kvm: x86: Add user space part for in-kernel IOAPIC

This introduces the KVM-accelerated IOAPIC model 'kvm-ioapic' and
extends the IRQ routing setup by the 0->2 redirection when needed.

The kvm-ioapic model has a property that allows to define its GSI base
for injecting interrupts into the kernel model. This will allow to
disentangle PIC and IOAPIC pins for chipsets that support more
sophisticated IRQ routes than the PIIX3. So far the base is kept at 0,
i.e. PIC and IOAPIC share pins 0..15.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

Makefile.target

@@ -233,7 +233,7 @@ obj-i386-y += vmport.o
 obj-i386-y += pci-hotplug.o smbios.o wdt_ib700.o
 obj-i386-y += debugcon.o multiboot.o
 obj-i386-y += pc_piix.o
-obj-i386-$(CONFIG_KVM) += kvm/clock.o kvm/apic.o kvm/i8259.o
+obj-i386-$(CONFIG_KVM) += kvm/clock.o kvm/apic.o kvm/i8259.o kvm/ioapic.o
 obj-i386-$(CONFIG_SPICE) += qxl.o qxl-logger.o qxl-render.o
 
 # shared objects

hw/kvm/ioapic.c

@@ -0,0 +1,114 @@
+/*
+ * KVM in-kernel IOPIC support
+ *
+ * Copyright (c) 2011 Siemens AG
+ *
+ * Authors:
+ *  Jan Kiszka          <jan.kiszka@siemens.com>
+ *
+ * This work is licensed under the terms of the GNU GPL version 2.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "hw/pc.h"
+#include "hw/ioapic_internal.h"
+#include "hw/apic_internal.h"
+#include "kvm.h"
+
+typedef struct KVMIOAPICState KVMIOAPICState;
+
+struct KVMIOAPICState {
+    IOAPICCommonState ioapic;
+    uint32_t kvm_gsi_base;
+};
+
+static void kvm_ioapic_get(IOAPICCommonState *s)
+{
+    struct kvm_irqchip chip;
+    struct kvm_ioapic_state *kioapic;
+    int ret, i;
+
+    chip.chip_id = KVM_IRQCHIP_IOAPIC;
+    ret = kvm_vm_ioctl(kvm_state, KVM_GET_IRQCHIP, &chip);
+    if (ret < 0) {
+        fprintf(stderr, "KVM_GET_IRQCHIP failed: %s\n", strerror(ret));
+        abort();
+    }
+
+    kioapic = &chip.chip.ioapic;
+
+    s->id = kioapic->id;
+    s->ioregsel = kioapic->ioregsel;
+    s->irr = kioapic->irr;
+    for (i = 0; i < IOAPIC_NUM_PINS; i++) {
+        s->ioredtbl[i] = kioapic->redirtbl[i].bits;
+    }
+}
+
+static void kvm_ioapic_put(IOAPICCommonState *s)
+{
+    struct kvm_irqchip chip;
+    struct kvm_ioapic_state *kioapic;
+    int ret, i;
+
+    chip.chip_id = KVM_IRQCHIP_IOAPIC;
+    kioapic = &chip.chip.ioapic;
+
+    kioapic->id = s->id;
+    kioapic->ioregsel = s->ioregsel;
+    kioapic->base_address = s->busdev.mmio[0].addr;
+    kioapic->irr = s->irr;
+    for (i = 0; i < IOAPIC_NUM_PINS; i++) {
+        kioapic->redirtbl[i].bits = s->ioredtbl[i];
+    }
+
+    ret = kvm_vm_ioctl(kvm_state, KVM_SET_IRQCHIP, &chip);
+    if (ret < 0) {
+        fprintf(stderr, "KVM_GET_IRQCHIP failed: %s\n", strerror(ret));
+        abort();
+    }
+}
+
+static void kvm_ioapic_reset(DeviceState *dev)
+{
+    IOAPICCommonState *s = DO_UPCAST(IOAPICCommonState, busdev.qdev, dev);
+
+    ioapic_reset_common(dev);
+    kvm_ioapic_put(s);
+}
+
+static void kvm_ioapic_set_irq(void *opaque, int irq, int level)
+{
+    KVMIOAPICState *s = opaque;
+    int delivered;
+
+    delivered = kvm_irqchip_set_irq(kvm_state, s->kvm_gsi_base + irq, level);
+    apic_report_irq_delivered(delivered);
+}
+
+static void kvm_ioapic_init(IOAPICCommonState *s, int instance_no)
+{
+    memory_region_init_reservation(&s->io_memory, "kvm-ioapic", 0x1000);
+
+    qdev_init_gpio_in(&s->busdev.qdev, kvm_ioapic_set_irq, IOAPIC_NUM_PINS);
+}
+
+static IOAPICCommonInfo kvm_ioapic_info = {
+    .busdev.qdev.name  = "kvm-ioapic",
+    .busdev.qdev.size = sizeof(KVMIOAPICState),
+    .busdev.qdev.reset = kvm_ioapic_reset,
+    .busdev.qdev.props = (Property[]) {
+        DEFINE_PROP_UINT32("gsi_base", KVMIOAPICState, kvm_gsi_base, 0),
+        DEFINE_PROP_END_OF_LIST()
+    },
+    .init      = kvm_ioapic_init,
+    .pre_save  = kvm_ioapic_get,
+    .post_load = kvm_ioapic_put,
+};
+
+static void kvm_ioapic_register_device(void)
+{
+    ioapic_qdev_register(&kvm_ioapic_info);
+}
+
+device_init(kvm_ioapic_register_device)

hw/pc_piix.c

@@ -69,6 +69,15 @@ static void kvm_piix3_setup_irq_routing(bool pci_enabled)
         for (i = 8; i < 16; ++i) {
             kvm_irqchip_add_route(s, i, KVM_IRQCHIP_PIC_SLAVE, i - 8);
         }
+        if (pci_enabled) {
+            for (i = 0; i < 24; ++i) {
+                if (i == 0) {
+                    kvm_irqchip_add_route(s, i, KVM_IRQCHIP_IOAPIC, 2);
+                } else if (i != 2) {
+                    kvm_irqchip_add_route(s, i, KVM_IRQCHIP_IOAPIC, i);
+                }
+            }
+        }
         ret = kvm_irqchip_commit_routes(s);
         if (ret < 0) {
             hw_error("KVM IRQ routing setup failed");
@@ -95,7 +104,11 @@ static void ioapic_init(GSIState *gsi_state)
     SysBusDevice *d;
     unsigned int i;
 
+    if (kvm_enabled() && kvm_irqchip_in_kernel()) {
+        dev = qdev_create(NULL, "kvm-ioapic");
+    } else {
         dev = qdev_create(NULL, "ioapic");
+    }
     qdev_init_nofail(dev);
     d = sysbus_from_qdev(dev);
     sysbus_mmio_map(d, 0, 0xfec00000);