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 34 #undef pr_fmt 35 #define pr_fmt(fmt) "vmware: " fmt 36 37 #define CPUID_VMWARE_INFO_LEAF 0x40000000 38 #define VMWARE_HYPERVISOR_MAGIC 0x564D5868 39 #define VMWARE_HYPERVISOR_PORT 0x5658 40 41 #define VMWARE_PORT_CMD_GETVERSION 10 42 #define VMWARE_PORT_CMD_GETHZ 45 43 #define VMWARE_PORT_CMD_GETVCPU_INFO 68 44 #define VMWARE_PORT_CMD_LEGACY_X2APIC 3 45 #define VMWARE_PORT_CMD_VCPU_RESERVED 31 46 47 #define VMWARE_PORT(cmd, eax, ebx, ecx, edx) \ 48 __asm__("inl (%%dx)" : \ 49 "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) : \ 50 "0"(VMWARE_HYPERVISOR_MAGIC), \ 51 "1"(VMWARE_PORT_CMD_##cmd), \ 52 "2"(VMWARE_HYPERVISOR_PORT), "3"(UINT_MAX) : \ 53 "memory"); 54 55 static unsigned long vmware_tsc_khz __ro_after_init; 56 57 static inline int __vmware_platform(void) 58 { 59 uint32_t eax, ebx, ecx, edx; 60 VMWARE_PORT(GETVERSION, eax, ebx, ecx, edx); 61 return eax != (uint32_t)-1 && ebx == VMWARE_HYPERVISOR_MAGIC; 62 } 63 64 static unsigned long vmware_get_tsc_khz(void) 65 { 66 return vmware_tsc_khz; 67 } 68 69 #ifdef CONFIG_PARAVIRT 70 static struct cyc2ns_data vmware_cyc2ns __ro_after_init; 71 static int vmw_sched_clock __initdata = 1; 72 73 static __init int setup_vmw_sched_clock(char *s) 74 { 75 vmw_sched_clock = 0; 76 return 0; 77 } 78 early_param("no-vmw-sched-clock", setup_vmw_sched_clock); 79 80 static unsigned long long notrace vmware_sched_clock(void) 81 { 82 unsigned long long ns; 83 84 ns = mul_u64_u32_shr(rdtsc(), vmware_cyc2ns.cyc2ns_mul, 85 vmware_cyc2ns.cyc2ns_shift); 86 ns -= vmware_cyc2ns.cyc2ns_offset; 87 return ns; 88 } 89 90 static void __init vmware_sched_clock_setup(void) 91 { 92 struct cyc2ns_data *d = &vmware_cyc2ns; 93 unsigned long long tsc_now = rdtsc(); 94 95 clocks_calc_mult_shift(&d->cyc2ns_mul, &d->cyc2ns_shift, 96 vmware_tsc_khz, NSEC_PER_MSEC, 0); 97 d->cyc2ns_offset = mul_u64_u32_shr(tsc_now, d->cyc2ns_mul, 98 d->cyc2ns_shift); 99 100 pv_ops.time.sched_clock = vmware_sched_clock; 101 pr_info("using sched offset of %llu ns\n", d->cyc2ns_offset); 102 } 103 104 static void __init vmware_paravirt_ops_setup(void) 105 { 106 pv_info.name = "VMware hypervisor"; 107 pv_ops.cpu.io_delay = paravirt_nop; 108 109 if (vmware_tsc_khz && vmw_sched_clock) 110 vmware_sched_clock_setup(); 111 } 112 #else 113 #define vmware_paravirt_ops_setup() do {} while (0) 114 #endif 115 116 /* 117 * VMware hypervisor takes care of exporting a reliable TSC to the guest. 118 * Still, due to timing difference when running on virtual cpus, the TSC can 119 * be marked as unstable in some cases. For example, the TSC sync check at 120 * bootup can fail due to a marginal offset between vcpus' TSCs (though the 121 * TSCs do not drift from each other). Also, the ACPI PM timer clocksource 122 * is not suitable as a watchdog when running on a hypervisor because the 123 * kernel may miss a wrap of the counter if the vcpu is descheduled for a 124 * long time. To skip these checks at runtime we set these capability bits, 125 * so that the kernel could just trust the hypervisor with providing a 126 * reliable virtual TSC that is suitable for timekeeping. 