1 #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
2 #include <linux/bootmem.h>
5 #include <linux/kexec.h>
6 #include <linux/slab.h>
8 #include <xen/features.h>
10 #include <xen/interface/memory.h>
12 #include <asm/xen/hypercall.h>
13 #include <asm/xen/hypervisor.h>
15 #include <asm/e820/api.h>
21 EXPORT_SYMBOL_GPL(hypercall_page
);
24 * Pointer to the xen_vcpu_info structure or
25 * &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info
26 * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info
27 * but if the hypervisor supports VCPUOP_register_vcpu_info then it can point
28 * to xen_vcpu_info. The pointer is used in __xen_evtchn_do_upcall to
29 * acknowledge pending events.
30 * Also more subtly it is used by the patched version of irq enable/disable
31 * e.g. xen_irq_enable_direct and xen_iret in PV mode.
33 * The desire to be able to do those mask/unmask operations as a single
34 * instruction by using the per-cpu offset held in %gs is the real reason
35 * vcpu info is in a per-cpu pointer and the original reason for this
39 DEFINE_PER_CPU(struct vcpu_info
*, xen_vcpu
);
42 * Per CPU pages used if hypervisor supports VCPUOP_register_vcpu_info
43 * hypercall. This can be used both in PV and PVHVM mode. The structure
44 * overrides the default per_cpu(xen_vcpu, cpu) value.
46 DEFINE_PER_CPU(struct vcpu_info
, xen_vcpu_info
);
48 /* Linux <-> Xen vCPU id mapping */
49 DEFINE_PER_CPU(uint32_t, xen_vcpu_id
);
50 EXPORT_PER_CPU_SYMBOL(xen_vcpu_id
);
52 enum xen_domain_type xen_domain_type
= XEN_NATIVE
;
53 EXPORT_SYMBOL_GPL(xen_domain_type
);
55 unsigned long *machine_to_phys_mapping
= (void *)MACH2PHYS_VIRT_START
;
56 EXPORT_SYMBOL(machine_to_phys_mapping
);
57 unsigned long machine_to_phys_nr
;
58 EXPORT_SYMBOL(machine_to_phys_nr
);
60 struct start_info
*xen_start_info
;
61 EXPORT_SYMBOL_GPL(xen_start_info
);
63 struct shared_info xen_dummy_shared_info
;
65 __read_mostly
int xen_have_vector_callback
;
66 EXPORT_SYMBOL_GPL(xen_have_vector_callback
);
69 * NB: needs to live in .data because it's used by xen_prepare_pvh which runs
70 * before clearing the bss.
72 uint32_t xen_start_flags
__attribute__((section(".data"))) = 0;
73 EXPORT_SYMBOL(xen_start_flags
);
76 * Point at some empty memory to start with. We map the real shared_info
77 * page as soon as fixmap is up and running.
79 struct shared_info
*HYPERVISOR_shared_info
= &xen_dummy_shared_info
;
82 * Flag to determine whether vcpu info placement is available on all
83 * VCPUs. We assume it is to start with, and then set it to zero on
84 * the first failure. This is because it can succeed on some VCPUs
85 * and not others, since it can involve hypervisor memory allocation,
86 * or because the guest failed to guarantee all the appropriate
87 * constraints on all VCPUs (ie buffer can't cross a page boundary).
89 * Note that any particular CPU may be using a placed vcpu structure,
90 * but we can only optimise if the all are.
92 * 0: not available, 1: available
94 int xen_have_vcpu_info_placement
= 1;
96 static int xen_cpu_up_online(unsigned int cpu
)
98 xen_init_lock_cpu(cpu
);
102 int xen_cpuhp_setup(int (*cpu_up_prepare_cb
)(unsigned int),
103 int (*cpu_dead_cb
)(unsigned int))
107 rc
= cpuhp_setup_state_nocalls(CPUHP_XEN_PREPARE
,
108 "x86/xen/guest:prepare",
109 cpu_up_prepare_cb
, cpu_dead_cb
);
111 rc
= cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN
,
112 "x86/xen/guest:online",
113 xen_cpu_up_online
, NULL
);
115 cpuhp_remove_state_nocalls(CPUHP_XEN_PREPARE
);
118 return rc
>= 0 ? 0 : rc
;
121 static int xen_vcpu_setup_restore(int cpu
)
125 /* Any per_cpu(xen_vcpu) is stale, so reset it */
126 xen_vcpu_info_reset(cpu
);
129 * For PVH and PVHVM, setup online VCPUs only. The rest will
130 * be handled by hotplug.
