xref: /openbmc/qemu/hw/acpi/cpu_hotplug.c (revision b91a0fa7)
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 = 1,
56     },
57 };
58 
59 static void acpi_set_cpu_present_bit(AcpiCpuHotplug *g, CPUState *cpu)
60 {
61     CPUClass *k = CPU_GET_CLASS(cpu);
62     int64_t cpu_id;
63 
64     cpu_id = k->get_arch_id(cpu);
65     if ((cpu_id / 8) >= ACPI_GPE_PROC_LEN) {
66         object_property_set_bool(g->device, "cpu-hotplug-legacy", false,
67                                  &error_abort);
68         return;
69     }
70 
71     g->sts[cpu_id / 8] |= (1 << (cpu_id % 8));
72 }
73 
74 void legacy_acpi_cpu_plug_cb(HotplugHandler *hotplug_dev,
75                              AcpiCpuHotplug *g, DeviceState *dev, Error **errp)
76 {
77     acpi_set_cpu_present_bit(g, CPU(dev));
78     acpi_send_event(DEVICE(hotplug_dev), ACPI_CPU_HOTPLUG_STATUS);
79 }
80 
81 void legacy_acpi_cpu_hotplug_init(MemoryRegion *parent, Object *owner,
82                                   AcpiCpuHotplug *gpe_cpu, uint16_t base)
83 {
84     CPUState *cpu;
85 
86     memory_region_init_io(&gpe_cpu->io, owner, &AcpiCpuHotplug_ops,
87                           gpe_cpu, "acpi-cpu-hotplug", ACPI_GPE_PROC_LEN);
88     memory_region_add_subregion(parent, base, &gpe_cpu->io);
89     gpe_cpu->device = owner;
90 
91     CPU_FOREACH(cpu) {
92         acpi_set_cpu_present_bit(gpe_cpu, cpu);
93     }
94 }
95 
96 void acpi_switch_to_modern_cphp(AcpiCpuHotplug *gpe_cpu,
97                                 CPUHotplugState *cpuhp_state,
98                                 uint16_t io_port)
99 {
100     MemoryRegion *parent = pci_address_space_io(PCI_DEVICE(gpe_cpu->device));
101 
102     memory_region_del_subregion(parent, &gpe_cpu->io);
103     cpu_hotplug_hw_init(parent, gpe_cpu->device, cpuhp_state, io_port);
104 }
105 
106 void build_legacy_cpu_hotplug_aml(Aml *ctx, MachineState *machine,
107                                   uint16_t io_base)
108 {
109     Aml *dev;
110     Aml *crs;
111     Aml *pkg;
112     Aml *field;
113     Aml *method;
114     Aml *if_ctx;
115     Aml *else_ctx;
116     int i, apic_idx;
117     Aml *sb_scope = aml_scope("_SB");
118     uint8_t madt_tmpl[8] = {0x00, 0x08, 0x00, 0x00, 0x00, 0, 0, 0};
119     Aml *cpu_id = aml_arg(1);
120     Aml *apic_id = aml_arg(0);
121     Aml *cpu_on = aml_local(0);
122     Aml *madt = aml_local(1);
123     Aml *cpus_map = aml_name(CPU_ON_BITMAP);
124     Aml *zero = aml_int(0);
125     Aml *one = aml_int(1);
126     MachineClass *mc = MACHINE_GET_CLASS(machine);
127     const CPUArchIdList *apic_ids = mc->possible_cpu_arch_ids(machine);
128     X86MachineState *x86ms = X86_MACHINE(machine);
129 
130     /*
131      * _MAT method - creates an madt apic buffer
132      * apic_id = Arg0 = Local APIC ID
133      * cpu_id  = Arg1 = Processor ID
134      * cpu_on = Local0 = CPON flag for this cpu
135      * madt = Local1 = Buffer (in madt apic form) to return
136      */
137     method = aml_method(CPU_MAT_METHOD, 2, AML_NOTSERIALIZED);
138     aml_append(method,
139         aml_store(aml_derefof(aml_index(cpus_map, apic_id)), cpu_on));
140     aml_append(method,
141         aml_store(aml_buffer(sizeof(madt_tmpl), madt_tmpl), madt));
142     /* Update the processor id, lapic id, and enable/disable status */
143     aml_append(method, aml_store(cpu_id, aml_index(madt, aml_int(2))));
144     aml_append(method, aml_store(apic_id, aml_index(madt, aml_int(3))));
145     aml_append(method, aml_store(cpu_on, aml_index(madt, aml_int(4))));
146     aml_append(method, aml_return(madt));
147     aml_append(sb_scope, method);
148 
149     /*
150      * _STA method - return ON status of cpu
151      * apic_id = Arg0 = Local APIC ID
152      * cpu_on = Local0 = CPON flag for this cpu
153      */
