[Qemu-devel] [PATCH 6/7] Prepare ACPI infrastructure for cpu hot-plug in acpi_piix4

[Igor Mammedov <imammedo@redhat.com>]

It's backport of acpi related cpu-hotplug code from qemu-kvm.
Provides means to communicate cpu hot-plug events to guest OS
and that works with current seabios.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
---
 hw/acpi_piix4.c |   65 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
 hw/pc.h         |    1 +
 2 files changed, 64 insertions(+), 2 deletions(-)

diff --git a/hw/acpi_piix4.c b/hw/acpi_piix4.c
index bdc55a1..5a83d73 100644
--- a/hw/acpi_piix4.c
+++ b/hw/acpi_piix4.c
@@ -43,9 +43,15 @@
 #define PCI_BASE 0xae00
 #define PCI_EJ_BASE 0xae08
 #define PCI_RMV_BASE 0xae0c
+#define PROC_BASE 0xaf00
 
+#define PIIX4_CPU_HOTPLUG_STATUS 4
 #define PIIX4_PCI_HOTPLUG_STATUS 2
 
+struct gpe_regs {
+    uint8_t cpus_sts[32];
+};
+
 struct pci_status {
     uint32_t up;
     uint32_t down;
@@ -71,6 +77,7 @@ typedef struct PIIX4PMState {
 
     /* for pci hotplug */
     ACPIGPE gpe;
+    struct gpe_regs gpe_cpu;
     struct pci_status pci0_status;
     uint32_t pci0_hotplug_enable;
 } PIIX4PMState;
@@ -90,7 +97,8 @@ static void pm_update_sci(PIIX4PMState *s)
                    ACPI_BITMASK_POWER_BUTTON_ENABLE |
                    ACPI_BITMASK_GLOBAL_LOCK_ENABLE |
                    ACPI_BITMASK_TIMER_ENABLE)) != 0) ||
-        (((s->gpe.sts[0] & s->gpe.en[0]) & PIIX4_PCI_HOTPLUG_STATUS) != 0);
+        (((s->gpe.sts[0] & s->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 */
@@ -329,11 +337,16 @@ static void piix4_pm_machine_ready(Notifier *n, void *opaque)
 
 }
 
+static PIIX4PMState *global_piix4_pm_state; /* cpu hotadd */
+
 static int piix4_pm_initfn(PCIDevice *dev)
 {
     PIIX4PMState *s = DO_UPCAST(PIIX4PMState, dev, dev);
     uint8_t *pci_conf;
 
+    /* for cpu hotadd */
+    global_piix4_pm_state = s;
+
     pci_conf = s->dev.config;
     pci_conf[0x06] = 0x80;
     pci_conf[0x07] = 0x02;
@@ -425,8 +438,17 @@ device_init(piix4_pm_register);
 static uint32_t gpe_readb(void *opaque, uint32_t addr)
 {
     PIIX4PMState *s = opaque;
-    uint32_t val = acpi_gpe_ioport_readb(&s->gpe, addr);
+    uint32_t val = 0;
+    struct gpe_regs *g = &s->gpe_cpu;
 
+    switch (addr) {
+    case PROC_BASE ... PROC_BASE+31:
+        val = g->cpus_sts[addr - PROC_BASE];
+        break;
+    default:
+        val = acpi_gpe_ioport_readb(&s->gpe, addr);
+    }
+ 
     PIIX4_DPRINTF("gpe read %x == %x\n", addr, val);
     return val;
 }
@@ -519,11 +541,20 @@ static int piix4_device_hotplug(DeviceState *qdev, PCIDevice *dev,
 static void piix4_acpi_system_hot_add_init(PCIBus *bus, PIIX4PMState *s)
 {
     struct pci_status *pci0_status = &s->pci0_status;
+    int i = 0, cpus = smp_cpus;
 
+    while (cpus > 0) {
+        s->gpe_cpu.cpus_sts[i++] = (cpus < 8) ? (1 << cpus) - 1 : 0xff;
+        cpus -= 8;
+    }
+ 
     register_ioport_write(GPE_BASE, GPE_LEN, 1, gpe_writeb, s);
     register_ioport_read(GPE_BASE, GPE_LEN, 1,  gpe_readb, s);
     acpi_gpe_blk(&s->gpe, GPE_BASE);
 
+    register_ioport_write(PROC_BASE, 32, 1, gpe_writeb, s);
+    register_ioport_read(PROC_BASE, 32, 1,  gpe_readb, s);
+
     register_ioport_write(PCI_BASE, 8, 4, pcihotplug_write, pci0_status);
     register_ioport_read(PCI_BASE, 8, 4,  pcihotplug_read, pci0_status);
 
@@ -536,6 +567,36 @@ static void piix4_acpi_system_hot_add_init(PCIBus *bus, PIIX4PMState *s)
     pci_bus_hotplug(bus, piix4_device_hotplug, &s->dev.qdev);
 }
 
+static void enable_processor(PIIX4PMState *s, int cpu)
+{
+    struct gpe_regs *g = &s->gpe_cpu;
+    ACPIGPE *gpe = &s->gpe;
+
+    *gpe->sts = *gpe->sts | PIIX4_CPU_HOTPLUG_STATUS;
+    g->cpus_sts[cpu / 8] |= (1 << (cpu % 8));
+}
+
+static void disable_processor(PIIX4PMState *s, int cpu)
+{
+    struct gpe_regs *g = &s->gpe_cpu;
+    ACPIGPE *gpe = &s->gpe;
+
+    *gpe->sts = *gpe->sts | PIIX4_CPU_HOTPLUG_STATUS;
+    g->cpus_sts[cpu / 8] &= ~(1 << (cpu % 8));
+}
+
+void acpi_cpu_hot_plug(int cpu, int state)
+{
+    PIIX4PMState *s = global_piix4_pm_state;
+
+    if (state) {
+        enable_processor(s, cpu);
+    } else {
+        disable_processor(s, cpu);
+    }
+    pm_update_sci(s);
+}
+
 static void enable_device(PIIX4PMState *s, int slot)
 {
     s->gpe.sts[0] |= PIIX4_PCI_HOTPLUG_STATUS;
diff --git a/hw/pc.h b/hw/pc.h
index 13e41f1..fd1e09c 100644
--- a/hw/pc.h
+++ b/hw/pc.h
@@ -163,6 +163,7 @@ extern size_t acpi_tables_len;
 
 void acpi_bios_init(void);
 int acpi_table_add(const char *table_desc);
+void acpi_cpu_hot_plug(int cpu, int state);
 
 /* acpi_piix.c */
 
-- 
1.7.7.6