132 if (xen_pv_domain() ||
133 (xen_hvm_domain() && cpu_online(cpu
))) {
134 rc
= xen_vcpu_setup(cpu
);
141 * On restore, set the vcpu placement up again.
142 * If it fails, then we're in a bad state, since
143 * we can't back out from using it...
145 void xen_vcpu_restore(void)
149 for_each_possible_cpu(cpu
) {
150 bool other_cpu
= (cpu
!= smp_processor_id());
153 if (xen_vcpu_nr(cpu
) == XEN_VCPU_ID_INVALID
)
156 /* Only Xen 4.5 and higher support this. */
157 is_up
= HYPERVISOR_vcpu_op(VCPUOP_is_up
,
158 xen_vcpu_nr(cpu
), NULL
) > 0;
160 if (other_cpu
&& is_up
&&
161 HYPERVISOR_vcpu_op(VCPUOP_down
, xen_vcpu_nr(cpu
), NULL
))
164 if (xen_pv_domain() || xen_feature(XENFEAT_hvm_safe_pvclock
))
165 xen_setup_runstate_info(cpu
);
167 rc
= xen_vcpu_setup_restore(cpu
);
169 pr_emerg_once("vcpu restore failed for cpu=%d err=%d. "
170 "System will hang.\n", cpu
, rc
);
172 * In case xen_vcpu_setup_restore() fails, do not bring up the
173 * VCPU. This helps us avoid the resulting OOPS when the VCPU
174 * accesses pvclock_vcpu_time via xen_vcpu (which is NULL.)
175 * Note that this does not improve the situation much -- now the
176 * VM hangs instead of OOPSing -- with the VCPUs that did not
177 * fail, spinning in stop_machine(), waiting for the failed
180 if (other_cpu
&& is_up
&& (rc
== 0) &&
181 HYPERVISOR_vcpu_op(VCPUOP_up
, xen_vcpu_nr(cpu
), NULL
))
186 void xen_vcpu_info_reset(int cpu
)
188 if (xen_vcpu_nr(cpu
) < MAX_VIRT_CPUS
) {
189 per_cpu(xen_vcpu
, cpu
) =
190 &HYPERVISOR_shared_info
->vcpu_info
[xen_vcpu_nr(cpu
)];
192 /* Set to NULL so that if somebody accesses it we get an OOPS */
193 per_cpu(xen_vcpu
, cpu
) = NULL
;
197 int xen_vcpu_setup(int cpu
)
199 struct vcpu_register_vcpu_info info
;
201 struct vcpu_info
*vcpup
;
203 BUG_ON(HYPERVISOR_shared_info
== &xen_dummy_shared_info
);
206 * This path is called on PVHVM at bootup (xen_hvm_smp_prepare_boot_cpu)
207 * and at restore (xen_vcpu_restore). Also called for hotplugged
208 * VCPUs (cpu_init -> xen_hvm_cpu_prepare_hvm).
209 * However, the hypercall can only be done once (see below) so if a VCPU
210 * is offlined and comes back online then let's not redo the hypercall.
212 * For PV it is called during restore (xen_vcpu_restore) and bootup
213 * (xen_setup_vcpu_info_placement). The hotplug mechanism does not
216 if (xen_hvm_domain()) {
217 if (per_cpu(xen_vcpu
, cpu
) == &per_cpu(xen_vcpu_info
, cpu
))
221 if (xen_have_vcpu_info_placement
) {
222 vcpup
= &per_cpu(xen_vcpu_info
, cpu
);
223 info
.mfn
= arbitrary_virt_to_mfn(vcpup
);
224 info
.offset
= offset_in_page(vcpup
);
227 * Check to see if the hypervisor will put the vcpu_info
228 * structure where we want it, which allows direct access via
230 * N.B. This hypercall can _only_ be called once per CPU.
231 * Subsequent calls will error out with -EINVAL. This is due to
232 * the fact that hypervisor has no unregister variant and this
233 * hypercall does not allow to over-write info.mfn and
236 err
= HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info
,
237 xen_vcpu_nr(cpu
), &info
);
240 pr_warn_once("register_vcpu_info failed: cpu=%d err=%d\n",
242 xen_have_vcpu_info_placement
= 0;
245 * This cpu is using the registered vcpu info, even if
246 * later ones fail to.
