Merge tag 'char-misc-4.15-rc1' of ssh://gitolite.kernel.org/pub/scm/linux/kernel...
[sfrench/cifs-2.6.git] / arch / x86 / hyperv / hv_init.c
1 /*
2  * X86 specific Hyper-V initialization code.
3  *
4  * Copyright (C) 2016, Microsoft, Inc.
5  *
6  * Author : K. Y. Srinivasan <kys@microsoft.com>
7  *
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.
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  */
19
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>
26 #include <linux/mm.h>
27 #include <linux/clockchips.h>
28 #include <linux/hyperv.h>
29 #include <linux/slab.h>
30 #include <linux/cpuhotplug.h>
31
32 #ifdef CONFIG_HYPERV_TSCPAGE
33
34 static struct ms_hyperv_tsc_page *tsc_pg;
35
36 struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
37 {
38         return tsc_pg;
39 }
40
41 static u64 read_hv_clock_tsc(struct clocksource *arg)
42 {
43         u64 current_tick = hv_read_tsc_page(tsc_pg);
44
45         if (current_tick == U64_MAX)
46                 rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
47
48         return current_tick;
49 }
50
51 static struct clocksource hyperv_cs_tsc = {
52                 .name           = "hyperv_clocksource_tsc_page",
53                 .rating         = 400,
54                 .read           = read_hv_clock_tsc,
55                 .mask           = CLOCKSOURCE_MASK(64),
56                 .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
57 };
58 #endif
59
60 static u64 read_hv_clock_msr(struct clocksource *arg)
61 {
62         u64 current_tick;
63         /*
64          * Read the partition counter to get the current tick count. This count
65          * is set to 0 when the partition is created and is incremented in
66          * 100 nanosecond units.
67          */
68         rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
69         return current_tick;
70 }
71
72 static struct clocksource hyperv_cs_msr = {
73         .name           = "hyperv_clocksource_msr",
74         .rating         = 400,
75         .read           = read_hv_clock_msr,
76         .mask           = CLOCKSOURCE_MASK(64),
77         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
78 };
79
80 void *hv_hypercall_pg;
81 EXPORT_SYMBOL_GPL(hv_hypercall_pg);
82 struct clocksource *hyperv_cs;
83 EXPORT_SYMBOL_GPL(hyperv_cs);
84
85 u32 *hv_vp_index;
86 EXPORT_SYMBOL_GPL(hv_vp_index);
87
88 u32 hv_max_vp_index;
89
90 static int hv_cpu_init(unsigned int cpu)
91 {
92         u64 msr_vp_index;
93
94         hv_get_vp_index(msr_vp_index);
95
96         hv_vp_index[smp_processor_id()] = msr_vp_index;
97
98         if (msr_vp_index > hv_max_vp_index)
99                 hv_max_vp_index = msr_vp_index;
100
101         return 0;
102 }
103
104 /*
105  * This function is to be invoked early in the boot sequence after the
106  * hypervisor has been detected.
107  *
108  * 1. Setup the hypercall page.
109  * 2. Register Hyper-V specific clocksource.
110  */
111 void hyperv_init(void)
112 {
113         u64 guest_id;
114         union hv_x64_msr_hypercall_contents hypercall_msr;
115
116         if (x86_hyper_type != X86_HYPER_MS_HYPERV)
117                 return;
118
119         /* Allocate percpu VP index */
120         hv_vp_index = kmalloc_array(num_possible_cpus(), sizeof(*hv_vp_index),
121                                     GFP_KERNEL);
122         if (!hv_vp_index)
123                 return;
124
125         if (cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online",
126                               hv_cpu_init, NULL) < 0)
127                 goto free_vp_index;
128
129         /*
130          * Setup the hypercall page and enable hypercalls.
131          * 1. Register the guest ID
132          * 2. Enable the hypercall and register the hypercall page
133          */
134         guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0);
135         wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
136
137         hv_hypercall_pg  = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_RX);
138         if (hv_hypercall_pg == NULL) {
139                 wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
140                 goto free_vp_index;
141         }
142
143         rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
144         hypercall_msr.enable = 1;
145         hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg);
146         wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
147
148         hyper_alloc_mmu();
149
150         /*
151          * Register Hyper-V specific clocksource.
152          */
153 #ifdef CONFIG_HYPERV_TSCPAGE
154         if (ms_hyperv.features & HV_X64_MSR_REFERENCE_TSC_AVAILABLE) {
155                 union hv_x64_msr_hypercall_contents tsc_msr;
156
157                 tsc_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
158                 if (!tsc_pg)
159                         goto register_msr_cs;
160
161                 hyperv_cs = &hyperv_cs_tsc;
162
163                 rdmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
164
165                 tsc_msr.enable = 1;
166                 tsc_msr.guest_physical_address = vmalloc_to_pfn(tsc_pg);
167
168                 wrmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
169
170                 hyperv_cs_tsc.archdata.vclock_mode = VCLOCK_HVCLOCK;
171
172                 clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);
173                 return;
174         }
175 register_msr_cs:
176 #endif
177         /*
178          * For 32 bit guests just use the MSR based mechanism for reading
179          * the partition counter.
180          */
181
182         hyperv_cs = &hyperv_cs_msr;
183         if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
184                 clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);
185
186         return;
187
188 free_vp_index:
189         kfree(hv_vp_index);
190         hv_vp_index = NULL;
191 }
192
193 /*
194  * This routine is called before kexec/kdump, it does the required cleanup.
195  */
196 void hyperv_cleanup(void)
197 {
198         union hv_x64_msr_hypercall_contents hypercall_msr;
199
200         /* Reset our OS id */
201         wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
202
203         /* Reset the hypercall page */
204         hypercall_msr.as_uint64 = 0;
205         wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
206
207         /* Reset the TSC page */
208         hypercall_msr.as_uint64 = 0;
209         wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64);
210 }
211 EXPORT_SYMBOL_GPL(hyperv_cleanup);
212
213 void hyperv_report_panic(struct pt_regs *regs, long err)
214 {
215         static bool panic_reported;
216         u64 guest_id;
217
218         /*
219          * We prefer to report panic on 'die' chain as we have proper
220          * registers to report, but if we miss it (e.g. on BUG()) we need
221          * to report it on 'panic'.
222          */
223         if (panic_reported)
224                 return;
225         panic_reported = true;
226
227         rdmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
228
229         wrmsrl(HV_X64_MSR_CRASH_P0, err);
230         wrmsrl(HV_X64_MSR_CRASH_P1, guest_id);
231         wrmsrl(HV_X64_MSR_CRASH_P2, regs->ip);
232         wrmsrl(HV_X64_MSR_CRASH_P3, regs->ax);
233         wrmsrl(HV_X64_MSR_CRASH_P4, regs->sp);
234
235         /*
236          * Let Hyper-V know there is crash data available
237          */
238         wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
239 }
240 EXPORT_SYMBOL_GPL(hyperv_report_panic);
241
242 bool hv_is_hypercall_page_setup(void)
243 {
244         union hv_x64_msr_hypercall_contents hypercall_msr;
245
246         /* Check if the hypercall page is setup */
247         hypercall_msr.as_uint64 = 0;
248         rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
249
250         if (!hypercall_msr.enable)
251                 return false;
252
253         return true;
254 }
255 EXPORT_SYMBOL_GPL(hv_is_hypercall_page_setup);