[Qemu-devel] [PATCH v4 14/15] kvm: x86: Add user space part for in-kernel IOAPIC

[Jan Kiszka]

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

The IOAPIC gains a KVM-specific property that allows to define the 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 <address@hidden>
---
 Makefile.target      |    2 +-
 hw/ioapic_common.c   |    1 +
 hw/ioapic_internal.h |    1 +
 hw/kvm/ioapic.c      |  101 ++++++++++++++++++++++++++++++++++++++++++++++++++
 hw/pc_piix.c         |   15 +++++++-
 5 files changed, 118 insertions(+), 2 deletions(-)
 create mode 100644 hw/kvm/ioapic.c

diff --git a/Makefile.target b/Makefile.target
index fb10143..b48bb57 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -236,7 +236,7 @@ obj-i386-y += vmport.o
 obj-i386-y += device-hotplug.o 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
diff --git a/hw/ioapic_common.c b/hw/ioapic_common.c
index 094551c..efc1d44 100644
--- a/hw/ioapic_common.c
+++ b/hw/ioapic_common.c
@@ -122,6 +122,7 @@ static SysBusDeviceInfo ioapic_info = {
     .qdev.no_user = 1,
     .qdev.props = (Property[]) {
         DEFINE_PROP_STRING("backend", IOAPICState, backend_name),
+        DEFINE_PROP_UINT32("kvm_gsi_base", IOAPICState, kvm_gsi_base, 0),
         DEFINE_PROP_END_OF_LIST(),
     },
 };
diff --git a/hw/ioapic_internal.h b/hw/ioapic_internal.h
index c5fab8b..bf63115 100644
--- a/hw/ioapic_internal.h
+++ b/hw/ioapic_internal.h
@@ -95,6 +95,7 @@ struct IOAPICState {
 
     char *backend_name;
     IOAPICBackend *backend;
+    uint32_t kvm_gsi_base;
 };
 
 void ioapic_register_device(void);
diff --git a/hw/kvm/ioapic.c b/hw/kvm/ioapic.c
new file mode 100644
index 0000000..0e66240
--- /dev/null
+++ b/hw/kvm/ioapic.c
@@ -0,0 +1,101 @@
+/*
+ * KVM in-kernel IOPIC support
+ *
+ * Copyright (c) 2011 Siemens AG
+ *
+ * Authors:
+ *  Jan Kiszka          <address@hidden>
+ *
+ * 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"
+
+static void kvm_ioapic_get(IOAPICState *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(IOAPICState *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(IOAPICState *s)
+{
+    ioapic_reset_internal(s);
+
+    kvm_ioapic_put(s);
+}
+
+static void kvm_ioapic_set_irq(void *opaque, int irq, int level)
+{
+    IOAPICState *s = opaque;
+    int delivered;
+
+    delivered = kvm_irqchip_set_irq(kvm_state, s->kvm_gsi_base + irq, level);
+    apic_set_irq_delivered(delivered);
+}
+
+static void kvm_ioapic_backend_init(IOAPICState *s, int index)
+{
+    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 IOAPICBackend kvm_ioapic_backend = {
+    .name = "KVM",
+    .init = kvm_ioapic_backend_init,
+    .reset = kvm_ioapic_reset,
+    .pre_save = kvm_ioapic_get,
+    .post_load = kvm_ioapic_put,
+};
+
+static void kvm_ioapic_register(void)
+{
+    ioapic_register_backend(&kvm_ioapic_backend);
+}
+
+device_init(kvm_ioapic_register)
diff --git a/hw/pc_piix.c b/hw/pc_piix.c
index 8650319..93d0eba 100644
--- a/hw/pc_piix.c
+++ b/hw/pc_piix.c
@@ -68,6 +68,15 @@ 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");
@@ -89,12 +98,16 @@ static void kvm_piix3_gsi_handler(void *opaque, int n, int 
level)
 
 static void ioapic_init(GSIState *gsi_state)
 {
+    const char *backend = "QEMU";
     DeviceState *dev;
     SysBusDevice *d;
     unsigned int i;
 
     dev = qdev_create(NULL, "ioapic");
-    qdev_prop_set_string(dev, "backend", g_strdup("QEMU"));
+    if (kvm_enabled() && kvm_irqchip_in_kernel()) {
+        backend = "KVM";
+    }
+    qdev_prop_set_string(dev, "backend", g_strdup(backend));
     qdev_init_nofail(dev);
     d = sysbus_from_qdev(dev);
     sysbus_mmio_map(d, 0, 0xfec00000);
-- 
1.7.3.4