2 * X86 specific Hyper-V initialization code.
4 * Copyright (C) 2016, Microsoft, Inc.
6 * Author : K. Y. Srinivasan <kys@microsoft.com>
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 as published
10 * by the Free Software Foundation.
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
20 #include <linux/types.h>
21 #include <asm/hypervisor.h>
22 #include <asm/hyperv.h>
23 #include <asm/mshyperv.h>
24 #include <linux/version.h>
25 #include <linux/vmalloc.h>
27 #include <linux/clockchips.h>
32 static struct ms_hyperv_tsc_page
*tsc_pg
;
34 static u64
read_hv_clock_tsc(struct clocksource
*arg
)
38 if (tsc_pg
->tsc_sequence
!= 0) {
40 * Use the tsc page to compute the value.
45 u32 sequence
= tsc_pg
->tsc_sequence
;
47 u64 scale
= tsc_pg
->tsc_scale
;
48 s64 offset
= tsc_pg
->tsc_offset
;
51 /* current_tick = ((cur_tsc *scale) >> 64) + offset */
53 : "=d" (current_tick
), "=a" (tmp
)
54 : "a" (cur_tsc
), "r" (scale
));
56 current_tick
+= offset
;
57 if (tsc_pg
->tsc_sequence
== sequence
)
60 if (tsc_pg
->tsc_sequence
!= 0)
63 * Fallback using MSR method.
68 rdmsrl(HV_X64_MSR_TIME_REF_COUNT
, current_tick
);
72 static struct clocksource hyperv_cs_tsc
= {
73 .name
= "hyperv_clocksource_tsc_page",
75 .read
= read_hv_clock_tsc
,
76 .mask
= CLOCKSOURCE_MASK(64),
77 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
81 static u64
read_hv_clock_msr(struct clocksource
*arg
)
85 * Read the partition counter to get the current tick count. This count
86 * is set to 0 when the partition is created and is incremented in
87 * 100 nanosecond units.
89 rdmsrl(HV_X64_MSR_TIME_REF_COUNT
, current_tick
);
93 static struct clocksource hyperv_cs_msr
= {
94 .name
= "hyperv_clocksource_msr",
96 .read
= read_hv_clock_msr
,
97 .mask
= CLOCKSOURCE_MASK(64),
98 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
101 static void *hypercall_pg
;
103 * This function is to be invoked early in the boot sequence after the
104 * hypervisor has been detected.
106 * 1. Setup the hypercall page.
107 * 2. Register Hyper-V specific clocksource.
109 void hyperv_init(void)
112 union hv_x64_msr_hypercall_contents hypercall_msr
;
114 if (x86_hyper
!= &x86_hyper_ms_hyperv
)
118 * Setup the hypercall page and enable hypercalls.
119 * 1. Register the guest ID
120 * 2. Enable the hypercall and register the hypercall page
122 guest_id
= generate_guest_id(0, LINUX_VERSION_CODE
, 0);
123 wrmsrl(HV_X64_MSR_GUEST_OS_ID
, guest_id
);
125 hypercall_pg
= __vmalloc(PAGE_SIZE
, GFP_KERNEL
, PAGE_KERNEL_EXEC
);
126 if (hypercall_pg
== NULL
) {
127 wrmsrl(HV_X64_MSR_GUEST_OS_ID
, 0);
131 rdmsrl(HV_X64_MSR_HYPERCALL
, hypercall_msr
.as_uint64
);
132 hypercall_msr
.enable
= 1;
133 hypercall_msr
.guest_physical_address
= vmalloc_to_pfn(hypercall_pg
);
134 wrmsrl(HV_X64_MSR_HYPERCALL
, hypercall_msr
.as_uint64
);
137 * Register Hyper-V specific clocksource.
140 if (ms_hyperv
.features
& HV_X64_MSR_REFERENCE_TSC_AVAILABLE
) {
141 union hv_x64_msr_hypercall_contents tsc_msr
;
143 tsc_pg
= __vmalloc(PAGE_SIZE
, GFP_KERNEL
, PAGE_KERNEL
);
145 clocksource_register_hz(&hyperv_cs_msr
, NSEC_PER_SEC
/100);
149 rdmsrl(HV_X64_MSR_REFERENCE_TSC
, tsc_msr
.as_uint64
);
152 tsc_msr
.guest_physical_address
= vmalloc_to_pfn(tsc_pg
);
154 wrmsrl(HV_X64_MSR_REFERENCE_TSC
, tsc_msr
.as_uint64
);
155 clocksource_register_hz(&hyperv_cs_tsc
, NSEC_PER_SEC
/100);
160 * For 32 bit guests just use the MSR based mechanism for reading
161 * the partition counter.
