xref: /qemu/hw/acpi/cpu_hotplug.c (revision 9be38598) 
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/hw.h"
14 #include "hw/acpi/cpu_hotplug.h"
15 #include "qapi/error.h"
16 #include "qom/cpu.h"
17 #include "hw/i386/pc.h"
18 
19 #define CPU_EJECT_METHOD "CPEJ"
20 #define CPU_MAT_METHOD "CPMA"
21 #define CPU_ON_BITMAP "CPON"
22 #define CPU_STATUS_METHOD "CPST"
23 #define CPU_STATUS_MAP "PRS"
24 #define CPU_SCAN_METHOD "PRSC"
25 
26 static uint64_t cpu_status_read(void *opaque, hwaddr addr, unsigned int size)
27 {
28     AcpiCpuHotplug *cpus = opaque;
29     uint64_t val = cpus->sts[addr];
30 
31     return val;
32 }
33 
34 static void cpu_status_write(void *opaque, hwaddr addr, uint64_t data,
35                              unsigned int size)
36 {
37     /* TODO: implement VCPU removal on guest signal that CPU can be removed */
38 }
39 
40 static const MemoryRegionOps AcpiCpuHotplug_ops = {
41     .read = cpu_status_read,
42     .write = cpu_status_write,
43     .endianness = DEVICE_LITTLE_ENDIAN,
44     .valid = {
45         .min_access_size = 1,
46         .max_access_size = 1,
47     },
48 };
49 
50 static void acpi_set_cpu_present_bit(AcpiCpuHotplug *g, CPUState *cpu,
51                                      Error **errp)
52 {
53     CPUClass *k = CPU_GET_CLASS(cpu);
54     int64_t cpu_id;
55 
56     cpu_id = k->get_arch_id(cpu);
57     if ((cpu_id / 8) >= ACPI_GPE_PROC_LEN) {
58         error_setg(errp, "acpi: invalid cpu id: %" PRIi64, cpu_id);
59         return;
60     }
61 
62     g->sts[cpu_id / 8] |= (1 << (cpu_id % 8));
63 }
64 
65 void legacy_acpi_cpu_plug_cb(HotplugHandler *hotplug_dev,
66                              AcpiCpuHotplug *g, DeviceState *dev, Error **errp)
67 {
68     acpi_set_cpu_present_bit(g, CPU(dev), errp);
69     if (*errp != NULL) {
70         return;
71     }
72     acpi_send_event(DEVICE(hotplug_dev), ACPI_CPU_HOTPLUG_STATUS);
73 }
74 
75 void legacy_acpi_cpu_hotplug_init(MemoryRegion *parent, Object *owner,
76                                   AcpiCpuHotplug *gpe_cpu, uint16_t base)
77 {
78     CPUState *cpu;
79 
80     CPU_FOREACH(cpu) {
81         acpi_set_cpu_present_bit(gpe_cpu, cpu, &error_abort);
82     }
83     memory_region_init_io(&gpe_cpu->io, owner, &AcpiCpuHotplug_ops,
84                           gpe_cpu, "acpi-cpu-hotplug", ACPI_GPE_PROC_LEN);
85     memory_region_add_subregion(parent, base, &gpe_cpu->io);
86 }
87 
88 void build_legacy_cpu_hotplug_aml(Aml *ctx, MachineState *machine,
89                                   uint16_t io_base)
90 {
91     Aml *dev;
92     Aml *crs;
93     Aml *pkg;
94     Aml *field;
95     Aml *method;
96     Aml *if_ctx;
97     Aml *else_ctx;
98     int i, apic_idx;
99     Aml *sb_scope = aml_scope("_SB");
100     uint8_t madt_tmpl[8] = {0x00, 0x08, 0x00, 0x00, 0x00, 0, 0, 0};
101     Aml *cpu_id = aml_arg(1);
102     Aml *apic_id = aml_arg(0);
103     Aml *cpu_on = aml_local(0);
104     Aml *madt = aml_local(1);
105     Aml *cpus_map = aml_name(CPU_ON_BITMAP);
106     Aml *zero = aml_int(0);
107     Aml *one = aml_int(1);
108     MachineClass *mc = MACHINE_GET_CLASS(machine);
109     CPUArchIdList *apic_ids = mc->possible_cpu_arch_ids(machine);
110     PCMachineState *pcms = PC_MACHINE(machine);
111 
112     /*
113      * _MAT method - creates an madt apic buffer
114      * apic_id = Arg0 = Local APIC ID
115      * cpu_id  = Arg1 = Processor ID
116      * cpu_on = Local0 = CPON flag for this cpu
117      * madt = Local1 = Buffer (in madt apic form) to return
118      */
119     method = aml_method(CPU_MAT_METHOD, 2, AML_NOTSERIALIZED);
120     aml_append(method,
121         aml_store(aml_derefof(aml_index(cpus_map, apic_id)), cpu_on));
122     aml_append(method,
123         aml_store(aml_buffer(sizeof(madt_tmpl), madt_tmpl), madt));
124     /* Update the processor id, lapic id, and enable/disable status */
125     aml_append(method, aml_store(cpu_id, aml_index(madt, aml_int(2))));
