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/timer.h> 34 35 #undef pr_fmt 36 #define pr_fmt(fmt) "vmware: " fmt 37 38 #define CPUID_VMWARE_INFO_LEAF 0x40000000 39 #define VMWARE_HYPERVISOR_MAGIC 0x564D5868 40 #define VMWARE_HYPERVISOR_PORT 0x5658 41 42 #define VMWARE_PORT_CMD_GETVERSION 10 43 #define VMWARE_PORT_CMD_GETHZ 45 44 #define VMWARE_PORT_CMD_GETVCPU_INFO 68 45 #define VMWARE_PORT_CMD_LEGACY_X2APIC 3 46 #define VMWARE_PORT_CMD_VCPU_RESERVED 31 47 48 #define VMWARE_PORT(cmd, eax, ebx, ecx, edx) \ 49 __asm__("inl (%%dx)" : \ 50 "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) : \ 51 "0"(VMWARE_HYPERVISOR_MAGIC), \ 52 "1"(VMWARE_PORT_CMD_##cmd), \ 53 "2"(VMWARE_HYPERVISOR_PORT), "3"(UINT_MAX) : \ 54 "memory"); 55 56 static unsigned long vmware_tsc_khz __ro_after_init; 57 58 static inline int __vmware_platform(void) 59 { 60 uint32_t eax, ebx, ecx, edx; 61 VMWARE_PORT(GETVERSION, eax, ebx, ecx, edx); 62 return eax != (uint32_t)-1 && ebx == VMWARE_HYPERVISOR_MAGIC; 63 } 64 65 static unsigned long vmware_get_tsc_khz(void) 66 { 67 return vmware_tsc_khz; 68 } 69 70 #ifdef CONFIG_PARAVIRT 71 static struct cyc2ns_data vmware_cyc2ns __ro_after_init; 72 static int vmw_sched_clock __initdata = 1; 73 74 static __init int setup_vmw_sched_clock(char *s) 75 { 76 vmw_sched_clock = 0; 77 return 0; 78 } 79 early_param("no-vmw-sched-clock", setup_vmw_sched_clock); 80 81 static unsigned long long vmware_sched_clock(void) 82 { 83 unsigned long long ns; 84 85 ns = mul_u64_u32_shr(rdtsc(), vmware_cyc2ns.cyc2ns_mul, 86 vmware_cyc2ns.cyc2ns_shift); 87 ns -= vmware_cyc2ns.cyc2ns_offset; 88 return ns; 89 } 90 91 static void __init vmware_sched_clock_setup(void) 92 { 93 struct cyc2ns_data *d = &vmware_cyc2ns; 94 unsigned long long tsc_now = rdtsc(); 95 96 clocks_calc_mult_shift(&d->cyc2ns_mul, &d->cyc2ns_shift, 97 vmware_tsc_khz, NSEC_PER_MSEC, 0); 98 d->cyc2ns_offset = mul_u64_u32_shr(tsc_now, d->cyc2ns_mul, 99 d->cyc2ns_shift); 100 101 pv_time_ops.sched_clock = vmware_sched_clock; 102 pr_info("using sched offset of %llu ns\n", d->cyc2ns_offset); 103 } 104 105 static void __init vmware_paravirt_ops_setup(void) 106 { 107 pv_info.name = "VMware hypervisor"; 108 pv_cpu_ops.io_delay = paravirt_nop; 109 110 if (vmware_tsc_khz && vmw_sched_clock) 111 vmware_sched_clock_setup(); 112 } 113 #else 114 #define vmware_paravirt_ops_setup() do {} while (0) 115 #endif 116 117 static void __init vmware_platform_setup(void) 118 { 119 uint32_t eax, ebx, ecx, edx; 120 uint64_t lpj, tsc_khz; 121 122 VMWARE_PORT(GETHZ, eax, ebx, ecx, edx); 123 124 if (ebx != UINT_MAX) { 125 lpj = tsc_khz = eax | (((uint64_t)ebx) << 32); 126 do_div(tsc_khz, 1000); 127 WARN_ON(tsc_khz >> 32); 128 pr_info("TSC freq read from hypervisor : %lu.