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