126     aml_append(method, aml_store(apic_id, aml_index(madt, aml_int(3))));
127     aml_append(method, aml_store(cpu_on, aml_index(madt, aml_int(4))));
128     aml_append(method, aml_return(madt));
129     aml_append(sb_scope, method);
130 
131     /*
132      * _STA method - return ON status of cpu
133      * apic_id = Arg0 = Local APIC ID
134      * cpu_on = Local0 = CPON flag for this cpu
135      */
136     method = aml_method(CPU_STATUS_METHOD, 1, AML_NOTSERIALIZED);
137     aml_append(method,
138         aml_store(aml_derefof(aml_index(cpus_map, apic_id)), cpu_on));
139     if_ctx = aml_if(cpu_on);
140     {
141         aml_append(if_ctx, aml_return(aml_int(0xF)));
142     }
143     aml_append(method, if_ctx);
144     else_ctx = aml_else();
145     {
146         aml_append(else_ctx, aml_return(zero));
147     }
148     aml_append(method, else_ctx);
149     aml_append(sb_scope, method);
150 
151     method = aml_method(CPU_EJECT_METHOD, 2, AML_NOTSERIALIZED);
152     aml_append(method, aml_sleep(200));
153     aml_append(sb_scope, method);
154 
155     method = aml_method(CPU_SCAN_METHOD, 0, AML_NOTSERIALIZED);
156     {
157         Aml *while_ctx, *if_ctx2, *else_ctx2;
158         Aml *bus_check_evt = aml_int(1);
159         Aml *remove_evt = aml_int(3);
160         Aml *status_map = aml_local(5); /* Local5 = active cpu bitmap */
161         Aml *byte = aml_local(2); /* Local2 = last read byte from bitmap */
162         Aml *idx = aml_local(0); /* Processor ID / APIC ID iterator */
163         Aml *is_cpu_on = aml_local(1); /* Local1 = CPON flag for cpu */
164         Aml *status = aml_local(3); /* Local3 = active state for cpu */
165 
166         aml_append(method, aml_store(aml_name(CPU_STATUS_MAP), status_map));
167         aml_append(method, aml_store(zero, byte));
168         aml_append(method, aml_store(zero, idx));
169 
170         /* While (idx < SizeOf(CPON)) */
171         while_ctx = aml_while(aml_lless(idx, aml_sizeof(cpus_map)));
172         aml_append(while_ctx,
173             aml_store(aml_derefof(aml_index(cpus_map, idx)), is_cpu_on));
174 
175         if_ctx = aml_if(aml_and(idx, aml_int(0x07), NULL));
176         {
177             /* Shift down previously read bitmap byte */
178             aml_append(if_ctx, aml_shiftright(byte, one, byte));
179         }
180         aml_append(while_ctx, if_ctx);
181 
182         else_ctx = aml_else();
183         {
184             /* Read next byte from cpu bitmap */
185             aml_append(else_ctx, aml_store(aml_derefof(aml_index(status_map,
186                        aml_shiftright(idx, aml_int(3), NULL))), byte));
187         }
188         aml_append(while_ctx, else_ctx);
189 
190         aml_append(while_ctx, aml_store(aml_and(byte, one, NULL), status));
191         if_ctx = aml_if(aml_lnot(aml_equal(is_cpu_on, status)));
192         {
193             /* State change - update CPON with new state */
194             aml_append(if_ctx, aml_store(status, aml_index(cpus_map, idx)));
195             if_ctx2 = aml_if(aml_equal(status, one));
196             {
197                 aml_append(if_ctx2,
198                     aml_call2(AML_NOTIFY_METHOD, idx, bus_check_evt));
199             }
200             aml_append(if_ctx, if_ctx2);
201             else_ctx2 = aml_else();
202             {
203                 aml_append(else_ctx2,
204                     aml_call2(AML_NOTIFY_METHOD, idx, remove_evt));
205             }
206         }
207         aml_append(if_ctx, else_ctx2);
208         aml_append(while_ctx, if_ctx);
209 
210         aml_append(while_ctx, aml_increment(idx)); /* go to next cpu */
211         aml_append(method, while_ctx);
212     }
213     aml_append(sb_scope, method);
214 
215     /* The current AML generator can cover the APIC ID range [0..255],
216      * inclusive, for VCPU hotplug. */
217     QEMU_BUILD_BUG_ON(ACPI_CPU_HOTPLUG_ID_LIMIT > 256);
