2 #include <linux/kexec.h>
4 #include <xen/features.h>
7 #include <asm/xen/hypercall.h>
8 #include <asm/xen/hypervisor.h>
10 #include <asm/e820/api.h>
16 EXPORT_SYMBOL_GPL(hypercall_page
);
19 * Pointer to the xen_vcpu_info structure or
20 * &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info
21 * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info
22 * but if the hypervisor supports VCPUOP_register_vcpu_info then it can point
23 * to xen_vcpu_info. The pointer is used in __xen_evtchn_do_upcall to
24 * acknowledge pending events.
25 * Also more subtly it is used by the patched version of irq enable/disable
26 * e.g. xen_irq_enable_direct and xen_iret in PV mode.
28 * The desire to be able to do those mask/unmask operations as a single
29 * instruction by using the per-cpu offset held in %gs is the real reason
30 * vcpu info is in a per-cpu pointer and the original reason for this
34 DEFINE_PER_CPU(struct vcpu_info
*, xen_vcpu
);
37 * Per CPU pages used if hypervisor supports VCPUOP_register_vcpu_info
38 * hypercall. This can be used both in PV and PVHVM mode. The structure
39 * overrides the default per_cpu(xen_vcpu, cpu) value.
41 DEFINE_PER_CPU(struct vcpu_info
, xen_vcpu_info
);
43 /* Linux <-> Xen vCPU id mapping */
44 DEFINE_PER_CPU(uint32_t, xen_vcpu_id
);
45 EXPORT_PER_CPU_SYMBOL(xen_vcpu_id
);
47 enum xen_domain_type xen_domain_type
= XEN_NATIVE
;
48 EXPORT_SYMBOL_GPL(xen_domain_type
);
50 unsigned long *machine_to_phys_mapping
= (void *)MACH2PHYS_VIRT_START
;
51 EXPORT_SYMBOL(machine_to_phys_mapping
);
52 unsigned long machine_to_phys_nr
;
53 EXPORT_SYMBOL(machine_to_phys_nr
);
55 struct start_info
*xen_start_info
;
56 EXPORT_SYMBOL_GPL(xen_start_info
);
58 struct shared_info xen_dummy_shared_info
;
60 __read_mostly
int xen_have_vector_callback
;
61 EXPORT_SYMBOL_GPL(xen_have_vector_callback
);
64 * Point at some empty memory to start with. We map the real shared_info
65 * page as soon as fixmap is up and running.
67 struct shared_info
*HYPERVISOR_shared_info
= &xen_dummy_shared_info
;
70 * Flag to determine whether vcpu info placement is available on all
71 * VCPUs. We assume it is to start with, and then set it to zero on
72 * the first failure. This is because it can succeed on some VCPUs
73 * and not others, since it can involve hypervisor memory allocation,
74 * or because the guest failed to guarantee all the appropriate
75 * constraints on all VCPUs (ie buffer can't cross a page boundary).
77 * Note that any particular CPU may be using a placed vcpu structure,
78 * but we can only optimise if the all are.
80 * 0: not available, 1: available
82 int xen_have_vcpu_info_placement
= 1;
84 static int xen_cpu_up_online(unsigned int cpu
)
86 xen_init_lock_cpu(cpu
);
90 int xen_cpuhp_setup(int (*cpu_up_prepare_cb
)(unsigned int),
91 int (*cpu_dead_cb
)(unsigned int))
95 rc
= cpuhp_setup_state_nocalls(CPUHP_XEN_PREPARE
,
96 "x86/xen/hvm_guest:prepare",
97 cpu_up_prepare_cb
, cpu_dead_cb
);
99 rc
= cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN
,
100 "x86/xen/hvm_guest:online",
101 xen_cpu_up_online
, NULL
);
103 cpuhp_remove_state_nocalls(CPUHP_XEN_PREPARE
);
106 return rc
>= 0 ? 0 : rc
;
109 static int xen_vcpu_setup_restore(int cpu
)
113 /* Any per_cpu(xen_vcpu) is stale, so reset it */
114 xen_vcpu_info_reset(cpu
);
117 * For PVH and PVHVM, setup online VCPUs only. The rest will
118 * be handled by hotplug.
120 if (xen_pv_domain() ||
121 (xen_hvm_domain() && cpu_online(cpu
))) {
122 rc
= xen_vcpu_setup(cpu
);
129 * On restore, set the vcpu placement up again.
130 * If it fails, then we're in a bad state, since
131 * we can't back out from using it...
133 void xen_vcpu_restore(void)
137 for_each_possible_cpu(cpu
) {
138 bool other_cpu
= (cpu
!= smp_processor_id());
141 if (xen_vcpu_nr(cpu
) == XEN_VCPU_ID_INVALID
)
144 /* Only Xen 4.5 and higher support this. */
145 is_up
= HYPERVISOR_vcpu_op(VCPUOP_is_up
,
146 xen_vcpu_nr(cpu
), NULL
) > 0;
148 if (other_cpu
&& is_up
&&
149 HYPERVISOR_vcpu_op(VCPUOP_down
, xen_vcpu_nr(cpu
), NULL
))
152 if (xen_pv_domain() || xen_feature(XENFEAT_hvm_safe_pvclock
))
153 xen_setup_runstate_info(cpu
);
155 rc
= xen_vcpu_setup_restore(cpu
);
157 pr_emerg_once("vcpu restore failed for cpu=%d err=%d. "
158 "System will hang.\n", cpu
, rc
);
160 * In case xen_vcpu_setup_restore() fails, do not bring up the
161 * VCPU. This helps us avoid the resulting OOPS when the VCPU
162 * accesses pvclock_vcpu_time via xen_vcpu (which is NULL.)
