1 // SPDX-License-Identifier: GPL-2.0
4 * Architecture neutral utility routines for interacting with
5 * Hyper-V. This file is specifically for code that must be
6 * built-in to the kernel image when CONFIG_HYPERV is set
7 * (vs. being in a module) because it is called from architecture
8 * specific code under arch/.
10 * Copyright (C) 2021, Microsoft, Inc.
12 * Author : Michael Kelley <mikelley@microsoft.com>
15 #include <linux/types.h>
16 #include <linux/export.h>
17 #include <linux/bitfield.h>
18 #include <linux/cpumask.h>
19 #include <linux/ptrace.h>
20 #include <linux/slab.h>
21 #include <asm/hyperv-tlfs.h>
22 #include <asm/mshyperv.h>
25 * hv_root_partition and ms_hyperv are defined here with other Hyper-V
26 * specific globals so they are shared across all architectures and are
27 * built only when CONFIG_HYPERV is defined. But on x86,
28 * ms_hyperv_init_platform() is built even when CONFIG_HYPERV is not
29 * defined, and it uses these two variables. So mark them as __weak
30 * here, allowing for an overriding definition in the module containing
31 * ms_hyperv_init_platform().
33 bool __weak hv_root_partition;
34 EXPORT_SYMBOL_GPL(hv_root_partition);
36 struct ms_hyperv_info __weak ms_hyperv;
37 EXPORT_SYMBOL_GPL(ms_hyperv);
40 EXPORT_SYMBOL_GPL(hv_vp_index);
43 EXPORT_SYMBOL_GPL(hv_max_vp_index);
45 void __percpu **hyperv_pcpu_input_arg;
46 EXPORT_SYMBOL_GPL(hyperv_pcpu_input_arg);
48 void __percpu **hyperv_pcpu_output_arg;
49 EXPORT_SYMBOL_GPL(hyperv_pcpu_output_arg);
52 * Hyper-V specific initialization and shutdown code that is
53 * common across all architectures. Called from architecture
54 * specific initialization functions.
57 void __init hv_common_free(void)
62 free_percpu(hyperv_pcpu_output_arg);
63 hyperv_pcpu_output_arg = NULL;
65 free_percpu(hyperv_pcpu_input_arg);
66 hyperv_pcpu_input_arg = NULL;
69 int __init hv_common_init(void)
74 * Allocate the per-CPU state for the hypercall input arg.
75 * If this allocation fails, we will not be able to setup
76 * (per-CPU) hypercall input page and thus this failure is
79 hyperv_pcpu_input_arg = alloc_percpu(void *);
80 BUG_ON(!hyperv_pcpu_input_arg);
82 /* Allocate the per-CPU state for output arg for root */
83 if (hv_root_partition) {
84 hyperv_pcpu_output_arg = alloc_percpu(void *);
85 BUG_ON(!hyperv_pcpu_output_arg);
88 hv_vp_index = kmalloc_array(num_possible_cpus(), sizeof(*hv_vp_index),
95 for (i = 0; i < num_possible_cpus(); i++)
96 hv_vp_index[i] = VP_INVAL;
102 * Hyper-V specific initialization and die code for
103 * individual CPUs that is common across all architectures.
104 * Called by the CPU hotplug mechanism.
107 int hv_common_cpu_init(unsigned int cpu)
109 void **inputarg, **outputarg;
112 int pgcount = hv_root_partition ? 2 : 1;
114 /* hv_cpu_init() can be called with IRQs disabled from hv_resume() */
115 flags = irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL;
117 inputarg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
118 *inputarg = kmalloc(pgcount * HV_HYP_PAGE_SIZE, flags);
122 if (hv_root_partition) {
123 outputarg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
124 *outputarg = (char *)(*inputarg) + HV_HYP_PAGE_SIZE;
127 msr_vp_index = hv_get_register(HV_REGISTER_VP_INDEX);
129 hv_vp_index[cpu] = msr_vp_index;
131 if (msr_vp_index > hv_max_vp_index)
132 hv_max_vp_index = msr_vp_index;
137 int hv_common_cpu_die(unsigned int cpu)
140 void **inputarg, **outputarg;
143 local_irq_save(flags);
145 inputarg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
149 if (hv_root_partition) {
150 outputarg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
154 local_irq_restore(flags);
161 /* Bit mask of the extended capability to query: see HV_EXT_CAPABILITY_xxx */
162 bool hv_query_ext_cap(u64 cap_query)
165 * The address of the 'hv_extended_cap' variable will be used as an
166 * output parameter to the hypercall below and so it should be
167 * compatible with 'virt_to_phys'. Which means, it's address should be
168 * directly mapped. Use 'static' to keep it compatible; stack variables
169 * can be virtually mapped, making them incompatible with
171 * Hypercall input/output addresses should also be 8-byte aligned.
173 static u64 hv_extended_cap __aligned(8);
174 static bool hv_extended_cap_queried;
178 * Querying extended capabilities is an extended hypercall. Check if the
179 * partition supports extended hypercall, first.
181 if (!(ms_hyperv.priv_high & HV_ENABLE_EXTENDED_HYPERCALLS))
184 /* Extended capabilities do not change at runtime. */
185 if (hv_extended_cap_queried)
186 return hv_extended_cap & cap_query;
188 status = hv_do_hypercall(HV_EXT_CALL_QUERY_CAPABILITIES, NULL,
192 * The query extended capabilities hypercall should not fail under
193 * any normal circumstances. Avoid repeatedly making the hypercall, on
196 hv_extended_cap_queried = true;
197 if (!hv_result_success(status)) {
198 pr_err("Hyper-V: Extended query capabilities hypercall failed 0x%llx\n",
203 return hv_extended_cap & cap_query;
205 EXPORT_SYMBOL_GPL(hv_query_ext_cap);
207 /* These __weak functions provide default "no-op" behavior and
208 * may be overridden by architecture specific versions. Architectures
209 * for which the default "no-op" behavior is sufficient can leave
210 * them unimplemented and not be cluttered with a bunch of stub
211 * functions in arch-specific code.
214 bool __weak hv_is_isolation_supported(void)
218 EXPORT_SYMBOL_GPL(hv_is_isolation_supported);
220 void __weak hv_setup_vmbus_handler(void (*handler)(void))
223 EXPORT_SYMBOL_GPL(hv_setup_vmbus_handler);
225 void __weak hv_remove_vmbus_handler(void)
228 EXPORT_SYMBOL_GPL(hv_remove_vmbus_handler);
230 void __weak hv_setup_kexec_handler(void (*handler)(void))
233 EXPORT_SYMBOL_GPL(hv_setup_kexec_handler);
235 void __weak hv_remove_kexec_handler(void)
238 EXPORT_SYMBOL_GPL(hv_remove_kexec_handler);
240 void __weak hv_setup_crash_handler(void (*handler)(struct pt_regs *regs))
243 EXPORT_SYMBOL_GPL(hv_setup_crash_handler);
245 void __weak hv_remove_crash_handler(void)
248 EXPORT_SYMBOL_GPL(hv_remove_crash_handler);
250 void __weak hyperv_cleanup(void)
253 EXPORT_SYMBOL_GPL(hyperv_cleanup);