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/module.h> 26 #include <asm/div64.h> 27 #include <asm/x86_init.h> 28 #include <asm/hypervisor.h> 29 30 #define CPUID_VMWARE_INFO_LEAF 0x40000000 31 #define VMWARE_HYPERVISOR_MAGIC 0x564D5868 32 #define VMWARE_HYPERVISOR_PORT 0x5658 33 34 #define VMWARE_PORT_CMD_GETVERSION 10 35 #define VMWARE_PORT_CMD_GETHZ 45 36 37 #define VMWARE_PORT(cmd, eax, ebx, ecx, edx) \ 38 __asm__("inl (%%dx)" : \ 39 "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) : \ 40 "0"(VMWARE_HYPERVISOR_MAGIC), \ 41 "1"(VMWARE_PORT_CMD_##cmd), \ 42 "2"(VMWARE_HYPERVISOR_PORT), "3"(UINT_MAX) : \ 43 "memory"); 44 45 static inline int __vmware_platform(void) 46 { 47 uint32_t eax, ebx, ecx, edx; 48 VMWARE_PORT(GETVERSION, eax, ebx, ecx, edx); 49 return eax != (uint32_t)-1 && ebx == VMWARE_HYPERVISOR_MAGIC; 50 } 51 52 static unsigned long vmware_get_tsc_khz(void) 53 { 54 uint64_t tsc_hz, lpj; 55 uint32_t eax, ebx, ecx, edx; 56 57 VMWARE_PORT(GETHZ, eax, ebx, ecx, edx); 58 59 tsc_hz = eax | (((uint64_t)ebx) << 32); 60 do_div(tsc_hz, 1000); 61 BUG_ON(tsc_hz >> 32); 62 printk(KERN_INFO "TSC freq read from hypervisor : %lu.%03lu MHz\n", 63 (unsigned long) tsc_hz / 1000, 64 (unsigned long) tsc_hz % 1000); 65 66 if (!preset_lpj) { 67 lpj = ((u64)tsc_hz * 1000); 68 do_div(lpj, HZ); 69 preset_lpj = lpj; 70 } 71 72 return tsc_hz; 73 } 74 75 static void __init vmware_platform_setup(void) 76 { 77 uint32_t eax, ebx, ecx, edx; 78 79 VMWARE_PORT(GETHZ, eax, ebx, ecx, edx); 80 81 if (ebx != UINT_MAX) 82 x86_platform.calibrate_tsc = vmware_get_tsc_khz; 83 else 84 printk(KERN_WARNING 85 "Failed to get TSC freq from the hypervisor\n"); 86 } 87 88 /* 89 * While checking the dmi string infomation, just checking the product 90 * serial key should be enough, as this will always have a VMware 91 * specific string when running under VMware hypervisor. 92 */ 93 static bool __init vmware_platform(void) 94 { 95 if (cpu_has_hypervisor) { 96 unsigned int eax; 97 unsigned int hyper_vendor_id[3]; 98 99 cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &hyper_vendor_id[0], 100 &hyper_vendor_id[1], &hyper_vendor_id[2]); 101 if (!memcmp(hyper_vendor_id, "VMwareVMware", 12)) 102 return true; 103 } else if (dmi_available && dmi_name_in_serial("VMware") && 104 __vmware_platform()) 105 return true; 106 107 return false; 108 } 109 110 /* 111 * VMware hypervisor takes care of exporting a reliable TSC to the guest. 112 * Still, due to timing difference when running on virtual cpus, the TSC can 113 * be marked as unstable in some cases. For example, the TSC sync check at 114 * bootup can fail due to a marginal offset between vcpus' TSCs (though the 115 * TSCs do not drift from each other). Also, the ACPI PM timer clocksource 116 * is not suitable as a watchdog when running on a hypervisor because the 117 * kernel may miss a wrap of the counter if the vcpu is descheduled for a 118 * long time. To skip these checks at runtime we set these capability bits, 119 * so that the kernel could just trust the hypervisor with providing a 120 * reliable virtual TSC that is suitable for timekeeping. 121 */ 122 static void __cpuinit vmware_set_cpu_features(struct cpuinfo_x86 *c) 123 { 124 set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC); 125 set_cpu_cap(c, X86_FEATURE_TSC_RELIABLE); 126 } 127 128 const __refconst struct hypervisor_x86 x86_hyper_vmware = { 129 .name = "VMware", 130 .detect = vmware_platform, 131 .set_cpu_features = vmware_set_cpu_features, 132 .init_platform = vmware_platform_setup, 133 }; 134 EXPORT_SYMBOL(x86_hyper_vmware); 135