xref: /openbmc/qemu/hw/acpi/cpu_hotplug.c (revision b917da4c)
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 "qom/cpu.h"
16 
17 static uint64_t cpu_status_read(void *opaque, hwaddr addr, unsigned int size)
18 {
19     AcpiCpuHotplug *cpus = opaque;
20     uint64_t val = cpus->sts[addr];
21 
22     return val;
23 }
24 
25 static void cpu_status_write(void *opaque, hwaddr addr, uint64_t data,
26                              unsigned int size)
27 {
28     /* TODO: implement VCPU removal on guest signal that CPU can be removed */
29 }
30 
31 static const MemoryRegionOps AcpiCpuHotplug_ops = {
32     .read = cpu_status_read,
33     .write = cpu_status_write,
34     .endianness = DEVICE_LITTLE_ENDIAN,
35     .valid = {
36         .min_access_size = 1,
37         .max_access_size = 1,
38     },
39 };
40 
41 static void acpi_set_cpu_present_bit(AcpiCpuHotplug *g, CPUState *cpu,
42                                      Error **errp)
43 {
44     CPUClass *k = CPU_GET_CLASS(cpu);
45     int64_t cpu_id;
46 
47     cpu_id = k->get_arch_id(cpu);
48     if ((cpu_id / 8) >= ACPI_GPE_PROC_LEN) {
49         error_setg(errp, "acpi: invalid cpu id: %" PRIi64, cpu_id);
50         return;
51     }
52 
53     g->sts[cpu_id / 8] |= (1 << (cpu_id % 8));
54 }
55 
56 void acpi_cpu_plug_cb(ACPIREGS *ar, qemu_irq irq,
57                       AcpiCpuHotplug *g, DeviceState *dev, Error **errp)
58 {
59     acpi_set_cpu_present_bit(g, CPU(dev), errp);
60     if (*errp != NULL) {
61         return;
62     }
63 
64     acpi_send_gpe_event(ar, irq, ACPI_CPU_HOTPLUG_STATUS);
65 }
66 
67 void acpi_cpu_hotplug_init(MemoryRegion *parent, Object *owner,
68                            AcpiCpuHotplug *gpe_cpu, uint16_t base)
69 {
70     CPUState *cpu;
71 
72     CPU_FOREACH(cpu) {
73         acpi_set_cpu_present_bit(gpe_cpu, cpu, &error_abort);
74     }
75     memory_region_init_io(&gpe_cpu->io, owner, &AcpiCpuHotplug_ops,
76                           gpe_cpu, "acpi-cpu-hotplug", ACPI_GPE_PROC_LEN);
77     memory_region_add_subregion(parent, base, &gpe_cpu->io);
78 }
79