xref: /openbmc/qemu/hw/acpi/cpu_hotplug.c (revision c16de0d9)
1 /*
2  * QEMU ACPI hotplug utilities
3  *
4  * Copyright (C) 2013 Red Hat Inc
5  *
6  * Authors:
7  *   Igor Mammedov <imammedo@redhat.com>
8  *
9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
10  * See the COPYING file in the top-level directory.
11  */
12 #include "qemu/osdep.h"
13 #include "hw/acpi/cpu_hotplug.h"
14 #include "qapi/error.h"
15 #include "hw/core/cpu.h"
16 #include "hw/i386/pc.h"
17 #include "hw/pci/pci.h"
18 #include "qemu/error-report.h"
19 
20 #define CPU_EJECT_METHOD "CPEJ"
21 #define CPU_MAT_METHOD "CPMA"
22 #define CPU_ON_BITMAP "CPON"
23 #define CPU_STATUS_METHOD "CPST"
24 #define CPU_STATUS_MAP "PRS"
25 #define CPU_SCAN_METHOD "PRSC"
26 
27 static uint64_t cpu_status_read(void *opaque, hwaddr addr, unsigned int size)
28 {
29     AcpiCpuHotplug *cpus = opaque;
30     uint64_t val = cpus->sts[addr];
31 
32     return val;
33 }
34 
35 static void cpu_status_write(void *opaque, hwaddr addr, uint64_t data,
36                              unsigned int size)
37 {
38     /* firmware never used to write in CPU present bitmap so use
39        this fact as means to switch QEMU into modern CPU hotplug
40        mode by writing 0 at the beginning of legacy CPU bitmap
41      */
42     if (addr == 0 && data == 0) {
43         AcpiCpuHotplug *cpus = opaque;
44         object_property_set_bool(cpus->device, "cpu-hotplug-legacy", false,
45                                  &error_abort);
46     }
47 }
48 
49 static const MemoryRegionOps AcpiCpuHotplug_ops = {
50     .read = cpu_status_read,
51     .write = cpu_status_write,
52     .endianness = DEVICE_LITTLE_ENDIAN,
53     .valid = {
54         .min_access_size = 1,
55         .max_access_size = 4,
56     },
57     .impl = {
58         .max_access_size = 1,
59     },
60 };
61 
62 static void acpi_set_cpu_present_bit(AcpiCpuHotplug *g, CPUState *cpu,
63                                      bool *swtchd_to_modern)
64 {
65     CPUClass *k = CPU_GET_CLASS(cpu);
66     int64_t cpu_id;
67 
68     cpu_id = k->get_arch_id(cpu);
69     if ((cpu_id / 8) >= ACPI_GPE_PROC_LEN) {
70         object_property_set_bool(g->device, "cpu-hotplug-legacy", false,
71                                  &error_abort);
72         *swtchd_to_modern = true;
73         return;
74     }
75 
76     *swtchd_to_modern = false;
77     g->sts[cpu_id / 8] |= (1 << (cpu_id % 8));
78 }
79 
80 void legacy_acpi_cpu_plug_cb(HotplugHandler *hotplug_dev,
81                              AcpiCpuHotplug *g, DeviceState *dev, Error **errp)
82 {
83     bool swtchd_to_modern;
84     Error *local_err = NULL;
85 
86     acpi_set_cpu_present_bit(g, CPU(dev), &swtchd_to_modern);
87     if (swtchd_to_modern) {
88         /* propagate the hotplug to the modern interface */
89         hotplug_handler_plug(hotplug_dev, dev, &local_err);
90     } else {
91         acpi_send_event(DEVICE(hotplug_dev), ACPI_CPU_HOTPLUG_STATUS);
92     }
93 }
94 
95 void legacy_acpi_cpu_hotplug_init(MemoryRegion *parent, Object *owner,
96                                   AcpiCpuHotplug *gpe_cpu, uint16_t base)
97 {
98     CPUState *cpu;
99     bool swtchd_to_modern;
100 
101     memory_region_init_io(&gpe_cpu->io, owner, &AcpiCpuHotplug_ops,
102                           gpe_cpu, "acpi-cpu-hotplug", ACPI_GPE_PROC_LEN);
103     memory_region_add_subregion(parent, base, &gpe_cpu->io);