127 */ 128 static void __init vmware_set_capabilities(void) 129 { 130 setup_force_cpu_cap(X86_FEATURE_CONSTANT_TSC); 131 setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE); 132 } 133 134 static void __init vmware_platform_setup(void) 135 { 136 uint32_t eax, ebx, ecx, edx; 137 uint64_t lpj, tsc_khz; 138 139 VMWARE_PORT(GETHZ, eax, ebx, ecx, edx); 140 141 if (ebx != UINT_MAX) { 142 lpj = tsc_khz = eax | (((uint64_t)ebx) << 32); 143 do_div(tsc_khz, 1000); 144 WARN_ON(tsc_khz >> 32); 145 pr_info("TSC freq read from hypervisor : %lu.%03lu MHz\n", 146 (unsigned long) tsc_khz / 1000, 147 (unsigned long) tsc_khz % 1000); 148 149 if (!preset_lpj) { 150 do_div(lpj, HZ); 151 preset_lpj = lpj; 152 } 153 154 vmware_tsc_khz = tsc_khz; 155 x86_platform.calibrate_tsc = vmware_get_tsc_khz; 156 x86_platform.calibrate_cpu = vmware_get_tsc_khz; 157 158 #ifdef CONFIG_X86_LOCAL_APIC 159 /* Skip lapic calibration since we know the bus frequency. */ 160 lapic_timer_period = ecx / HZ; 161 pr_info("Host bus clock speed read from hypervisor : %u Hz\n", 162 ecx); 163 #endif 164 } else { 165 pr_warn("Failed to get TSC freq from the hypervisor\n"); 166 } 167 168 vmware_paravirt_ops_setup(); 169 170 #ifdef CONFIG_X86_IO_APIC 171 no_timer_check = 1; 172 #endif 173 174 vmware_set_capabilities(); 175 } 176 177 /* 178 * While checking the dmi string information, just checking the product 179 * serial key should be enough, as this will always have a VMware 180 * specific string when running under VMware hypervisor. 181 */ 182 static uint32_t __init vmware_platform(void) 183 { 184 if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) { 185 unsigned int eax; 186 unsigned int hyper_vendor_id[3]; 187 188 cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &hyper_vendor_id[0], 189 &hyper_vendor_id[1], &hyper_vendor_id[2]); 190 if (!memcmp(hyper_vendor_id, "VMwareVMware", 12)) 191 return CPUID_VMWARE_INFO_LEAF; 192 } else if (dmi_available && dmi_name_in_serial("VMware") && 193 __vmware_platform()) 194 return 1; 195 196 return 0; 197 } 198 199 /* Checks if hypervisor supports x2apic without VT-D interrupt remapping. */ 200 static bool __init vmware_legacy_x2apic_available(void) 201 { 202 uint32_t eax, ebx, ecx, edx; 203 VMWARE_PORT(GETVCPU_INFO, eax, ebx, ecx, edx); 204 return (eax & (1 << VMWARE_PORT_CMD_VCPU_RESERVED)) == 0 && 205 (eax & (1 << VMWARE_PORT_CMD_LEGACY_X2APIC)) != 0; 206 } 207 208 const __initconst struct hypervisor_x86 x86_hyper_vmware = { 209 .name = "VMware", 210 .detect = vmware_platform, 211 .type = X86_HYPER_VMWARE, 212 .init.init_platform = vmware_platform_setup, 213 .init.x2apic_available = vmware_legacy_x2apic_available, 214 }; 215