \ 77 case CPUID_VMWARE_FEATURES_ECX_VMCALL: \ 78 VMWARE_VMCALL(cmd, eax, ebx, ecx, edx); \ 79 break; \ 80 case CPUID_VMWARE_FEATURES_ECX_VMMCALL: \ 81 VMWARE_VMMCALL(cmd, eax, ebx, ecx, edx); \ 82 break; \ 83 default: \ 84 VMWARE_PORT(cmd, eax, ebx, ecx, edx); \ 85 break; \ 86 } \ 87 } while (0) 88 89 static unsigned long vmware_tsc_khz __ro_after_init; 90 static u8 vmware_hypercall_mode __ro_after_init; 91 92 static inline int __vmware_platform(void) 93 { 94 uint32_t eax, ebx, ecx, edx; 95 VMWARE_CMD(GETVERSION, eax, ebx, ecx, edx); 96 return eax != (uint32_t)-1 && ebx == VMWARE_HYPERVISOR_MAGIC; 97 } 98 99 static unsigned long vmware_get_tsc_khz(void) 100 { 101 return vmware_tsc_khz; 102 } 103 104 #ifdef CONFIG_PARAVIRT 105 static struct cyc2ns_data vmware_cyc2ns __ro_after_init; 106 static int vmw_sched_clock __initdata = 1; 107 108 static __init int setup_vmw_sched_clock(char *s) 109 { 110 vmw_sched_clock = 0; 111 return 0; 112 } 113 early_param("no-vmw-sched-clock", setup_vmw_sched_clock); 114 115 static unsigned long long notrace vmware_sched_clock(void) 116 { 117 unsigned long long ns; 118 119 ns = mul_u64_u32_shr(rdtsc(), vmware_cyc2ns.cyc2ns_mul, 120 vmware_cyc2ns.cyc2ns_shift); 121 ns -= vmware_cyc2ns.cyc2ns_offset; 122 return ns; 123 } 124 125 static void __init vmware_sched_clock_setup(void) 126 { 127 struct cyc2ns_data *d = &vmware_cyc2ns; 128 unsigned long long tsc_now = rdtsc(); 129 130 clocks_calc_mult_shift(&d->cyc2ns_mul, &d->cyc2ns_shift, 131 vmware_tsc_khz, NSEC_PER_MSEC, 0); 132 d->cyc2ns_offset = mul_u64_u32_shr(tsc_now, d->cyc2ns_mul, 133 d->cyc2ns_shift); 134 135 pv_ops.time.sched_clock = vmware_sched_clock; 136 pr_info("using sched offset of %llu ns\n", d->cyc2ns_offset); 137 } 138 139 static void __init vmware_paravirt_ops_setup(void) 140 { 141 pv_info.name = "VMware hypervisor"; 142 pv_ops.cpu.io_delay = paravirt_nop; 143 144 if (vmware_tsc_khz && vmw_sched_clock) 145 vmware_sched_clock_setup(); 146 } 147 #else 148 #define vmware_paravirt_ops_setup() do {} while (0) 149 #endif 150 151 /* 152 * VMware hypervisor takes care of exporting a reliable TSC to the guest. 153 * Still, due to timing difference when running on virtual cpus, the TSC can 154 * be marked as unstable in some cases. For example, the TSC sync check at 155 * bootup can fail due to a marginal offset between vcpus' TSCs (though the 156 * TSCs do not drift from each other). Also, the ACPI PM timer clocksource 157 * is not suitable as a watchdog when running on a hypervisor because the 158 * kernel may miss a wrap of the counter if the vcpu is descheduled for a 159 * long time. To skip these checks at runtime we set these capability bits, 160 * so that the kernel could just trust the hypervisor with providing a 161 * reliable virtual TSC that is suitable for timekeeping. 