104     gpe_cpu->device = owner;
105 
106     CPU_FOREACH(cpu) {
107         acpi_set_cpu_present_bit(gpe_cpu, cpu, &swtchd_to_modern);
108     }
109 }
110 
111 void acpi_switch_to_modern_cphp(AcpiCpuHotplug *gpe_cpu,
112                                 CPUHotplugState *cpuhp_state,
113                                 uint16_t io_port)
114 {
115     MemoryRegion *parent = pci_address_space_io(PCI_DEVICE(gpe_cpu->device));
116 
117     memory_region_del_subregion(parent, &gpe_cpu->io);
118     cpu_hotplug_hw_init(parent, gpe_cpu->device, cpuhp_state, io_port);
119 }
120 
121 void build_legacy_cpu_hotplug_aml(Aml *ctx, MachineState *machine,
122                                   uint16_t io_base)
123 {
124     Aml *dev;
125     Aml *crs;
126     Aml *pkg;
127     Aml *field;
128     Aml *method;
129     Aml *if_ctx;
130     Aml *else_ctx;
131     int i, apic_idx;
132     Aml *sb_scope = aml_scope("_SB");
133     uint8_t madt_tmpl[8] = {0x00, 0x08, 0x00, 0x00, 0x00, 0, 0, 0};
134     Aml *cpu_id = aml_arg(1);
135     Aml *apic_id = aml_arg(0);
136     Aml *cpu_on = aml_local(0);
137     Aml *madt = aml_local(1);
138     Aml *cpus_map = aml_name(CPU_ON_BITMAP);
139     Aml *zero = aml_int(0);
140     Aml *one = aml_int(1);
141     MachineClass *mc = MACHINE_GET_CLASS(machine);
142     const CPUArchIdList *apic_ids = mc->possible_cpu_arch_ids(machine);
143     X86MachineState *x86ms = X86_MACHINE(machine);
144 
145     /*
146      * _MAT method - creates an madt apic buffer
147      * apic_id = Arg0 = Local APIC ID
148      * cpu_id  = Arg1 = Processor ID
149      * cpu_on = Local0 = CPON flag for this cpu
150      * madt = Local1 = Buffer (in madt apic form) to return
151      */
152     method = aml_method(CPU_MAT_METHOD, 2, AML_NOTSERIALIZED);
153     aml_append(method,
154         aml_store(aml_derefof(aml_index(cpus_map, apic_id)), cpu_on));
155     aml_append(method,
156         aml_store(aml_buffer(sizeof(madt_tmpl), madt_tmpl), madt));
157     /* Update the processor id, lapic id, and enable/disable status */
158     aml_append(method, aml_store(cpu_id, aml_index(madt, aml_int(2))));
159     aml_append(method, aml_store(apic_id, aml_index(madt, aml_int(3))));
160     aml_append(method, aml_store(cpu_on, aml_index(madt, aml_int(4))));
161     aml_append(method, aml_return(madt));
162     aml_append(sb_scope, method);
163 
164     /*
165      * _STA method - return ON status of cpu
166      * apic_id = Arg0 = Local APIC ID
167      * cpu_on = Local0 = CPON flag for this cpu
168      */
169     method = aml_method(CPU_STATUS_METHOD, 1, AML_NOTSERIALIZED);
170     aml_append(method,
171         aml_store(aml_derefof(aml_index(cpus_map, apic_id)), cpu_on));
172     if_ctx = aml_if(cpu_on);
173     {
174         aml_append(if_ctx, aml_return(aml_int(0xF)));
175     }
176     aml_append(method, if_ctx);
177     else_ctx = aml_else();
178     {
179         aml_append(else_ctx, aml_return(zero));
180     }
181     aml_append(method, else_ctx);
182     aml_append(sb_scope, method);
183 
184     method = aml_method(CPU_EJECT_METHOD, 2, AML_NOTSERIALIZED);
185     aml_append(method, aml_sleep(200));
186     aml_append(sb_scope, method);
187 
188     method = aml_method(CPU_SCAN_METHOD, 0, AML_NOTSERIALIZED);
189     {
190         Aml *while_ctx, *if_ctx2, *else_ctx2;
191         Aml *bus_check_evt = aml_int(1);
192         Aml *remove_evt = aml_int(3);
