xref: /openbmc/qemu/hw/acpi/cpu_hotplug.c (revision d2dfe0b5)
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 {
64     CPUClass *k = CPU_GET_CLASS(cpu);
65     int64_t cpu_id;
66 
67     cpu_id = k->get_arch_id(cpu);
68     if ((cpu_id / 8) >= ACPI_GPE_PROC_LEN) {
69         object_property_set_bool(g->device, "cpu-hotplug-legacy", false,
70                                  &error_abort);
71         return;
72     }
73 
74     g->sts[cpu_id / 8] |= (1 << (cpu_id % 8));
75 }
76 
77 void legacy_acpi_cpu_plug_cb(HotplugHandler *hotplug_dev,
78                              AcpiCpuHotplug *g, DeviceState *dev, Error **errp)
79 {
80     acpi_set_cpu_present_bit(g, CPU(dev));
81     acpi_send_event(DEVICE(hotplug_dev), ACPI_CPU_HOTPLUG_STATUS);
82 }
83 
84 void legacy_acpi_cpu_hotplug_init(MemoryRegion *parent, Object *owner,
85                                   AcpiCpuHotplug *gpe_cpu, uint16_t base)
86 {
87     CPUState *cpu;
88 
89     memory_region_init_io(&gpe_cpu->io, owner, &AcpiCpuHotplug_ops,
90                           gpe_cpu, "acpi-cpu-hotplug", ACPI_GPE_PROC_LEN);
91     memory_region_add_subregion(parent, base, &gpe_cpu->io);
92     gpe_cpu->device = owner;
93 
94     CPU_FOREACH(cpu) {
95         acpi_set_cpu_present_bit(gpe_cpu, cpu);
96     }
97 }
98 
99 void acpi_switch_to_modern_cphp(AcpiCpuHotplug *gpe_cpu,
100                                 CPUHotplugState *cpuhp_state,
101                                 uint16_t io_port)
102 {
103     MemoryRegion *parent = pci_address_space_io(PCI_DEVICE(gpe_cpu->device));
104 
105     memory_region_del_subregion(parent, &gpe_cpu->io);
106     cpu_hotplug_hw_init(parent, gpe_cpu->device, cpuhp_state, io_port);
107 }
108 
109 void build_legacy_cpu_hotplug_aml(Aml *ctx, MachineState *machine,
110                                   uint16_t io_base)
111 {
112     Aml *dev;
113     Aml *crs;
114     Aml *pkg;
115     Aml *field;
116     Aml *method;
117     Aml *if_ctx;
118     Aml *else_ctx;
119     int i, apic_idx;
120     Aml *sb_scope = aml_scope("_SB");
121     uint8_t madt_tmpl[8] = {0x00, 0x08, 0x00, 0x00, 0x00, 0, 0, 0};
122     Aml *cpu_id = aml_arg(1);
123     Aml *apic_id = aml_arg(0);
124     Aml *cpu_on = aml_local(0);
125     Aml *madt = aml_local(1);
126     Aml *cpus_map = aml_name(CPU_ON_BITMAP);
127     Aml *zero = aml_int(0);
128     Aml *one = aml_int(1);
129     MachineClass *mc = MACHINE_GET_CLASS(machine);
130     const CPUArchIdList *apic_ids = mc->possible_cpu_arch_ids(machine);
131     X86MachineState *x86ms = X86_MACHINE(machine);
132 
133     /*
134      * _MAT method - creates an madt apic buffer
135      * apic_id = Arg0 = Local APIC ID
136      * cpu_id  = Arg1 = Processor ID
137      * cpu_on = Local0 = CPON flag for this cpu
138      * madt = Local1 = Buffer (in madt apic form) to return
139      */
140     method = aml_method(CPU_MAT_METHOD, 2, AML_NOTSERIALIZED);
141     aml_append(method,
142         aml_store(aml_derefof(aml_index(cpus_map, apic_id)), cpu_on));
143     aml_append(method,
144         aml_store(aml_buffer(sizeof(madt_tmpl), madt_tmpl), madt));
145     /* Update the processor id, lapic id, and enable/disable status */
146     aml_append(method, aml_store(cpu_id, aml_index(madt, aml_int(2))));
147     aml_append(method, aml_store(apic_id, aml_index(madt, aml_int(3))));
148     aml_append(method, aml_store(cpu_on, aml_index(madt, aml_int(4))));
149     aml_append(method, aml_return(madt));
150     aml_append(sb_scope, method);
151 
152     /*
153      * _STA method - return ON status of cpu
154      * apic_id = Arg0 = Local APIC ID
155      * cpu_on = Local0 = CPON flag for this cpu
156      */
157     method = aml_method(CPU_STATUS_METHOD, 1, AML_NOTSERIALIZED);
158     aml_append(method,