154     method = aml_method(CPU_STATUS_METHOD, 1, AML_NOTSERIALIZED);
155     aml_append(method,
156         aml_store(aml_derefof(aml_index(cpus_map, apic_id)), cpu_on));
157     if_ctx = aml_if(cpu_on);
158     {
159         aml_append(if_ctx, aml_return(aml_int(0xF)));
160     }
161     aml_append(method, if_ctx);
162     else_ctx = aml_else();
163     {
164         aml_append(else_ctx, aml_return(zero));
165     }
166     aml_append(method, else_ctx);
167     aml_append(sb_scope, method);
168 
169     method = aml_method(CPU_EJECT_METHOD, 2, AML_NOTSERIALIZED);
170     aml_append(method, aml_sleep(200));
171     aml_append(sb_scope, method);
172 
173     method = aml_method(CPU_SCAN_METHOD, 0, AML_NOTSERIALIZED);
174     {
175         Aml *while_ctx, *if_ctx2, *else_ctx2;
176         Aml *bus_check_evt = aml_int(1);
177         Aml *remove_evt = aml_int(3);
178         Aml *status_map = aml_local(5); /* Local5 = active cpu bitmap */
179         Aml *byte = aml_local(2); /* Local2 = last read byte from bitmap */
180         Aml *idx = aml_local(0); /* Processor ID / APIC ID iterator */
181         Aml *is_cpu_on = aml_local(1); /* Local1 = CPON flag for cpu */
182         Aml *status = aml_local(3); /* Local3 = active state for cpu */
183 
184         aml_append(method, aml_store(aml_name(CPU_STATUS_MAP), status_map));
185         aml_append(method, aml_store(zero, byte));
186         aml_append(method, aml_store(zero, idx));
187 
188         /* While (idx < SizeOf(CPON)) */
189         while_ctx = aml_while(aml_lless(idx, aml_sizeof(cpus_map)));
190         aml_append(while_ctx,
191             aml_store(aml_derefof(aml_index(cpus_map, idx)), is_cpu_on));
192 
193         if_ctx = aml_if(aml_and(idx, aml_int(0x07), NULL));
194         {
195             /* Shift down previously read bitmap byte */
196             aml_append(if_ctx, aml_shiftright(byte, one, byte));
197         }
198         aml_append(while_ctx, if_ctx);
199 
200         else_ctx = aml_else();
201         {
202             /* Read next byte from cpu bitmap */
203             aml_append(else_ctx, aml_store(aml_derefof(aml_index(status_map,
204                        aml_shiftright(idx, aml_int(3), NULL))), byte));
205         }
206         aml_append(while_ctx, else_ctx);
207 
208         aml_append(while_ctx, aml_store(aml_and(byte, one, NULL), status));
209         if_ctx = aml_if(aml_lnot(aml_equal(is_cpu_on, status)));
210         {
211             /* State change - update CPON with new state */
212             aml_append(if_ctx, aml_store(status, aml_index(cpus_map, idx)));
213             if_ctx2 = aml_if(aml_equal(status, one));
214             {
215                 aml_append(if_ctx2,
216                     aml_call2(AML_NOTIFY_METHOD, idx, bus_check_evt));
217             }
218             aml_append(if_ctx, if_ctx2);
219             else_ctx2 = aml_else();
220             {
221                 aml_append(else_ctx2,
222                     aml_call2(AML_NOTIFY_METHOD, idx, remove_evt));
223             }
224         }
225         aml_append(if_ctx, else_ctx2);
226         aml_append(while_ctx, if_ctx);
227 
228         aml_append(while_ctx, aml_increment(idx)); /* go to next cpu */
229         aml_append(method, while_ctx);
230     }
231     aml_append(sb_scope, method);
232 
233     /* The current AML generator can cover the APIC ID range [0..255],
234      * inclusive, for VCPU hotplug. */
235     QEMU_BUILD_BUG_ON(ACPI_CPU_HOTPLUG_ID_LIMIT > 256);
236     if (x86ms->apic_id_limit > ACPI_CPU_HOTPLUG_ID_LIMIT) {
237         error_report("max_cpus is too large. APIC ID of last CPU is %u",
238                      x86ms->apic_id_limit - 1);
239         exit(1);
240     }
241 
242     /* create PCI0.PRES device and its _CRS to reserve CPU hotplug MMIO */