193         Aml *status_map = aml_local(5); /* Local5 = active cpu bitmap */
194         Aml *byte = aml_local(2); /* Local2 = last read byte from bitmap */
195         Aml *idx = aml_local(0); /* Processor ID / APIC ID iterator */
196         Aml *is_cpu_on = aml_local(1); /* Local1 = CPON flag for cpu */
197         Aml *status = aml_local(3); /* Local3 = active state for cpu */
198 
199         aml_append(method, aml_store(aml_name(CPU_STATUS_MAP), status_map));
200         aml_append(method, aml_store(zero, byte));
201         aml_append(method, aml_store(zero, idx));
202 
203         /* While (idx < SizeOf(CPON)) */
204         while_ctx = aml_while(aml_lless(idx, aml_sizeof(cpus_map)));
205         aml_append(while_ctx,
206             aml_store(aml_derefof(aml_index(cpus_map, idx)), is_cpu_on));
207 
208         if_ctx = aml_if(aml_and(idx, aml_int(0x07), NULL));
209         {
210             /* Shift down previously read bitmap byte */
211             aml_append(if_ctx, aml_shiftright(byte, one, byte));
212         }
213         aml_append(while_ctx, if_ctx);
214 
215         else_ctx = aml_else();
216         {
217             /* Read next byte from cpu bitmap */
218             aml_append(else_ctx, aml_store(aml_derefof(aml_index(status_map,
219                        aml_shiftright(idx, aml_int(3), NULL))), byte));
220         }
221         aml_append(while_ctx, else_ctx);
222 
223         aml_append(while_ctx, aml_store(aml_and(byte, one, NULL), status));
224         if_ctx = aml_if(aml_lnot(aml_equal(is_cpu_on, status)));
225         {
226             /* State change - update CPON with new state */
227             aml_append(if_ctx, aml_store(status, aml_index(cpus_map, idx)));
228             if_ctx2 = aml_if(aml_equal(status, one));
229             {
230                 aml_append(if_ctx2,
231                     aml_call2(AML_NOTIFY_METHOD, idx, bus_check_evt));
232             }
233             aml_append(if_ctx, if_ctx2);
234             else_ctx2 = aml_else();
235             {
236                 aml_append(else_ctx2,
237                     aml_call2(AML_NOTIFY_METHOD, idx, remove_evt));
238             }
239         }
240         aml_append(if_ctx, else_ctx2);
241         aml_append(while_ctx, if_ctx);
242 
243         aml_append(while_ctx, aml_increment(idx)); /* go to next cpu */
244         aml_append(method, while_ctx);
245     }
246     aml_append(sb_scope, method);
247 
248     /* The current AML generator can cover the APIC ID range [0..255],
249      * inclusive, for VCPU hotplug. */
250     QEMU_BUILD_BUG_ON(ACPI_CPU_HOTPLUG_ID_LIMIT > 256);
251     if (x86ms->apic_id_limit > ACPI_CPU_HOTPLUG_ID_LIMIT) {
252         error_report("max_cpus is too large. APIC ID of last CPU is %u",
253                      x86ms->apic_id_limit - 1);
254         exit(1);
255     }
256 
257     /* create PCI0.PRES device and its _CRS to reserve CPU hotplug MMIO */
258     dev = aml_device("PCI0." stringify(CPU_HOTPLUG_RESOURCE_DEVICE));
259     aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0A06")));
260     aml_append(dev,
261         aml_name_decl("_UID", aml_string("CPU Hotplug resources"))
262     );
263     /* device present, functioning, decoding, not shown in UI */
264     aml_append(dev, aml_name_decl("_STA", aml_int(0xB)));
265     crs = aml_resource_template();
266     aml_append(crs,