164 if (ms_hyperv
.features
& HV_X64_MSR_TIME_REF_COUNT_AVAILABLE
)
165 clocksource_register_hz(&hyperv_cs_msr
, NSEC_PER_SEC
/100);
169 * This routine is called before kexec/kdump, it does the required cleanup.
171 void hyperv_cleanup(void)
173 union hv_x64_msr_hypercall_contents hypercall_msr
;
175 /* Reset our OS id */
176 wrmsrl(HV_X64_MSR_GUEST_OS_ID
, 0);
178 /* Reset the hypercall page */
179 hypercall_msr
.as_uint64
= 0;
180 wrmsrl(HV_X64_MSR_HYPERCALL
, hypercall_msr
.as_uint64
);
182 /* Reset the TSC page */
183 hypercall_msr
.as_uint64
= 0;
184 wrmsrl(HV_X64_MSR_REFERENCE_TSC
, hypercall_msr
.as_uint64
);
186 EXPORT_SYMBOL_GPL(hyperv_cleanup
);
189 * hv_do_hypercall- Invoke the specified hypercall
191 u64
hv_do_hypercall(u64 control
, void *input
, void *output
)
193 u64 input_address
= (input
) ? virt_to_phys(input
) : 0;
194 u64 output_address
= (output
) ? virt_to_phys(output
) : 0;
199 return (u64
)ULLONG_MAX
;
201 __asm__
__volatile__("mov %0, %%r8" : : "r" (output_address
) : "r8");
202 __asm__
__volatile__("call *%3" : "=a" (hv_status
) :
203 "c" (control
), "d" (input_address
),
210 u32 control_hi
= control
>> 32;
211 u32 control_lo
= control
& 0xFFFFFFFF;
212 u32 hv_status_hi
= 1;
213 u32 hv_status_lo
= 1;
214 u32 input_address_hi
= input_address
>> 32;
215 u32 input_address_lo
= input_address
& 0xFFFFFFFF;
216 u32 output_address_hi
= output_address
>> 32;
217 u32 output_address_lo
= output_address
& 0xFFFFFFFF;
220 return (u64
)ULLONG_MAX
;
222 __asm__
__volatile__ ("call *%8" : "=d"(hv_status_hi
),
223 "=a"(hv_status_lo
) : "d" (control_hi
),
224 "a" (control_lo
), "b" (input_address_hi
),
225 "c" (input_address_lo
), "D"(output_address_hi
),
226 "S"(output_address_lo
), "m" (hypercall_pg
));
228 return hv_status_lo
| ((u64
)hv_status_hi
<< 32);
231 EXPORT_SYMBOL_GPL(hv_do_hypercall
);
233 void hyperv_report_panic(struct pt_regs
*regs
)
235 static bool panic_reported
;
238 * We prefer to report panic on 'die' chain as we have proper
239 * registers to report, but if we miss it (e.g. on BUG()) we need
240 * to report it on 'panic'.
244 panic_reported
= true;
246 wrmsrl(HV_X64_MSR_CRASH_P0
, regs
->ip
);
247 wrmsrl(HV_X64_MSR_CRASH_P1
, regs
->ax
);
248 wrmsrl(HV_X64_MSR_CRASH_P2
, regs
->bx
);
249 wrmsrl(HV_X64_MSR_CRASH_P3
, regs
->cx
);
250 wrmsrl(HV_X64_MSR_CRASH_P4
, regs
->dx
);
253 * Let Hyper-V know there is crash data available
255 wrmsrl(HV_X64_MSR_CRASH_CTL
, HV_CRASH_CTL_CRASH_NOTIFY
);
257 EXPORT_SYMBOL_GPL(hyperv_report_panic
);
259 bool hv_is_hypercall_page_setup(void)
261 union hv_x64_msr_hypercall_contents hypercall_msr
;
263 /* Check if the hypercall page is setup */
264 hypercall_msr
.as_uint64
= 0;
265 rdmsrl(HV_X64_MSR_HYPERCALL
, hypercall_msr
.as_uint64
);
267 if (!hypercall_msr
.enable
)
272 EXPORT_SYMBOL_GPL(hv_is_hypercall_page_setup
);