248 per_cpu(xen_vcpu
, cpu
) = vcpup
;
252 if (!xen_have_vcpu_info_placement
)
253 xen_vcpu_info_reset(cpu
);
255 return ((per_cpu(xen_vcpu
, cpu
) == NULL
) ? -ENODEV
: 0);
258 void xen_reboot(int reason
)
260 struct sched_shutdown r
= { .reason
= reason
};
263 for_each_online_cpu(cpu
)
266 if (HYPERVISOR_sched_op(SCHEDOP_shutdown
, &r
))
270 void xen_emergency_restart(void)
272 xen_reboot(SHUTDOWN_reboot
);
276 xen_panic_event(struct notifier_block
*this, unsigned long event
, void *ptr
)
278 if (!kexec_crash_loaded())
279 xen_reboot(SHUTDOWN_crash
);
283 static struct notifier_block xen_panic_block
= {
284 .notifier_call
= xen_panic_event
,
288 int xen_panic_handler_init(void)
290 atomic_notifier_chain_register(&panic_notifier_list
, &xen_panic_block
);
294 void xen_pin_vcpu(int cpu
)
296 static bool disable_pinning
;
297 struct sched_pin_override pin_override
;
303 pin_override
.pcpu
= cpu
;
304 ret
= HYPERVISOR_sched_op(SCHEDOP_pin_override
, &pin_override
);
306 /* Ignore errors when removing override. */
312 pr_warn("Unable to pin on physical cpu %d. In case of problems consider vcpu pinning.\n",
314 disable_pinning
= true;
317 WARN(1, "Trying to pin vcpu without having privilege to do so\n");
318 disable_pinning
= true;
322 pr_warn("Physical cpu %d not available for pinning. Check Xen cpu configuration.\n",
328 WARN(1, "rc %d while trying to pin vcpu\n", ret
);
329 disable_pinning
= true;
333 #ifdef CONFIG_HOTPLUG_CPU
334 void xen_arch_register_cpu(int num
)
336 arch_register_cpu(num
);
338 EXPORT_SYMBOL(xen_arch_register_cpu
);
340 void xen_arch_unregister_cpu(int num
)
342 arch_unregister_cpu(num
);
344 EXPORT_SYMBOL(xen_arch_unregister_cpu
);
347 #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
348 void __init
arch_xen_balloon_init(struct resource
*hostmem_resource
)
350 struct xen_memory_map memmap
;
352 unsigned int i
, last_guest_ram
;
353 phys_addr_t max_addr
= PFN_PHYS(max_pfn
);
354 struct e820_table
*xen_e820_table
;
355 const struct e820_entry
*entry
;
356 struct resource
*res
;
358 if (!xen_initial_domain())
361 xen_e820_table
= kmalloc(sizeof(*xen_e820_table
), GFP_KERNEL
);
365 memmap
.nr_entries
= ARRAY_SIZE(xen_e820_table
->entries
);
366 set_xen_guest_handle(memmap
.buffer
, xen_e820_table
->entries
);
367 rc
= HYPERVISOR_memory_op(XENMEM_machine_memory_map
, &memmap
);
369 pr_warn("%s: Can't read host e820 (%d)\n", __func__
, rc
);
374 for (i
= 0; i
< memmap
.nr_entries
; i
++) {
375 if (xen_e820_table
->entries
[i
].addr
>= max_addr
)
377 if (xen_e820_table
->entries
[i
].type
== E820_TYPE_RAM
)
381 entry
= &xen_e820_table
->entries
[last_guest_ram
];
382 if (max_addr
>= entry
->addr
+ entry
->size
)
383 goto out
; /* No unallocated host RAM. */
385 hostmem_resource
->start
= max_addr
;
386 hostmem_resource
->end
= entry
->addr
+ entry
->size
;
389 * Mark non-RAM regions between the end of dom0 RAM and end of host RAM
390 * as unavailable. The rest of that region can be used for hotplug-based
393 for (; i
< memmap
.nr_entries
; i
++) {
394 entry
= &xen_e820_table
->entries
[i
];
396 if (entry
->type
== E820_TYPE_RAM
)
399 if (entry
->addr
>= hostmem_resource
->end
)
402 res
= kzalloc(sizeof(*res
), GFP_KERNEL
);
406 res
->name
= "Unavailable host RAM";
407 res
->start
= entry
->addr
;
408 res
->end
= (entry
->addr
+ entry
->size
< hostmem_resource
->end
) ?
409 entry
->addr
+ entry
->size
: hostmem_resource
->end
;
410 rc
= insert_resource(hostmem_resource
, res
);
412 pr_warn("%s: Can't insert [%llx - %llx) (%d)\n",
413 __func__
, res
->start
, res
->end
, rc
);
420 kfree(xen_e820_table
);
422 #endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */