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