xref: /qemu/hw/acpi/cpu_hotplug.c (revision 1438eff3)
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 
16 static uint64_t cpu_status_read(void *opaque, hwaddr addr, unsigned int size)
17 {
18     AcpiCpuHotplug *cpus = opaque;
19     uint64_t val = cpus->sts[addr];
20 
21     return val;
22 }
23 
24 static void cpu_status_write(void *opaque, hwaddr addr, uint64_t data,
25                              unsigned int size)
26 {
27     /* TODO: implement VCPU removal on guest signal that CPU can be removed */
28 }
29 
30 static const MemoryRegionOps AcpiCpuHotplug_ops = {
31     .read = cpu_status_read,
32     .write = cpu_status_write,
33     .endianness = DEVICE_LITTLE_ENDIAN,
34     .valid = {
35         .min_access_size = 1,
36         .max_access_size = 1,
37     },
38 };
39 
40 static void acpi_set_cpu_present_bit(AcpiCpuHotplug *g, CPUState *cpu,
41                                      Error **errp)
42 {
43     CPUClass *k = CPU_GET_CLASS(cpu);
44     int64_t cpu_id;
45 
46     cpu_id = k->get_arch_id(cpu);
47     if ((cpu_id / 8) >= ACPI_GPE_PROC_LEN) {
48         error_setg(errp, "acpi: invalid cpu id: %" PRIi64, cpu_id);
49         return;
50     }
51 
52     g->sts[cpu_id / 8] |= (1 << (cpu_id % 8));
53 }
54 
55 void acpi_cpu_plug_cb(ACPIREGS *ar, qemu_irq irq,
56                       AcpiCpuHotplug *g, DeviceState *dev, Error **errp)
57 {
58     acpi_set_cpu_present_bit(g, CPU(dev), errp);
59     if (*errp != NULL) {
60         return;
61     }
62 
63     acpi_send_gpe_event(ar, irq, ACPI_CPU_HOTPLUG_STATUS);
64 }
65 
66 void acpi_cpu_hotplug_init(MemoryRegion *parent, Object *owner,
67                            AcpiCpuHotplug *gpe_cpu, uint16_t base)
68 {
69     CPUState *cpu;
70 
71     CPU_FOREACH(cpu) {
72         acpi_set_cpu_present_bit(gpe_cpu, cpu, &error_abort);
73     }
74     memory_region_init_io(&gpe_cpu->io, owner, &AcpiCpuHotplug_ops,
75                           gpe_cpu, "acpi-cpu-hotplug", ACPI_GPE_PROC_LEN);
76     memory_region_add_subregion(parent, base, &gpe_cpu->io);
77 }
78