diff options
-rw-r--r-- | docs/specs/acpi_cpu_hotplug.txt | 22 | ||||
-rw-r--r-- | hw/acpi/piix4.c | 90 |
2 files changed, 110 insertions, 2 deletions
diff --git a/docs/specs/acpi_cpu_hotplug.txt b/docs/specs/acpi_cpu_hotplug.txt new file mode 100644 index 0000000..5dec0c5 --- /dev/null +++ b/docs/specs/acpi_cpu_hotplug.txt @@ -0,0 +1,22 @@ +QEMU<->ACPI BIOS CPU hotplug interface +-------------------------------------- + +QEMU supports CPU hotplug via ACPI. This document +describes the interface between QEMU and the ACPI BIOS. + +ACPI GPE block (IO ports 0xafe0-0xafe3, byte access): +----------------------------------------- + +Generic ACPI GPE block. Bit 2 (GPE.2) used to notify CPU +hot-add/remove event to ACPI BIOS, via SCI interrupt. + +CPU present bitmap (IO port 0xaf00-0xae1f, 1-byte access): +--------------------------------------------------------------- +One bit per CPU. Bit position reflects corresponding CPU APIC ID. +Read-only. + +CPU hot-add/remove notification: +----------------------------------------------------- +QEMU sets/clears corresponding CPU bit on hot-add/remove event. +CPU present map read by ACPI BIOS GPE.2 handler to notify OS of CPU +hot-(un)plug events. diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c index 88386d7..c4af1cc 100644 --- a/hw/acpi/piix4.c +++ b/hw/acpi/piix4.c @@ -48,19 +48,28 @@ #define PCI_EJ_BASE 0xae08 #define PCI_RMV_BASE 0xae0c +#define PIIX4_PROC_BASE 0xaf00 +#define PIIX4_PROC_LEN 32 + #define PIIX4_PCI_HOTPLUG_STATUS 2 +#define PIIX4_CPU_HOTPLUG_STATUS 4 struct pci_status { uint32_t up; /* deprecated, maintained for migration compatibility */ uint32_t down; }; +typedef struct CPUStatus { + uint8_t sts[PIIX4_PROC_LEN]; +} CPUStatus; + typedef struct PIIX4PMState { PCIDevice dev; MemoryRegion io; MemoryRegion io_gpe; MemoryRegion io_pci; + MemoryRegion io_cpu; ACPIREGS ar; APMState apm; @@ -82,6 +91,9 @@ typedef struct PIIX4PMState { uint8_t disable_s3; uint8_t disable_s4; uint8_t s4_val; + + CPUStatus gpe_cpu; + Notifier cpu_added_notifier; } PIIX4PMState; static void piix4_acpi_system_hot_add_init(MemoryRegion *parent, @@ -100,8 +112,8 @@ static void pm_update_sci(PIIX4PMState *s) ACPI_BITMASK_POWER_BUTTON_ENABLE | ACPI_BITMASK_GLOBAL_LOCK_ENABLE | ACPI_BITMASK_TIMER_ENABLE)) != 0) || - (((s->ar.gpe.sts[0] & s->ar.gpe.en[0]) - & PIIX4_PCI_HOTPLUG_STATUS) != 0); + (((s->ar.gpe.sts[0] & s->ar.gpe.en[0]) & + (PIIX4_PCI_HOTPLUG_STATUS | PIIX4_CPU_HOTPLUG_STATUS)) != 0); qemu_set_irq(s->irq, sci_level); /* schedule a timer interruption if needed */ @@ -585,6 +597,73 @@ static const MemoryRegionOps piix4_pci_ops = { }, }; +static uint64_t cpu_status_read(void *opaque, hwaddr addr, unsigned int size) +{ + PIIX4PMState *s = opaque; + CPUStatus *cpus = &s->gpe_cpu; + uint64_t val = cpus->sts[addr]; + + return val; +} + +static void cpu_status_write(void *opaque, hwaddr addr, uint64_t data, + unsigned int size) +{ + /* TODO: implement VCPU removal on guest signal that CPU can be removed */ +} + +static const MemoryRegionOps cpu_hotplug_ops = { + .read = cpu_status_read, + .write = cpu_status_write, + .endianness = DEVICE_LITTLE_ENDIAN, + .valid = { + .min_access_size = 1, + .max_access_size = 1, + }, +}; + +typedef enum { + PLUG, + UNPLUG, +} HotplugEventType; + +static void piix4_cpu_hotplug_req(PIIX4PMState *s, CPUState *cpu, + HotplugEventType action) +{ + CPUStatus *g = &s->gpe_cpu; + ACPIGPE *gpe = &s->ar.gpe; + CPUClass *k = CPU_GET_CLASS(cpu); + int64_t cpu_id; + + assert(s != NULL); + + *gpe->sts = *gpe->sts | PIIX4_CPU_HOTPLUG_STATUS; + cpu_id = k->get_arch_id(CPU(cpu)); + if (action == PLUG) { + g->sts[cpu_id / 8] |= (1 << (cpu_id % 8)); + } else { + g->sts[cpu_id / 8] &= ~(1 << (cpu_id % 8)); + } + pm_update_sci(s); +} + +static void piix4_cpu_added_req(Notifier *n, void *opaque) +{ + PIIX4PMState *s = container_of(n, PIIX4PMState, cpu_added_notifier); + + piix4_cpu_hotplug_req(s, CPU(opaque), PLUG); +} + +static void piix4_init_cpu_status(CPUState *cpu, void *data) +{ + CPUStatus *g = (CPUStatus *)data; + CPUClass *k = CPU_GET_CLASS(cpu); + int64_t id = k->get_arch_id(cpu); + + g_assert((id / 8) < PIIX4_PROC_LEN); + g->sts[id / 8] |= (1 << (id % 8)); +} + static int piix4_device_hotplug(DeviceState *qdev, PCIDevice *dev, PCIHotplugState state); @@ -600,6 +679,13 @@ static void piix4_acpi_system_hot_add_init(MemoryRegion *parent, memory_region_add_subregion(parent, PCI_HOTPLUG_ADDR, &s->io_pci); pci_bus_hotplug(bus, piix4_device_hotplug, &s->dev.qdev); + + qemu_for_each_cpu(piix4_init_cpu_status, &s->gpe_cpu); + memory_region_init_io(&s->io_cpu, &cpu_hotplug_ops, s, "apci-cpu-hotplug", + PIIX4_PROC_LEN); + memory_region_add_subregion(parent, PIIX4_PROC_BASE, &s->io_cpu); + s->cpu_added_notifier.notify = piix4_cpu_added_req; + qemu_register_cpu_added_notifier(&s->cpu_added_notifier); } static void enable_device(PIIX4PMState *s, int slot) |