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
  34 #undef pr_fmt
  35 #define pr_fmt(fmt)     "vmware: " fmt
  36
  37 #define CPUID_VMWARE_INFO_LEAF  0x40000000
  38 #define VMWARE_HYPERVISOR_MAGIC 0x564D5868
  39 #define VMWARE_HYPERVISOR_PORT  0x5658
  40
  41 #define VMWARE_PORT_CMD_GETVERSION      10
  42 #define VMWARE_PORT_CMD_GETHZ           45
  43 #define VMWARE_PORT_CMD_GETVCPU_INFO    68
  44 #define VMWARE_PORT_CMD_LEGACY_X2APIC   3
  45 #define VMWARE_PORT_CMD_VCPU_RESERVED   31
  46
  47 #define VMWARE_PORT(cmd, eax, ebx, ecx, edx)                            \
  48         __asm__("inl (%%dx)" :                                          \
  49                         "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) :    \
  50                         "0"(VMWARE_HYPERVISOR_MAGIC),                   \
  51                         "1"(VMWARE_PORT_CMD_##cmd),                     \
  52                         "2"(VMWARE_HYPERVISOR_PORT), "3"(UINT_MAX) :    \
  53                         "memory");
  54
  55 static unsigned long vmware_tsc_khz __ro_after_init;
  56
  57 static inline int __vmware_platform(void)
  58 {
  59         uint32_t eax, ebx, ecx, edx;
  60         VMWARE_PORT(GETVERSION, eax, ebx, ecx, edx);
  61         return eax != (uint32_t)-1 && ebx == VMWARE_HYPERVISOR_MAGIC;
  62 }
  63
  64 static unsigned long vmware_get_tsc_khz(void)
  65 {
  66         return vmware_tsc_khz;
  67 }
  68
  69 #ifdef CONFIG_PARAVIRT
  70 static struct cyc2ns_data vmware_cyc2ns __ro_after_init;
  71 static int vmw_sched_clock __initdata = 1;
  72
  73 static __init int setup_vmw_sched_clock(char *s)
  74 {
  75         vmw_sched_clock = 0;
  76         return 0;
  77 }
  78 early_param("no-vmw-sched-clock", setup_vmw_sched_clock);
  79
  80 static unsigned long long vmware_sched_clock(void)
  81 {
  82         unsigned long long ns;
  83
  84         ns = mul_u64_u32_shr(rdtsc(), vmware_cyc2ns.cyc2ns_mul,
  85                              vmware_cyc2ns.cyc2ns_shift);
  86         ns -= vmware_cyc2ns.cyc2ns_offset;
  87         return ns;
  88 }
  89
  90 static void __init vmware_sched_clock_setup(void)
  91 {
  92         struct cyc2ns_data *d = &vmware_cyc2ns;
  93         unsigned long long tsc_now = rdtsc();
  94
  95         clocks_calc_mult_shift(&d->cyc2ns_mul, &d->cyc2ns_shift,
  96                                vmware_tsc_khz, NSEC_PER_MSEC, 0);
  97         d->cyc2ns_offset = mul_u64_u32_shr(tsc_now, d->cyc2ns_mul,
  98                                            d->cyc2ns_shift);
  99
 100         pv_ops.time.sched_clock = vmware_sched_clock;
 101         pr_info("using sched offset of %llu ns\n", d->cyc2ns_offset);
 102 }
 103
 104 static void __init vmware_paravirt_ops_setup(void)
 105 {
 106         pv_info.name = "VMware hypervisor";
 107         pv_ops.cpu.io_delay = paravirt_nop;
 108
 109         if (vmware_tsc_khz && vmw_sched_clock)
 110                 vmware_sched_clock_setup();
 111 }
 112 #else
 113 #define vmware_paravirt_ops_setup() do {} while (0)
 114 #endif
 115
 116 /*
 117  * VMware hypervisor takes care of exporting a reliable TSC to the guest.
