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>
35 #define pr_fmt(fmt) "vmware: " fmt
37 #define CPUID_VMWARE_INFO_LEAF 0x40000000
38 #define VMWARE_HYPERVISOR_MAGIC 0x564D5868
39 #define VMWARE_HYPERVISOR_PORT 0x5658
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
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) : \
55 static unsigned long vmware_tsc_khz __ro_after_init
;
57 static inline int __vmware_platform(void)
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
;
64 static unsigned long vmware_get_tsc_khz(void)
66 return vmware_tsc_khz
;
69 #ifdef CONFIG_PARAVIRT
70 static struct cyc2ns_data vmware_cyc2ns __ro_after_init
;
71 static int vmw_sched_clock __initdata
= 1;
73 static __init
int setup_vmw_sched_clock(char *s
)
78 early_param("no-vmw-sched-clock", setup_vmw_sched_clock
);
80 static unsigned long long vmware_sched_clock(void)
82 unsigned long long ns
;
84 ns
= mul_u64_u32_shr(rdtsc(), vmware_cyc2ns
.cyc2ns_mul
,
85 vmware_cyc2ns
.cyc2ns_shift
);
86 ns
-= vmware_cyc2ns
.cyc2ns_offset
;
90 static void __init
vmware_sched_clock_setup(void)
92 struct cyc2ns_data
*d
= &vmware_cyc2ns
;
93 unsigned long long tsc_now
= rdtsc();
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
,
100 pv_time_ops
.sched_clock
= vmware_sched_clock
;
101 pr_info("using sched offset of %llu ns\n", d
->cyc2ns_offset
);
104 static void __init
vmware_paravirt_ops_setup(void)
106 pv_info
.name
= "VMware hypervisor";
107 pv_cpu_ops
.io_delay
= paravirt_nop
;
109 if (vmware_tsc_khz
&& vmw_sched_clock
)
110 vmware_sched_clock_setup();
113 #define vmware_paravirt_ops_setup() do {} while (0)
116 static void __init
vmware_platform_setup(void)
118 uint32_t eax
, ebx
, ecx
, edx
;
119 uint64_t lpj
, tsc_khz
;
121 VMWARE_PORT(GETHZ
, eax
, ebx
, ecx
, edx
);
123 if (ebx
!= UINT_MAX
) {
124 lpj
= tsc_khz
= eax
| (((uint64_t)ebx
) << 32);
125 do_div(tsc_khz
, 1000);
126 WARN_ON(tsc_khz
>> 32);
127 pr_info("TSC freq read from hypervisor : %lu.%03lu MHz\n",
128 (unsigned long) tsc_khz
/ 1000,
129 (unsigned long) tsc_khz
% 1000);
136 vmware_tsc_khz
= tsc_khz
;
137 x86_platform
.calibrate_tsc
= vmware_get_tsc_khz
;
138 x86_platform
.calibrate_cpu
= vmware_get_tsc_khz
;
140 #ifdef CONFIG_X86_LOCAL_APIC
141 /* Skip lapic calibration since we know the bus frequency. */
142 lapic_timer_frequency
= ecx
/ HZ
;
143 pr_info("Host bus clock speed read from hypervisor : %u Hz\n",
147 pr_warn("Failed to get TSC freq from the hypervisor\n");
150 vmware_paravirt_ops_setup();
152 #ifdef CONFIG_X86_IO_APIC
158 * While checking the dmi string information, just checking the product
159 * serial key should be enough, as this will always have a VMware
160 * specific string when running under VMware hypervisor.
162 static uint32_t __init
vmware_platform(void)
164 if (boot_cpu_has(X86_FEATURE_HYPERVISOR
)) {
166 unsigned int hyper_vendor_id
[3];
168 cpuid(CPUID_VMWARE_INFO_LEAF
, &eax
, &hyper_vendor_id
[0],
169 &hyper_vendor_id
[1], &hyper_vendor_id
[2]);
170 if (!memcmp(hyper_vendor_id
, "VMwareVMware", 12))
171 return CPUID_VMWARE_INFO_LEAF
;
172 } else if (dmi_available
&& dmi_name_in_serial("VMware") &&
180 * VMware hypervisor takes care of exporting a reliable TSC to the guest.
181 * Still, due to timing difference when running on virtual cpus, the TSC can
182 * be marked as unstable in some cases. For example, the TSC sync check at
183 * bootup can fail due to a marginal offset between vcpus' TSCs (though the
184 * TSCs do not drift from each other). Also, the ACPI PM timer clocksource
185 * is not suitable as a watchdog when running on a hypervisor because the
186 * kernel may miss a wrap of the counter if the vcpu is descheduled for a
187 * long time. To skip these checks at runtime we set these capability bits,
188 * so that the kernel could just trust the hypervisor with providing a
189 * reliable virtual TSC that is suitable for timekeeping.
191 static void vmware_set_cpu_features(struct cpuinfo_x86
*c
)
193 set_cpu_cap(c
, X86_FEATURE_CONSTANT_TSC
);
194 set_cpu_cap(c
, X86_FEATURE_TSC_RELIABLE
);
197 /* Checks if hypervisor supports x2apic without VT-D interrupt remapping. */
198 static bool __init
vmware_legacy_x2apic_available(void)
200 uint32_t eax
, ebx
, ecx
, edx
;
201 VMWARE_PORT(GETVCPU_INFO
, eax
, ebx
, ecx
, edx
);
202 return (eax
& (1 << VMWARE_PORT_CMD_VCPU_RESERVED
)) == 0 &&
203 (eax
& (1 << VMWARE_PORT_CMD_LEGACY_X2APIC
)) != 0;
206 const __refconst
struct hypervisor_x86 x86_hyper_vmware
= {
208 .detect
= vmware_platform
,
209 .set_cpu_features
= vmware_set_cpu_features
,
210 .init_platform
= vmware_platform_setup
,
211 .x2apic_available
= vmware_legacy_x2apic_available
,
213 EXPORT_SYMBOL(x86_hyper_vmware
);