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 <asm/div64.h> 26 #include <asm/vmware.h> 27 #include <asm/x86_init.h> 28 29 #define CPUID_VMWARE_INFO_LEAF 0x40000000 30 #define VMWARE_HYPERVISOR_MAGIC 0x564D5868 31 #define VMWARE_HYPERVISOR_PORT 0x5658 32 33 #define VMWARE_PORT_CMD_GETVERSION 10 34 #define VMWARE_PORT_CMD_GETHZ 45 35 36 #define VMWARE_PORT(cmd, eax, ebx, ecx, edx) \ 37 __asm__("inl (%%dx)" : \ 38 "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) : \ 39 "0"(VMWARE_HYPERVISOR_MAGIC), \ 40 "1"(VMWARE_PORT_CMD_##cmd), \ 41 "2"(VMWARE_HYPERVISOR_PORT), "3"(UINT_MAX) : \ 42 "memory"); 43 44 static inline int __vmware_platform(void) 45 { 46 uint32_t eax, ebx, ecx, edx; 47 VMWARE_PORT(GETVERSION, eax, ebx, ecx, edx); 48 return eax != (uint32_t)-1 && ebx == VMWARE_HYPERVISOR_MAGIC; 49 } 50 51 static unsigned long vmware_get_tsc_khz(void) 52 { 53 uint64_t tsc_hz; 54 uint32_t eax, ebx, ecx, edx; 55 56 VMWARE_PORT(GETHZ, eax, ebx, ecx, edx); 57 58 tsc_hz = eax | (((uint64_t)ebx) << 32); 59 do_div(tsc_hz, 1000); 60 BUG_ON(tsc_hz >> 32); 61 printk(KERN_INFO "TSC freq read from hypervisor : %lu.%03lu MHz\n", 62 (unsigned long) tsc_hz / 1000, 63 (unsigned long) tsc_hz % 1000); 64 return tsc_hz; 65 } 66 67 void __init vmware_platform_setup(void) 68 { 69 uint32_t eax, ebx, ecx, edx; 70 71 VMWARE_PORT(GETHZ, eax, ebx, ecx, edx); 72 73 if (ebx != UINT_MAX) 74 x86_platform.calibrate_tsc = vmware_get_tsc_khz; 75 else 76 printk(KERN_WARNING 77 "Failed to get TSC freq from the hypervisor\n"); 78 } 79 80 /* 81 * While checking the dmi string infomation, just checking the product 82 * serial key should be enough, as this will always have a VMware 83 * specific string when running under VMware hypervisor. 84 */ 85 int vmware_platform(void) 86 { 87 if (cpu_has_hypervisor) { 88 unsigned int eax, ebx, ecx, edx; 89 char hyper_vendor_id[13]; 90 91 cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &ebx, &ecx, &edx); 92 memcpy(hyper_vendor_id + 0, &ebx, 4); 93 memcpy(hyper_vendor_id + 4, &ecx, 4); 94 memcpy(hyper_vendor_id + 8, &edx, 4); 95 hyper_vendor_id[12] = '\0'; 96 if (!strcmp(hyper_vendor_id, "VMwareVMware")) 97 return 1; 98 } else if (dmi_available && dmi_name_in_serial("VMware") && 99 __vmware_platform()) 100 return 1; 101 102 return 0; 103 } 104 105 /* 106 * VMware hypervisor takes care of exporting a reliable TSC to the guest. 107 * Still, due to timing difference when running on virtual cpus, the TSC can 108 * be marked as unstable in some cases. For example, the TSC sync check at 109 * bootup can fail due to a marginal offset between vcpus' TSCs (though the 110 * TSCs do not drift from each other). Also, the ACPI PM timer clocksource 111 * is not suitable as a watchdog when running on a hypervisor because the 112 * kernel may miss a wrap of the counter if the vcpu is descheduled for a 113 * long time. To skip these checks at runtime we set these capability bits, 114 * so that the kernel could just trust the hypervisor with providing a 115 * reliable virtual TSC that is suitable for timekeeping. 116 */ 117 void __cpuinit vmware_set_feature_bits(struct cpuinfo_x86 *c) 118 { 119 set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC); 120 set_cpu_cap(c, X86_FEATURE_TSC_RELIABLE); 121 } 122