%03lu MHz\n", 129 (unsigned long) tsc_khz / 1000, 130 (unsigned long) tsc_khz % 1000); 131 132 if (!preset_lpj) { 133 do_div(lpj, HZ); 134 preset_lpj = lpj; 135 } 136 137 vmware_tsc_khz = tsc_khz; 138 x86_platform.calibrate_tsc = vmware_get_tsc_khz; 139 x86_platform.calibrate_cpu = vmware_get_tsc_khz; 140 141 #ifdef CONFIG_X86_LOCAL_APIC 142 /* Skip lapic calibration since we know the bus frequency. */ 143 lapic_timer_frequency = ecx / HZ; 144 pr_info("Host bus clock speed read from hypervisor : %u Hz\n", 145 ecx); 146 #endif 147 } else { 148 pr_warn("Failed to get TSC freq from the hypervisor\n"); 149 } 150 151 vmware_paravirt_ops_setup(); 152 153 #ifdef CONFIG_X86_IO_APIC 154 no_timer_check = 1; 155 #endif 156 } 157 158 /* 159 * While checking the dmi string information, just checking the product 160 * serial key should be enough, as this will always have a VMware 161 * specific string when running under VMware hypervisor. 162 */ 163 static uint32_t __init vmware_platform(void) 164 { 165 if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) { 166 unsigned int eax; 167 unsigned int hyper_vendor_id[3]; 168 169 cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &hyper_vendor_id[0], 170 &hyper_vendor_id[1], &hyper_vendor_id[2]); 171 if (!memcmp(hyper_vendor_id, "VMwareVMware", 12)) 172 return CPUID_VMWARE_INFO_LEAF; 173 } else if (dmi_available && dmi_name_in_serial("VMware") && 174 __vmware_platform()) 175 return 1; 176 177 return 0; 178 } 179 180 /* 181 * VMware hypervisor takes care of exporting a reliable TSC to the guest. 182 * Still, due to timing difference when running on virtual cpus, the TSC can 183 * be marked as unstable in some cases. For example, the TSC sync check at 184 * bootup can fail due to a marginal offset between vcpus' TSCs (though the 185 * TSCs do not drift from each other). Also, the ACPI PM timer clocksource 186 * is not suitable as a watchdog when running on a hypervisor because the 187 * kernel may miss a wrap of the counter if the vcpu is descheduled for a 188 * long time. To skip these checks at runtime we set these capability bits, 189 * so that the kernel could just trust the hypervisor with providing a 190 * reliable virtual TSC that is suitable for timekeeping. 191 */ 192 static void vmware_set_cpu_features(struct cpuinfo_x86 *c) 193 { 194 set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC); 195 set_cpu_cap(c, X86_FEATURE_TSC_RELIABLE); 196 } 197 198 /* Checks if hypervisor supports x2apic without VT-D interrupt remapping. */ 199 static bool __init vmware_legacy_x2apic_available(void) 200 { 201 uint32_t eax, ebx, ecx, edx; 202 VMWARE_PORT(GETVCPU_INFO, eax, ebx, ecx, edx); 203 return (eax & (1 << VMWARE_PORT_CMD_VCPU_RESERVED)) == 0 && 204 (eax & (1 << VMWARE_PORT_CMD_LEGACY_X2APIC)) != 0; 205 } 206 207 const __refconst struct hypervisor_x86 x86_hyper_vmware = { 208 .name = "VMware", 209 .detect = vmware_platform, 210 .set_cpu_features = vmware_set_cpu_features, 211 .init_platform = vmware_platform_setup, 212 .x2apic_available = vmware_legacy_x2apic_available, 213 }; 214 EXPORT_SYMBOL(x86_hyper_vmware); 215