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 <asm/div64.h> 28 #include <asm/x86_init.h> 29 #include <asm/hypervisor.h> 30 #include <asm/apic.h> 31 32 #define CPUID_VMWARE_INFO_LEAF 0x40000000 33 #define VMWARE_HYPERVISOR_MAGIC 0x564D5868 34 #define VMWARE_HYPERVISOR_PORT 0x5658 35 36 #define VMWARE_PORT_CMD_GETVERSION 10 37 #define VMWARE_PORT_CMD_GETHZ 45 38 #define VMWARE_PORT_CMD_GETVCPU_INFO 68 39 #define VMWARE_PORT_CMD_LEGACY_X2APIC 3 40 #define VMWARE_PORT_CMD_VCPU_RESERVED 31 41 42 #define VMWARE_PORT(cmd, eax, ebx, ecx, edx) \ 43 __asm__("inl (%%dx)" : \ 44 "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) : \ 45 "0"(VMWARE_HYPERVISOR_MAGIC), \ 46 "1"(VMWARE_PORT_CMD_##cmd), \ 47 "2"(VMWARE_HYPERVISOR_PORT), "3"(UINT_MAX) : \ 48 "memory"); 49 50 static inline int __vmware_platform(void) 51 { 52 uint32_t eax, ebx, ecx, edx; 53 VMWARE_PORT(GETVERSION, eax, ebx, ecx, edx); 54 return eax != (uint32_t)-1 && ebx == VMWARE_HYPERVISOR_MAGIC; 55 } 56 57 static unsigned long vmware_get_tsc_khz(void) 58 { 59 uint64_t tsc_hz, lpj; 60 uint32_t eax, ebx, ecx, edx; 61 62 VMWARE_PORT(GETHZ, eax, ebx, ecx, edx); 63 64 tsc_hz = eax | (((uint64_t)ebx) << 32); 65 do_div(tsc_hz, 1000); 66 BUG_ON(tsc_hz >> 32); 67 pr_info("TSC freq read from hypervisor : %lu.%03lu MHz\n", 68 (unsigned long) tsc_hz / 1000, 69 (unsigned long) tsc_hz % 1000); 70 71 if (!preset_lpj) { 72 lpj = ((u64)tsc_hz * 1000); 73 do_div(lpj, HZ); 74 preset_lpj = lpj; 75 } 76 77 return tsc_hz; 78 } 79 80 static void __init vmware_platform_setup(void) 81 { 82 uint32_t eax, ebx, ecx, edx; 83 84 VMWARE_PORT(GETHZ, eax, ebx, ecx, edx); 85 86 if (ebx != UINT_MAX) { 87 x86_platform.calibrate_tsc = vmware_get_tsc_khz; 88 #ifdef CONFIG_X86_LOCAL_APIC 89 /* Skip lapic calibration since we know the bus frequency. */ 90 lapic_timer_frequency = ecx / HZ; 91 pr_info("Host bus clock speed read from hypervisor : %u Hz\n", 92 ecx); 93 #endif 94 } else { 95 pr_warn("Failed to get TSC freq from the hypervisor\n"); 96 } 97 } 98 99 /* 100 * While checking the dmi string information, just checking the product 101 * serial key should be enough, as this will always have a VMware 102 * specific string when running under VMware hypervisor. 103 */ 104 static uint32_t __init vmware_platform(void) 105 { 106 if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) { 107 unsigned int eax; 108 unsigned int hyper_vendor_id[3]; 109 110 cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &hyper_vendor_id[0], 111 &hyper_vendor_id[1], &hyper_vendor_id[2]); 112 if (!memcmp(hyper_vendor_id, "VMwareVMware", 12)) 113 return CPUID_VMWARE_INFO_LEAF; 114 } else if (dmi_available && dmi_name_in_serial("VMware") && 115 __vmware_platform()) 116 return 1; 117 118 return 0; 119 } 120 121 /* 122 * VMware hypervisor takes care of exporting a reliable TSC to the guest. 123 * Still, due to timing difference when running on virtual cpus, the TSC can 124 * be marked as unstable in some cases. For example, the TSC sync check at 125 * bootup can fail due to a marginal offset between vcpus' TSCs (though the 126 * TSCs do not drift from each other). Also, the ACPI PM timer clocksource 127 * is not suitable as a watchdog when running on a hypervisor because the 128 * kernel may miss a wrap of the counter if the vcpu is descheduled for a 129 * long time. To skip these checks at runtime we set these capability bits, 130 * so that the kernel could just trust the hypervisor with providing a 131 * reliable virtual TSC that is suitable for timekeeping. 132 */ 133 static void vmware_set_cpu_features(struct cpuinfo_x86 *c) 134 { 135 set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC); 136 set_cpu_cap(c, X86_FEATURE_TSC_RELIABLE); 137 } 138 139 /* Checks if hypervisor supports x2apic without VT-D interrupt remapping. */ 140 static bool __init vmware_legacy_x2apic_available(void) 141 { 142 uint32_t eax, ebx, ecx, edx; 143 VMWARE_PORT(GETVCPU_INFO, eax, ebx, ecx, edx); 144 return (eax & (1 << VMWARE_PORT_CMD_VCPU_RESERVED)) == 0 && 145 (eax & (1 << VMWARE_PORT_CMD_LEGACY_X2APIC)) != 0; 146 } 147 148 const __refconst struct hypervisor_x86 x86_hyper_vmware = { 149 .name = "VMware", 150 .detect = vmware_platform, 151 .set_cpu_features = vmware_set_cpu_features, 152 .init_platform = vmware_platform_setup, 153 .x2apic_available = vmware_legacy_x2apic_available, 154 }; 155 EXPORT_SYMBOL(x86_hyper_vmware); 156