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; 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 return tsc_hz; 66 } 67 68 static void __init vmware_platform_setup(void) 69 { 70 uint32_t eax, ebx, ecx, edx; 71 72 VMWARE_PORT(GETHZ, eax, ebx, ecx, edx); 73 74 if (ebx != UINT_MAX) 75 x86_platform.calibrate_tsc = vmware_get_tsc_khz; 76 else 77 printk(KERN_WARNING 78 "Failed to get TSC freq from the hypervisor\n"); 79 } 80 81 /* 82 * While checking the dmi string infomation, just checking the product 83 * serial key should be enough, as this will always have a VMware 84 * specific string when running under VMware hypervisor. 85 */ 86 static bool __init vmware_platform(void) 87 { 88 if (cpu_has_hypervisor) { 89 unsigned int eax; 90 unsigned int hyper_vendor_id[3]; 91 92 cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &hyper_vendor_id[0], 93 &hyper_vendor_id[1], &hyper_vendor_id[2]); 94 if (!memcmp(hyper_vendor_id, "VMwareVMware", 12)) 95 return true; 96 } else if (dmi_available && dmi_name_in_serial("VMware") && 97 __vmware_platform()) 98 return true; 99 100 return false; 101 } 102 103 /* 104 * VMware hypervisor takes care of exporting a reliable TSC to the guest. 105 * Still, due to timing difference when running on virtual cpus, the TSC can 106 * be marked as unstable in some cases. For example, the TSC sync check at 107 * bootup can fail due to a marginal offset between vcpus' TSCs (though the 108 * TSCs do not drift from each other). Also, the ACPI PM timer clocksource 109 * is not suitable as a watchdog when running on a hypervisor because the 110 * kernel may miss a wrap of the counter if the vcpu is descheduled for a 111 * long time. To skip these checks at runtime we set these capability bits, 112 * so that the kernel could just trust the hypervisor with providing a 113 * reliable virtual TSC that is suitable for timekeeping. 114 */ 115 static void __cpuinit vmware_set_cpu_features(struct cpuinfo_x86 *c) 116 { 117 set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC); 118 set_cpu_cap(c, X86_FEATURE_TSC_RELIABLE); 119 } 120 121 const __refconst struct hypervisor_x86 x86_hyper_vmware = { 122 .name = "VMware", 123 .detect = vmware_platform, 124 .set_cpu_features = vmware_set_cpu_features, 125 .init_platform = vmware_platform_setup, 126 }; 127 EXPORT_SYMBOL(x86_hyper_vmware); 128