2 * VMware Detection code.
4 * Copyright (C) 2008, VMware, Inc.
5 * Author : Alok N Kataria <akataria@vmware.com>
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.
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
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.
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>
33 #include <asm/timer.h>
36 #define pr_fmt(fmt) "vmware: " fmt
38 #define CPUID_VMWARE_INFO_LEAF 0x40000000
39 #define VMWARE_HYPERVISOR_MAGIC 0x564D5868
40 #define VMWARE_HYPERVISOR_PORT 0x5658
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
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) : \
56 static unsigned long vmware_tsc_khz __ro_after_init;
58 static inline int __vmware_platform(void)
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;
65 static unsigned long vmware_get_tsc_khz(void)
67 return vmware_tsc_khz;
70 #ifdef CONFIG_PARAVIRT
71 static struct cyc2ns_data vmware_cyc2ns __ro_after_init;
72 static int vmw_sched_clock __initdata = 1;
74 static __init int setup_vmw_sched_clock(char *s)
79 early_param("no-vmw-sched-clock", setup_vmw_sched_clock);
81 static unsigned long long vmware_sched_clock(void)
83 unsigned long long ns;
85 ns = mul_u64_u32_shr(rdtsc(), vmware_cyc2ns.cyc2ns_mul,
86 vmware_cyc2ns.cyc2ns_shift);
87 ns -= vmware_cyc2ns.cyc2ns_offset;
91 static void __init vmware_sched_clock_setup(void)
93 struct cyc2ns_data *d = &vmware_cyc2ns;
94 unsigned long long tsc_now = rdtsc();
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,
101 pv_time_ops.sched_clock = vmware_sched_clock;
102 pr_info("using sched offset of %llu ns\n", d->cyc2ns_offset);
105 static void __init vmware_paravirt_ops_setup(void)
107 pv_info.name = "VMware hypervisor";
108 pv_cpu_ops.io_delay = paravirt_nop;
110 if (vmware_tsc_khz && vmw_sched_clock)
111 vmware_sched_clock_setup();
114 #define vmware_paravirt_ops_setup() do {} while (0)
117 static void __init vmware_platform_setup(void)
119 uint32_t eax, ebx, ecx, edx;
120 uint64_t lpj, tsc_khz;
122 VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
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);
137 vmware_tsc_khz = tsc_khz;
138 x86_platform.calibrate_tsc = vmware_get_tsc_khz;
139 x86_platform.calibrate_cpu = vmware_get_tsc_khz;
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",
148 pr_warn("Failed to get TSC freq from the hypervisor\n");
151 vmware_paravirt_ops_setup();
153 #ifdef CONFIG_X86_IO_APIC
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.
163 static uint32_t __init vmware_platform(void)
165 if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
167 unsigned int hyper_vendor_id[3];
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") &&
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.
192 static void vmware_set_cpu_features(struct cpuinfo_x86 *c)
194 set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
195 set_cpu_cap(c, X86_FEATURE_TSC_RELIABLE);
198 /* Checks if hypervisor supports x2apic without VT-D interrupt remapping. */
199 static bool __init vmware_legacy_x2apic_available(void)
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;
207 const __refconst struct hypervisor_x86 x86_hyper_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,
214 EXPORT_SYMBOL(x86_hyper_vmware);