267         aml_io(AML_DECODE16, io_base, io_base, 1, ACPI_GPE_PROC_LEN)
268     );
269     aml_append(dev, aml_name_decl("_CRS", crs));
270     aml_append(sb_scope, dev);
271     /* declare CPU hotplug MMIO region and PRS field to access it */
272     aml_append(sb_scope, aml_operation_region(
273         "PRST", AML_SYSTEM_IO, aml_int(io_base), ACPI_GPE_PROC_LEN));
274     field = aml_field("PRST", AML_BYTE_ACC, AML_NOLOCK, AML_PRESERVE);
275     aml_append(field, aml_named_field("PRS", 256));
276     aml_append(sb_scope, field);
277 
278     /* build Processor object for each processor */
279     for (i = 0; i < apic_ids->len; i++) {
280         int cpu_apic_id = apic_ids->cpus[i].arch_id;
281 
282         assert(cpu_apic_id < ACPI_CPU_HOTPLUG_ID_LIMIT);
283 
284         dev = aml_processor(i, 0, 0, "CP%.02X", cpu_apic_id);
285 
286         method = aml_method("_MAT", 0, AML_NOTSERIALIZED);
287         aml_append(method,
288             aml_return(aml_call2(CPU_MAT_METHOD,
289                                  aml_int(cpu_apic_id), aml_int(i))
290         ));
291         aml_append(dev, method);
292 
293         method = aml_method("_STA", 0, AML_NOTSERIALIZED);
294         aml_append(method,
295             aml_return(aml_call1(CPU_STATUS_METHOD, aml_int(cpu_apic_id))));
296         aml_append(dev, method);
297 
298         method = aml_method("_EJ0", 1, AML_NOTSERIALIZED);
299         aml_append(method,
300             aml_return(aml_call2(CPU_EJECT_METHOD, aml_int(cpu_apic_id),
301                 aml_arg(0)))
302         );
303         aml_append(dev, method);
304 
305         aml_append(sb_scope, dev);
306     }
307 
308     /* build this code:
309      *   Method(NTFY, 2) {If (LEqual(Arg0, 0x00)) {Notify(CP00, Arg1)} ...}
310      */
311     /* Arg0 = APIC ID */
312     method = aml_method(AML_NOTIFY_METHOD, 2, AML_NOTSERIALIZED);
313     for (i = 0; i < apic_ids->len; i++) {
314         int cpu_apic_id = apic_ids->cpus[i].arch_id;
315 
316         if_ctx = aml_if(aml_equal(aml_arg(0), aml_int(cpu_apic_id)));
317         aml_append(if_ctx,
318             aml_notify(aml_name("CP%.02X", cpu_apic_id), aml_arg(1))
319         );
320         aml_append(method, if_ctx);
321     }
322     aml_append(sb_scope, method);
323 
324     /* build "Name(CPON, Package() { One, One, ..., Zero, Zero, ... })"
325      *
326      * Note: The ability to create variable-sized packages was first
327      * introduced in ACPI 2.0. ACPI 1.0 only allowed fixed-size packages
328      * ith up to 255 elements. Windows guests up to win2k8 fail when
329      * VarPackageOp is used.
330      */
331     pkg = x86ms->apic_id_limit <= 255 ? aml_package(x86ms->apic_id_limit) :
332                                         aml_varpackage(x86ms->apic_id_limit);
333 
334     for (i = 0, apic_idx = 0; i < apic_ids->len; i++) {
335         int cpu_apic_id = apic_ids->cpus[i].arch_id;
336 
337         for (; apic_idx < cpu_apic_id; apic_idx++) {
338             aml_append(pkg, aml_int(0));
339         }
340         aml_append(pkg, aml_int(apic_ids->cpus[i].cpu ? 1 : 0));
341         apic_idx = cpu_apic_id + 1;
342     }
343     aml_append(sb_scope, aml_name_decl(CPU_ON_BITMAP, pkg));
344     aml_append(ctx, sb_scope);
345 
346     method = aml_method("\\_GPE._E02", 0, AML_NOTSERIALIZED);
347     aml_append(method, aml_call0("\\_SB." CPU_SCAN_METHOD));
348     aml_append(ctx, method);
349 }
350