arch/x86/kernel/cpu/vmware.c

   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 <linux/clocksource.h>
  28 #include <asm/div64.h>
  29 #include <asm/x86_init.h>
  30 #include <asm/hypervisor.h>
  31 #include <asm/timer.h>
  32 #include <asm/apic.h>
  33 #include <asm/timer.h>
  34
  35 #undef pr_fmt
  36 #define pr_fmt(fmt)     "vmware: " fmt
  37
  38 #define CPUID_VMWARE_INFO_LEAF  0x40000000
  39 #define VMWARE_HYPERVISOR_MAGIC 0x564D5868
  40 #define VMWARE_HYPERVISOR_PORT  0x5658
  41
  42 #define VMWARE_PORT_CMD_GETVERSION      10
  43 #define VMWARE_PORT_CMD_GETHZ           45
  44 #define VMWARE_PORT_CMD_GETVCPU_INFO    68
  45 #define VMWARE_PORT_CMD_LEGACY_X2APIC   3
  46 #define VMWARE_PORT_CMD_VCPU_RESERVED   31
  47
  48 #define VMWARE_PORT(cmd, eax, ebx, ecx, edx)                            \
  49         __asm__("inl (%%dx)" :                                          \
  50                         "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) :    \
  51                         "0"(VMWARE_HYPERVISOR_MAGIC),                   \
  52                         "1"(VMWARE_PORT_CMD_##cmd),                     \
  53                         "2"(VMWARE_HYPERVISOR_PORT), "3"(UINT_MAX) :    \
  54                         "memory");
  55
  56 static unsigned long vmware_tsc_khz __ro_after_init;
  57
  58 static inline int __vmware_platform(void)
  59 {
  60         uint32_t eax, ebx, ecx, edx;
  61         VMWARE_PORT(GETVERSION, eax, ebx, ecx, edx);
  62         return eax != (uint32_t)-1 && ebx == VMWARE_HYPERVISOR_MAGIC;
  63 }
  64
  65 static unsigned long vmware_get_tsc_khz(void)
  66 {
  67         return vmware_tsc_khz;
  68 }
  69
  70 #ifdef CONFIG_PARAVIRT
  71 static struct cyc2ns_data vmware_cyc2ns __ro_after_init;
  72 static int vmw_sched_clock __initdata = 1;
  73
  74 static __init int setup_vmw_sched_clock(char *s)
  75 {
  76         vmw_sched_clock = 0;
  77         return 0;
  78 }
  79 early_param("no-vmw-sched-clock", setup_vmw_sched_clock);
  80
  81 static unsigned long long vmware_sched_clock(void)
  82 {
  83         unsigned long long ns;
  84
  85         ns = mul_u64_u32_shr(rdtsc(), vmware_cyc2ns.cyc2ns_mul,
  86                              vmware_cyc2ns.cyc2ns_shift);
  87         ns -= vmware_cyc2ns.cyc2ns_offset;
  88         return ns;
  89 }
  90
  91 static void __init vmware_sched_clock_setup(void)
  92 {
  93         struct cyc2ns_data *d = &vmware_cyc2ns;
  94         unsigned long long tsc_now = rdtsc();
  95
  96         clocks_calc_mult_shift(&d->cyc2ns_mul, &d->cyc2ns_shift,
  97                                vmware_tsc_khz, NSEC_PER_MSEC, 0);
  98         d->cyc2ns_offset = mul_u64_u32_shr(tsc_now, d->cyc2ns_mul,
  99                                            d->cyc2ns_shift);
 100
 101         pv_time_ops.sched_clock = vmware_sched_clock;
 102         pr_info("using sched offset of %llu ns\n", d->cyc2ns_offset);
 103 }
 104
 105 static void __init vmware_paravirt_ops_setup(void)
 106 {
 107         pv_info.name = "VMware hypervisor";
 108         pv_cpu_ops.io_delay = paravirt_nop;
 109
 110         if (vmware_tsc_khz && vmw_sched_clock)
 111                 vmware_sched_clock_setup();
 112 }
 113 #else
 114 #define vmware_paravirt_ops_setup() do {} while (0)
 115 #endif
 116
 117 static void __init vmware_platform_setup(void)
 118 {
 119         uint32_t eax, ebx, ecx, edx;
 120         uint64_t lpj, tsc_khz;
 121
 122         VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
 123
 124         if (ebx != UINT_MAX) {
 125                 lpj = tsc_khz = eax | (((uint64_t)ebx) << 32);
 126                 do_div(tsc_khz, 1000);
 127                 WARN_ON(tsc_khz >> 32);
 128                 pr_info("TSC freq read from hypervisor : %lu.%03lu MHz\n",