218     g_assert(pcms->apic_id_limit <= ACPI_CPU_HOTPLUG_ID_LIMIT);
219 
220     /* create PCI0.PRES device and its _CRS to reserve CPU hotplug MMIO */
221     dev = aml_device("PCI0." stringify(CPU_HOTPLUG_RESOURCE_DEVICE));
222     aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0A06")));
223     aml_append(dev,
224         aml_name_decl("_UID", aml_string("CPU Hotplug resources"))
225     );
226     /* device present, functioning, decoding, not shown in UI */
227     aml_append(dev, aml_name_decl("_STA", aml_int(0xB)));
228     crs = aml_resource_template();
229     aml_append(crs,
230         aml_io(AML_DECODE16, io_base, io_base, 1, ACPI_GPE_PROC_LEN)
231     );
232     aml_append(dev, aml_name_decl("_CRS", crs));
233     aml_append(sb_scope, dev);
234     /* declare CPU hotplug MMIO region and PRS field to access it */
235     aml_append(sb_scope, aml_operation_region(
236         "PRST", AML_SYSTEM_IO, aml_int(io_base), ACPI_GPE_PROC_LEN));
237     field = aml_field("PRST", AML_BYTE_ACC, AML_NOLOCK, AML_PRESERVE);
238     aml_append(field, aml_named_field("PRS", 256));
239     aml_append(sb_scope, field);
240 
241     /* build Processor object for each processor */
242     for (i = 0; i < apic_ids->len; i++) {
243         int apic_id = apic_ids->cpus[i].arch_id;
244 
245         assert(apic_id < ACPI_CPU_HOTPLUG_ID_LIMIT);
246 
247         dev = aml_processor(i, 0, 0, "CP%.02X", apic_id);
248 
249         method = aml_method("_MAT", 0, AML_NOTSERIALIZED);
250         aml_append(method,
251             aml_return(aml_call2(CPU_MAT_METHOD, aml_int(apic_id), aml_int(i))
252         ));
253         aml_append(dev, method);
254 
255         method = aml_method("_STA", 0, AML_NOTSERIALIZED);
256         aml_append(method,
257             aml_return(aml_call1(CPU_STATUS_METHOD, aml_int(apic_id))));
258         aml_append(dev, method);
259 
260         method = aml_method("_EJ0", 1, AML_NOTSERIALIZED);
261         aml_append(method,
262             aml_return(aml_call2(CPU_EJECT_METHOD, aml_int(apic_id),
263                 aml_arg(0)))
264         );
265         aml_append(dev, method);
266 
267         aml_append(sb_scope, dev);
268     }
269 
270     /* build this code:
271      *   Method(NTFY, 2) {If (LEqual(Arg0, 0x00)) {Notify(CP00, Arg1)} ...}
272      */
273     /* Arg0 = APIC ID */
274     method = aml_method(AML_NOTIFY_METHOD, 2, AML_NOTSERIALIZED);
275     for (i = 0; i < apic_ids->len; i++) {
276         int apic_id = apic_ids->cpus[i].arch_id;
277 
278         if_ctx = aml_if(aml_equal(aml_arg(0), aml_int(apic_id)));
279         aml_append(if_ctx,
280             aml_notify(aml_name("CP%.02X", apic_id), aml_arg(1))
281         );
282         aml_append(method, if_ctx);
283     }
284     aml_append(sb_scope, method);
285 
286     /* build "Name(CPON, Package() { One, One, ..., Zero, Zero, ... })"
287      *
288      * Note: The ability to create variable-sized packages was first
289      * introduced in ACPI 2.0. ACPI 1.0 only allowed fixed-size packages
290      * ith up to 255 elements. Windows guests up to win2k8 fail when
291      * VarPackageOp is used.
292      */
293     pkg = pcms->apic_id_limit <= 255 ? aml_package(pcms->apic_id_limit) :
294                                        aml_varpackage(pcms->apic_id_limit);
295 
296     for (i = 0, apic_idx = 0; i < apic_ids->len; i++) {
297         int apic_id = apic_ids->cpus[i].arch_id;
298 
299         for (; apic_idx < apic_id; apic_idx++) {
300             aml_append(pkg, aml_int(0));
301         }
302         aml_append(pkg, aml_int(apic_ids->cpus[i].cpu ? 1 : 0));
303         apic_idx = apic_id + 1;
304     }
305     aml_append(sb_scope, aml_name_decl(CPU_ON_BITMAP, pkg));
306     g_free(apic_ids);
307 
308     aml_append(ctx, sb_scope);
309 
310     method = aml_method("\\_GPE._E02", 0, AML_NOTSERIALIZED);
311     aml_append(method, aml_call0("\\_SB." CPU_SCAN_METHOD));
312     aml_append(ctx, method);
313 }
314