xref: /openbmc/qemu/hw/acpi/cpu_hotplug.c (revision 228aa992)
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 "hw/hw.h"
13 #include "hw/acpi/cpu_hotplug.h"
14 
15 static uint64_t cpu_status_read(void *opaque, hwaddr addr, unsigned int size)
16 {
17     AcpiCpuHotplug *cpus = opaque;
18     uint64_t val = cpus->sts[addr];
19 
20     return val;
21 }
22 
23 static void cpu_status_write(void *opaque, hwaddr addr, uint64_t data,
24                              unsigned int size)
25 {
26     /* TODO: implement VCPU removal on guest signal that CPU can be removed */
27 }
28 
29 static const MemoryRegionOps AcpiCpuHotplug_ops = {
30     .read = cpu_status_read,
31     .write = cpu_status_write,
32     .endianness = DEVICE_LITTLE_ENDIAN,
33     .valid = {
34         .min_access_size = 1,
35         .max_access_size = 1,
36     },
37 };
38 
39 static void acpi_set_cpu_present_bit(AcpiCpuHotplug *g, CPUState *cpu,
40                                      Error **errp)
41 {
42     CPUClass *k = CPU_GET_CLASS(cpu);
43     int64_t cpu_id;
44 
45     cpu_id = k->get_arch_id(cpu);
46     if ((cpu_id / 8) >= ACPI_GPE_PROC_LEN) {
47         error_setg(errp, "acpi: invalid cpu id: %" PRIi64, cpu_id);
48         return;
49     }
50 
51     g->sts[cpu_id / 8] |= (1 << (cpu_id % 8));
52 }
53 
54 void acpi_cpu_plug_cb(ACPIREGS *ar, qemu_irq irq,
55                       AcpiCpuHotplug *g, DeviceState *dev, Error **errp)
56 {
57     acpi_set_cpu_present_bit(g, CPU(dev), errp);
58     if (*errp != NULL) {
59         return;
60     }
61 
62     ar->gpe.sts[0] |= ACPI_CPU_HOTPLUG_STATUS;
63     acpi_update_sci(ar, irq);
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