 129                         (unsigned long) tsc_khz / 1000,
 130                         (unsigned long) tsc_khz % 1000);
 131
 132                 if (!preset_lpj) {
 133                         do_div(lpj, HZ);
 134                         preset_lpj = lpj;
 135                 }
 136
 137                 vmware_tsc_khz = tsc_khz;
 138                 x86_platform.calibrate_tsc = vmware_get_tsc_khz;
 139                 x86_platform.calibrate_cpu = vmware_get_tsc_khz;
 140
 141 #ifdef CONFIG_X86_LOCAL_APIC
 142                 /* Skip lapic calibration since we know the bus frequency. */
 143                 lapic_timer_frequency = ecx / HZ;
 144                 pr_info("Host bus clock speed read from hypervisor : %u Hz\n",
 145                         ecx);
 146 #endif
 147         } else {
 148                 pr_warn("Failed to get TSC freq from the hypervisor\n");
 149         }
 150
 151         vmware_paravirt_ops_setup();
 152
 153 #ifdef CONFIG_X86_IO_APIC
 154         no_timer_check = 1;
 155 #endif
 156 }
 157
 158 /*
 159  * While checking the dmi string information, just checking the product
 160  * serial key should be enough, as this will always have a VMware
 161  * specific string when running under VMware hypervisor.
 162  */
 163 static uint32_t __init vmware_platform(void)
 164 {
 165         if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
 166                 unsigned int eax;
 167                 unsigned int hyper_vendor_id[3];
 168
 169                 cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &hyper_vendor_id[0],
 170                       &hyper_vendor_id[1], &hyper_vendor_id[2]);
 171                 if (!memcmp(hyper_vendor_id, "VMwareVMware", 12))
 172                         return CPUID_VMWARE_INFO_LEAF;
 173         } else if (dmi_available && dmi_name_in_serial("VMware") &&
 174                    __vmware_platform())
 175                 return 1;
 176
 177         return 0;
 178 }
 179
 180 /*
 181  * VMware hypervisor takes care of exporting a reliable TSC to the guest.
 182  * Still, due to timing difference when running on virtual cpus, the TSC can
 183  * be marked as unstable in some cases. For example, the TSC sync check at
 184  * bootup can fail due to a marginal offset between vcpus' TSCs (though the
 185  * TSCs do not drift from each other).  Also, the ACPI PM timer clocksource
 186  * is not suitable as a watchdog when running on a hypervisor because the
 187  * kernel may miss a wrap of the counter if the vcpu is descheduled for a
 188  * long time. To skip these checks at runtime we set these capability bits,
 189  * so that the kernel could just trust the hypervisor with providing a
 190  * reliable virtual TSC that is suitable for timekeeping.
 191  */
 192 static void vmware_set_cpu_features(struct cpuinfo_x86 *c)
 193 {
 194         set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
 195         set_cpu_cap(c, X86_FEATURE_TSC_RELIABLE);
 196 }
 197
 198 /* Checks if hypervisor supports x2apic without VT-D interrupt remapping. */
 199 static bool __init vmware_legacy_x2apic_available(void)
 200 {
 201         uint32_t eax, ebx, ecx, edx;
 202         VMWARE_PORT(GETVCPU_INFO, eax, ebx, ecx, edx);
 203         return (eax & (1 << VMWARE_PORT_CMD_VCPU_RESERVED)) == 0 &&
 204                (eax & (1 << VMWARE_PORT_CMD_LEGACY_X2APIC)) != 0;
 205 }
 206
 207 const __refconst struct hypervisor_x86 x86_hyper_vmware = {
 208         .name                   = "VMware",
 209         .detect                 = vmware_platform,
 210         .set_cpu_features       = vmware_set_cpu_features,
 211         .init_platform          = vmware_platform_setup,
 212         .x2apic_available       = vmware_legacy_x2apic_available,
 213 };
 214 EXPORT_SYMBOL(x86_hyper_vmware);