 118  * Still, due to timing difference when running on virtual cpus, the TSC can
 119  * be marked as unstable in some cases. For example, the TSC sync check at
 120  * bootup can fail due to a marginal offset between vcpus' TSCs (though the
 121  * TSCs do not drift from each other).  Also, the ACPI PM timer clocksource
 122  * is not suitable as a watchdog when running on a hypervisor because the
 123  * kernel may miss a wrap of the counter if the vcpu is descheduled for a
 124  * long time. To skip these checks at runtime we set these capability bits,
 125  * so that the kernel could just trust the hypervisor with providing a
 126  * reliable virtual TSC that is suitable for timekeeping.
 127  */
 128 static void __init vmware_set_capabilities(void)
 129 {
 130         setup_force_cpu_cap(X86_FEATURE_CONSTANT_TSC);
 131         setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
 132 }
 133
 134 static void __init vmware_platform_setup(void)
 135 {
 136         uint32_t eax, ebx, ecx, edx;
 137         uint64_t lpj, tsc_khz;
 138
 139         VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
 140
 141         if (ebx != UINT_MAX) {
 142                 lpj = tsc_khz = eax | (((uint64_t)ebx) << 32);
 143                 do_div(tsc_khz, 1000);
 144                 WARN_ON(tsc_khz >> 32);
 145                 pr_info("TSC freq read from hypervisor : %lu.%03lu MHz\n",
 146                         (unsigned long) tsc_khz / 1000,
 147                         (unsigned long) tsc_khz % 1000);
 148
 149                 if (!preset_lpj) {
 150                         do_div(lpj, HZ);
 151                         preset_lpj = lpj;
 152                 }
 153
 154                 vmware_tsc_khz = tsc_khz;
 155                 x86_platform.calibrate_tsc = vmware_get_tsc_khz;
 156                 x86_platform.calibrate_cpu = vmware_get_tsc_khz;
 157
 158 #ifdef CONFIG_X86_LOCAL_APIC
 159                 /* Skip lapic calibration since we know the bus frequency. */
 160                 lapic_timer_frequency = ecx / HZ;
 161                 pr_info("Host bus clock speed read from hypervisor : %u Hz\n",
 162                         ecx);
 163 #endif
 164         } else {
 165                 pr_warn("Failed to get TSC freq from the hypervisor\n");
 166         }
 167
 168         vmware_paravirt_ops_setup();
 169
 170 #ifdef CONFIG_X86_IO_APIC
 171         no_timer_check = 1;
 172 #endif
 173
 174         vmware_set_capabilities();
 175 }
 176
 177 /*
 178  * While checking the dmi string information, just checking the product
 179  * serial key should be enough, as this will always have a VMware
 180  * specific string when running under VMware hypervisor.
 181  */
 182 static uint32_t __init vmware_platform(void)
 183 {
 184         if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
 185                 unsigned int eax;
 186                 unsigned int hyper_vendor_id[3];
 187
 188                 cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &hyper_vendor_id[0],
 189                       &hyper_vendor_id[1], &hyper_vendor_id[2]);
 190                 if (!memcmp(hyper_vendor_id, "VMwareVMware", 12))
 191                         return CPUID_VMWARE_INFO_LEAF;
 192         } else if (dmi_available && dmi_name_in_serial("VMware") &&
 193                    __vmware_platform())
 194                 return 1;
 195
 196         return 0;
 197 }
 198
 199 /* Checks if hypervisor supports x2apic without VT-D interrupt remapping. */
 200 static bool __init vmware_legacy_x2apic_available(void)
 201 {
 202         uint32_t eax, ebx, ecx, edx;
 203         VMWARE_PORT(GETVCPU_INFO, eax, ebx, ecx, edx);
 204         return (eax & (1 << VMWARE_PORT_CMD_VCPU_RESERVED)) == 0 &&
 205                (eax & (1 << VMWARE_PORT_CMD_LEGACY_X2APIC)) != 0;
 206 }
 207
 208 const __initconst struct hypervisor_x86 x86_hyper_vmware = {
 209         .name                   = "VMware",
 210         .detect                 = vmware_platform,
 211         .type                   = X86_HYPER_VMWARE,
 212         .init.init_platform     = vmware_platform_setup,
 213         .init.x2apic_available  = vmware_legacy_x2apic_available,
 214 };