159         aml_store(aml_derefof(aml_index(cpus_map, apic_id)), cpu_on));
160     if_ctx = aml_if(cpu_on);
161     {
162         aml_append(if_ctx, aml_return(aml_int(0xF)));
163     }
164     aml_append(method, if_ctx);
165     else_ctx = aml_else();
166     {
167         aml_append(else_ctx, aml_return(zero));
168     }
169     aml_append(method, else_ctx);
170     aml_append(sb_scope, method);
171 
172     method = aml_method(CPU_EJECT_METHOD, 2, AML_NOTSERIALIZED);
173     aml_append(method, aml_sleep(200));
174     aml_append(sb_scope, method);
175 
176     method = aml_method(CPU_SCAN_METHOD, 0, AML_NOTSERIALIZED);
177     {
178         Aml *while_ctx, *if_ctx2, *else_ctx2;
179         Aml *bus_check_evt = aml_int(1);
180         Aml *remove_evt = aml_int(3);
181         Aml *status_map = aml_local(5); /* Local5 = active cpu bitmap */
182         Aml *byte = aml_local(2); /* Local2 = last read byte from bitmap */
183         Aml *idx = aml_local(0); /* Processor ID / APIC ID iterator */
184         Aml *is_cpu_on = aml_local(1); /* Local1 = CPON flag for cpu */
185         Aml *status = aml_local(3); /* Local3 = active state for cpu */
186 
187         aml_append(method, aml_store(aml_name(CPU_STATUS_MAP), status_map));
188         aml_append(method, aml_store(zero, byte));
189         aml_append(method, aml_store(zero, idx));
190 
191         /* While (idx < SizeOf(CPON)) */
192         while_ctx = aml_while(aml_lless(idx, aml_sizeof(cpus_map)));
193         aml_append(while_ctx,
194             aml_store(aml_derefof(aml_index(cpus_map, idx)), is_cpu_on));
195 
196         if_ctx = aml_if(aml_and(idx, aml_int(0x07), NULL));
197         {
198             /* Shift down previously read bitmap byte */
199             aml_append(if_ctx, aml_shiftright(byte, one, byte));
200         }
201         aml_append(while_ctx, if_ctx);
202 
203         else_ctx = aml_else();
204         {
205             /* Read next byte from cpu bitmap */
206             aml_append(else_ctx, aml_store(aml_derefof(aml_index(status_map,
207                        aml_shiftright(idx, aml_int(3), NULL))), byte));
208         }
209         aml_append(while_ctx, else_ctx);
210 
211         aml_append(while_ctx, aml_store(aml_and(byte, one, NULL), status));
212         if_ctx = aml_if(aml_lnot(aml_equal(is_cpu_on, status)));
213         {
214             /* State change - update CPON with new state */
215             aml_append(if_ctx, aml_store(status, aml_index(cpus_map, idx)));
216             if_ctx2 = aml_if(aml_equal(status, one));
217             {
218                 aml_append(if_ctx2,
219                     aml_call2(AML_NOTIFY_METHOD, idx, bus_check_evt));
220             }
221             aml_append(if_ctx, if_ctx2);
222             else_ctx2 = aml_else();
223             {
224                 aml_append(else_ctx2,
225                     aml_call2(AML_NOTIFY_METHOD, idx, remove_evt));
226             }
227         }
228         aml_append(if_ctx, else_ctx2);
229         aml_append(while_ctx, if_ctx);
230 
231         aml_append(while_ctx, aml_increment(idx)); /* go to next cpu */
232         aml_append(method, while_ctx);
233     }
234     aml_append(sb_scope, method);
235 
236     /* The current AML generator can cover the APIC ID range [0..255],
237      * inclusive, for VCPU hotplug. */
238     QEMU_BUILD_BUG_ON(ACPI_CPU_HOTPLUG_ID_LIMIT > 256);
239     if (x86ms->apic_id_limit > ACPI_CPU_HOTPLUG_ID_LIMIT) {
240         error_report("max_cpus is too large. APIC ID of last CPU is %u",
241                      x86ms->apic_id_limit - 1);
242         exit(1);
243     }
244 
245     /* create PCI0.PRES device and its _CRS to reserve CPU hotplug MMIO */