163 * Note that this does not improve the situation much -- now the
164 * VM hangs instead of OOPSing -- with the VCPUs that did not
165 * fail, spinning in stop_machine(), waiting for the failed
168 if (other_cpu
&& is_up
&& (rc
== 0) &&
169 HYPERVISOR_vcpu_op(VCPUOP_up
, xen_vcpu_nr(cpu
), NULL
))
174 void xen_vcpu_info_reset(int cpu
)
176 if (xen_vcpu_nr(cpu
) < MAX_VIRT_CPUS
) {
177 per_cpu(xen_vcpu
, cpu
) =
178 &HYPERVISOR_shared_info
->vcpu_info
[xen_vcpu_nr(cpu
)];
180 /* Set to NULL so that if somebody accesses it we get an OOPS */
181 per_cpu(xen_vcpu
, cpu
) = NULL
;
185 int xen_vcpu_setup(int cpu
)
187 struct vcpu_register_vcpu_info info
;
189 struct vcpu_info
*vcpup
;
191 BUG_ON(HYPERVISOR_shared_info
== &xen_dummy_shared_info
);
194 * This path is called on PVHVM at bootup (xen_hvm_smp_prepare_boot_cpu)
195 * and at restore (xen_vcpu_restore). Also called for hotplugged
196 * VCPUs (cpu_init -> xen_hvm_cpu_prepare_hvm).
197 * However, the hypercall can only be done once (see below) so if a VCPU
198 * is offlined and comes back online then let's not redo the hypercall.
200 * For PV it is called during restore (xen_vcpu_restore) and bootup
201 * (xen_setup_vcpu_info_placement). The hotplug mechanism does not
204 if (xen_hvm_domain()) {
205 if (per_cpu(xen_vcpu
, cpu
) == &per_cpu(xen_vcpu_info
, cpu
))
209 if (xen_have_vcpu_info_placement
) {
210 vcpup
= &per_cpu(xen_vcpu_info
, cpu
);
211 info
.mfn
= arbitrary_virt_to_mfn(vcpup
);
212 info
.offset
= offset_in_page(vcpup
);
215 * Check to see if the hypervisor will put the vcpu_info
216 * structure where we want it, which allows direct access via
218 * N.B. This hypercall can _only_ be called once per CPU.
219 * Subsequent calls will error out with -EINVAL. This is due to
220 * the fact that hypervisor has no unregister variant and this
221 * hypercall does not allow to over-write info.mfn and
224 err
= HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info
,
225 xen_vcpu_nr(cpu
), &info
);
228 pr_warn_once("register_vcpu_info failed: cpu=%d err=%d\n",
230 xen_have_vcpu_info_placement
= 0;
233 * This cpu is using the registered vcpu info, even if
234 * later ones fail to.
236 per_cpu(xen_vcpu
, cpu
) = vcpup
;
240 if (!xen_have_vcpu_info_placement
)
241 xen_vcpu_info_reset(cpu
);
243 return ((per_cpu(xen_vcpu
, cpu
) == NULL
) ? -ENODEV
: 0);
246 void xen_reboot(int reason
)
248 struct sched_shutdown r
= { .reason
= reason
};
251 for_each_online_cpu(cpu
)
254 if (HYPERVISOR_sched_op(SCHEDOP_shutdown
, &r
))
258 void xen_emergency_restart(void)
260 xen_reboot(SHUTDOWN_reboot
);
264 xen_panic_event(struct notifier_block
*this, unsigned long event
, void *ptr
)
266 if (!kexec_crash_loaded())
267 xen_reboot(SHUTDOWN_crash
);
271 static struct notifier_block xen_panic_block
= {
272 .notifier_call
= xen_panic_event
,
276 int xen_panic_handler_init(void)
278 atomic_notifier_chain_register(&panic_notifier_list
, &xen_panic_block
);
282 void xen_pin_vcpu(int cpu
)
284 static bool disable_pinning
;
285 struct sched_pin_override pin_override
;
291 pin_override
.pcpu
= cpu
;
292 ret
= HYPERVISOR_sched_op(SCHEDOP_pin_override
, &pin_override
);
294 /* Ignore errors when removing override. */
300 pr_warn("Unable to pin on physical cpu %d. In case of problems consider vcpu pinning.\n",
302 disable_pinning
= true;
305 WARN(1, "Trying to pin vcpu without having privilege to do so\n");
306 disable_pinning
= true;
310 pr_warn("Physical cpu %d not available for pinning. Check Xen cpu configuration.\n",
316 WARN(1, "rc %d while trying to pin vcpu\n", ret
);
317 disable_pinning
= true;
321 #ifdef CONFIG_HOTPLUG_CPU
322 void xen_arch_register_cpu(int num
)
324 arch_register_cpu(num
);
326 EXPORT_SYMBOL(xen_arch_register_cpu
);
328 void xen_arch_unregister_cpu(int num
)
330 arch_unregister_cpu(num
);
332 EXPORT_SYMBOL(xen_arch_unregister_cpu
);