243     dev = aml_device("PCI0." stringify(CPU_HOTPLUG_RESOURCE_DEVICE));
244     aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0A06")));
245     aml_append(dev,
246         aml_name_decl("_UID", aml_string("CPU Hotplug resources"))
247     );
248     /* device present, functioning, decoding, not shown in UI */
249     aml_append(dev, aml_name_decl("_STA", aml_int(0xB)));
250     crs = aml_resource_template();
251     aml_append(crs,
252         aml_io(AML_DECODE16, io_base, io_base, 1, ACPI_GPE_PROC_LEN)
253     );
254     aml_append(dev, aml_name_decl("_CRS", crs));
255     aml_append(sb_scope, dev);
256     /* declare CPU hotplug MMIO region and PRS field to access it */
257     aml_append(sb_scope, aml_operation_region(
258         "PRST", AML_SYSTEM_IO, aml_int(io_base), ACPI_GPE_PROC_LEN));
259     field = aml_field("PRST", AML_BYTE_ACC, AML_NOLOCK, AML_PRESERVE);
260     aml_append(field, aml_named_field("PRS", 256));
261     aml_append(sb_scope, field);
262 
263     /* build Processor object for each processor */
264     for (i = 0; i < apic_ids->len; i++) {
265         int apic_id = apic_ids->cpus[i].arch_id;
266 
267         assert(apic_id < ACPI_CPU_HOTPLUG_ID_LIMIT);
268 
269         dev = aml_processor(i, 0, 0, "CP%.02X", apic_id);
270 
271         method = aml_method("_MAT", 0, AML_NOTSERIALIZED);
272         aml_append(method,
273             aml_return(aml_call2(CPU_MAT_METHOD, aml_int(apic_id), aml_int(i))
274         ));
275         aml_append(dev, method);
276 
277         method = aml_method("_STA", 0, AML_NOTSERIALIZED);
278         aml_append(method,
279             aml_return(aml_call1(CPU_STATUS_METHOD, aml_int(apic_id))));
280         aml_append(dev, method);
281 
282         method = aml_method("_EJ0", 1, AML_NOTSERIALIZED);
283         aml_append(method,
284             aml_return(aml_call2(CPU_EJECT_METHOD, aml_int(apic_id),
285                 aml_arg(0)))
286         );
287         aml_append(dev, method);
288 
289         aml_append(sb_scope, dev);
290     }
291 
292     /* build this code:
293      *   Method(NTFY, 2) {If (LEqual(Arg0, 0x00)) {Notify(CP00, Arg1)} ...}
294      */
295     /* Arg0 = APIC ID */
296     method = aml_method(AML_NOTIFY_METHOD, 2, AML_NOTSERIALIZED);
297     for (i = 0; i < apic_ids->len; i++) {
298         int apic_id = apic_ids->cpus[i].arch_id;
299 
300         if_ctx = aml_if(aml_equal(aml_arg(0), aml_int(apic_id)));
301         aml_append(if_ctx,
302             aml_notify(aml_name("CP%.02X", apic_id), aml_arg(1))
303         );
304         aml_append(method, if_ctx);
305     }
306     aml_append(sb_scope, method);
307 
308     /* build "Name(CPON, Package() { One, One, ..., Zero, Zero, ... })"
309      *
310      * Note: The ability to create variable-sized packages was first
311      * introduced in ACPI 2.0. ACPI 1.0 only allowed fixed-size packages
312      * ith up to 255 elements. Windows guests up to win2k8 fail when
313      * VarPackageOp is used.
314      */
315     pkg = x86ms->apic_id_limit <= 255 ? aml_package(x86ms->apic_id_limit) :
316                                         aml_varpackage(x86ms->apic_id_limit);
317 
318     for (i = 0, apic_idx = 0; i < apic_ids->len; i++) {
319         int apic_id = apic_ids->cpus[i].arch_id;
320 
321         for (; apic_idx < apic_id; apic_idx++) {
322             aml_append(pkg, aml_int(0));
323         }
324         aml_append(pkg, aml_int(apic_ids->cpus[i].cpu ? 1 : 0));
325         apic_idx = apic_id + 1;
326     }
327     aml_append(sb_scope, aml_name_decl(CPU_ON_BITMAP, pkg));
328     aml_append(ctx, sb_scope);
329 
330     method = aml_method("\\_GPE._E02", 0, AML_NOTSERIALIZED);
331     aml_append(method, aml_call0("\\_SB." CPU_SCAN_METHOD));
332     aml_append(ctx, method);
333 }
334