162 */ 163 static void __init vmware_set_capabilities(void) 164 { 165 setup_force_cpu_cap(X86_FEATURE_CONSTANT_TSC); 166 setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE); 167 if (vmware_hypercall_mode == CPUID_VMWARE_FEATURES_ECX_VMCALL) 168 setup_force_cpu_cap(X86_FEATURE_VMCALL); 169 else if (vmware_hypercall_mode == CPUID_VMWARE_FEATURES_ECX_VMMCALL) 170 setup_force_cpu_cap(X86_FEATURE_VMW_VMMCALL); 171 } 172 173 static void __init vmware_platform_setup(void) 174 { 175 uint32_t eax, ebx, ecx, edx; 176 uint64_t lpj, tsc_khz; 177 178 VMWARE_CMD(GETHZ, eax, ebx, ecx, edx); 179 180 if (ebx != UINT_MAX) { 181 lpj = tsc_khz = eax | (((uint64_t)ebx) << 32); 182 do_div(tsc_khz, 1000); 183 WARN_ON(tsc_khz >> 32); 184 pr_info("TSC freq read from hypervisor : %lu.%03lu MHz\n", 185 (unsigned long) tsc_khz / 1000, 186 (unsigned long) tsc_khz % 1000); 187 188 if (!preset_lpj) { 189 do_div(lpj, HZ); 190 preset_lpj = lpj; 191 } 192 193 vmware_tsc_khz = tsc_khz; 194 x86_platform.calibrate_tsc = vmware_get_tsc_khz; 195 x86_platform.calibrate_cpu = vmware_get_tsc_khz; 196 197 #ifdef CONFIG_X86_LOCAL_APIC 198 /* Skip lapic calibration since we know the bus frequency. */ 199 lapic_timer_period = ecx / HZ; 200 pr_info("Host bus clock speed read from hypervisor : %u Hz\n", 201 ecx); 202 #endif 203 } else { 204 pr_warn("Failed to get TSC freq from the hypervisor\n"); 205 } 206 207 vmware_paravirt_ops_setup(); 208 209 #ifdef CONFIG_X86_IO_APIC 210 no_timer_check = 1; 211 #endif 212 213 vmware_set_capabilities(); 214 } 215 216 static u8 vmware_select_hypercall(void) 217 { 218 int eax, ebx, ecx, edx; 219 220 cpuid(CPUID_VMWARE_FEATURES_LEAF, &eax, &ebx, &ecx, &edx); 221 return (ecx & (CPUID_VMWARE_FEATURES_ECX_VMMCALL | 222 CPUID_VMWARE_FEATURES_ECX_VMCALL)); 223 } 224 225 /* 226 * While checking the dmi string information, just checking the product 227 * serial key should be enough, as this will always have a VMware 228 * specific string when running under VMware hypervisor. 229 * If !boot_cpu_has(X86_FEATURE_HYPERVISOR), vmware_hypercall_mode 230 * intentionally defaults to 0. 231 */ 232 static uint32_t __init vmware_platform(void) 233 { 234 if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) { 235 unsigned int eax; 236 unsigned int hyper_vendor_id[3]; 237 238 cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &hyper_vendor_id[0], 239 &hyper_vendor_id[1], &hyper_vendor_id[2]); 240 if (!memcmp(hyper_vendor_id, "VMwareVMware", 12)) { 241 if (eax >= CPUID_VMWARE_FEATURES_LEAF) 242 vmware_hypercall_mode = 243 vmware_select_hypercall(); 244 245 pr_info("hypercall mode: 0x%02x\n", 246 (unsigned int) vmware_hypercall_mode); 247 248 return CPUID_VMWARE_INFO_LEAF; 249 } 250 } else if (dmi_available && dmi_name_in_serial("VMware") && 251 __vmware_platform()) 252 return 1; 253 254 return 0; 255 } 256 257 /* Checks if hypervisor supports x2apic without VT-D interrupt remapping. */ 258 static bool __init vmware_legacy_x2apic_available(void) 259 { 260 uint32_t eax, ebx, ecx, edx; 261 VMWARE_CMD(GETVCPU_INFO, eax, ebx, ecx, edx); 262 return (eax & (1 << VMWARE_CMD_VCPU_RESERVED)) == 0 && 263 (eax & (1 << VMWARE_CMD_LEGACY_X2APIC)) != 0; 264 } 265 266 const __initconst struct hypervisor_x86 x86_hyper_vmware = { 267 .name = "VMware", 268 .detect = vmware_platform, 269 .type = X86_HYPER_VMWARE, 270 .init.init_platform = vmware_platform_setup, 271 .init.x2apic_available = vmware_legacy_x2apic_available, 272 }; 273