246     dev = aml_device("PCI0." stringify(CPU_HOTPLUG_RESOURCE_DEVICE));
247     aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0A06")));
248     aml_append(dev,
249         aml_name_decl("_UID", aml_string("CPU Hotplug resources"))
250     );
251     /* device present, functioning, decoding, not shown in UI */
252     aml_append(dev, aml_name_decl("_STA", aml_int(0xB)));
253     crs = aml_resource_template();
254     aml_append(crs,
255         aml_io(AML_DECODE16, io_base, io_base, 1, ACPI_GPE_PROC_LEN)
256     );
257     aml_append(dev, aml_name_decl("_CRS", crs));
258     aml_append(sb_scope, dev);
259     /* declare CPU hotplug MMIO region and PRS field to access it */
260     aml_append(sb_scope, aml_operation_region(
261         "PRST", AML_SYSTEM_IO, aml_int(io_base), ACPI_GPE_PROC_LEN));
262     field = aml_field("PRST", AML_BYTE_ACC, AML_NOLOCK, AML_PRESERVE);
263     aml_append(field, aml_named_field("PRS", 256));
264     aml_append(sb_scope, field);
265 
266     /* build Processor object for each processor */
267     for (i = 0; i < apic_ids->len; i++) {
268         int apic_id = apic_ids->cpus[i].arch_id;
269 
270         assert(apic_id < ACPI_CPU_HOTPLUG_ID_LIMIT);
271 
272         dev = aml_processor(i, 0, 0, "CP%.02X", apic_id);
273 
274         method = aml_method("_MAT", 0, AML_NOTSERIALIZED);
275         aml_append(method,
276             aml_return(aml_call2(CPU_MAT_METHOD, aml_int(apic_id), aml_int(i))
277         ));
278         aml_append(dev, method);
279 
280         method = aml_method("_STA", 0, AML_NOTSERIALIZED);
281         aml_append(method,
282             aml_return(aml_call1(CPU_STATUS_METHOD, aml_int(apic_id))));
283         aml_append(dev, method);
284 
285         method = aml_method("_EJ0", 1, AML_NOTSERIALIZED);
286         aml_append(method,
287             aml_return(aml_call2(CPU_EJECT_METHOD, aml_int(apic_id),
288                 aml_arg(0)))
289         );
290         aml_append(dev, method);
291 
292         aml_append(sb_scope, dev);
293     }
294 
295     /* build this code:
296      *   Method(NTFY, 2) {If (LEqual(Arg0, 0x00)) {Notify(CP00, Arg1)} ...}
297      */
298     /* Arg0 = APIC ID */
299     method = aml_method(AML_NOTIFY_METHOD, 2, AML_NOTSERIALIZED);
300     for (i = 0; i < apic_ids->len; i++) {
301         int apic_id = apic_ids->cpus[i].arch_id;
302 
303         if_ctx = aml_if(aml_equal(aml_arg(0), aml_int(apic_id)));
304         aml_append(if_ctx,
305             aml_notify(aml_name("CP%.02X", apic_id), aml_arg(1))
306         );
307         aml_append(method, if_ctx);
308     }
309     aml_append(sb_scope, method);
310 
311     /* build "Name(CPON, Package() { One, One, ..., Zero, Zero, ... })"
312      *
313      * Note: The ability to create variable-sized packages was first
314      * introduced in ACPI 2.0. ACPI 1.0 only allowed fixed-size packages
315      * ith up to 255 elements. Windows guests up to win2k8 fail when
316      * VarPackageOp is used.
317      */
318     pkg = x86ms->apic_id_limit <= 255 ? aml_package(x86ms->apic_id_limit) :
319                                         aml_varpackage(x86ms->apic_id_limit);
320 
321     for (i = 0, apic_idx = 0; i < apic_ids->len; i++) {
322         int apic_id = apic_ids->cpus[i].arch_id;
323 
324         for (; apic_idx < apic_id; apic_idx++) {
325             aml_append(pkg, aml_int(0));
326         }
327         aml_append(pkg, aml_int(apic_ids->cpus[i].cpu ? 1 : 0));
328         apic_idx = apic_id + 1;
329     }
330     aml_append(sb_scope, aml_name_decl(CPU_ON_BITMAP, pkg));
331     aml_append(ctx, sb_scope);
332 
333     method = aml_method("\\_GPE._E02", 0, AML_NOTSERIALIZED);
334     aml_append(method, aml_call0("\\_SB." CPU_SCAN_METHOD));
335     aml_append(ctx, method);
336 }
337