[Qemu-devel] [RFC 4/5] hw/kvm/arm_gic: Implement support for KVM in-kernel ARM GIC

[Peter Maydell <peter.maydell@linaro.org>]

Implement support for using the KVM in-kernel GIC for ARM.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 hw/a15mpcore.c       |   11 +++-
 hw/arm/Makefile.objs |    1 +
 hw/kvm/arm_gic.c     |  153 ++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 164 insertions(+), 1 deletion(-)
 create mode 100644 hw/kvm/arm_gic.c

diff --git a/hw/a15mpcore.c b/hw/a15mpcore.c
index fc0a02a..e075849 100644
--- a/hw/a15mpcore.c
+++ b/hw/a15mpcore.c
@@ -19,6 +19,7 @@
  */
 
 #include "sysbus.h"
+#include "kvm.h"
 
 /* A15MP private memory region.  */
 
@@ -41,7 +42,15 @@ static int a15mp_priv_init(SysBusDevice *dev)
     A15MPPrivState *s = FROM_SYSBUS(A15MPPrivState, dev);
     SysBusDevice *busdev;
 
-    s->gic = qdev_create(NULL, "arm_gic");
+    /* TODO when the VGIC patches make it to Christoffer's kernel
+     * tree we can make !kvm_irqchip_in_kernel() a fatal error.
+     */
+    if (kvm_irqchip_in_kernel()) {
+        s->gic = qdev_create(NULL, "kvm-arm_gic");
+    } else {
+        s->gic = qdev_create(NULL, "arm_gic");
+    }
+
     qdev_prop_set_uint32(s->gic, "num-cpu", s->num_cpu);
     qdev_prop_set_uint32(s->gic, "num-irq", s->num_irq);
     qdev_prop_set_uint32(s->gic, "revision", 2);
diff --git a/hw/arm/Makefile.objs b/hw/arm/Makefile.objs
index c413780..881fffd 100644
--- a/hw/arm/Makefile.objs
+++ b/hw/arm/Makefile.objs
@@ -39,5 +39,6 @@ obj-y += imx_serial.o imx_ccm.o imx_timer.o imx_avic.o
 obj-y += kzm.o
 obj-y += pl041.o lm4549.o
 obj-$(CONFIG_FDT) += ../device_tree.o
+obj-$(CONFIG_KVM) += kvm/arm_gic.o
 
 obj-y := $(addprefix ../,$(obj-y))
diff --git a/hw/kvm/arm_gic.c b/hw/kvm/arm_gic.c
new file mode 100644
index 0000000..4535f90
--- /dev/null
+++ b/hw/kvm/arm_gic.c
@@ -0,0 +1,153 @@
+/*
+ * ARM Generic Interrupt Controller using KVM in-kernel support
+ *
+ * Copyright (c) 2012 Linaro Limited
+ * Written by Peter Maydell
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "hw/sysbus.h"
+#include "kvm.h"
+#include "hw/arm_gic_internal.h"
+
+#define TYPE_KVM_ARM_GIC "kvm-arm_gic"
+#define KVM_ARM_GIC(obj) \
+     OBJECT_CHECK(gic_state, (obj), TYPE_KVM_ARM_GIC)
+#define KVM_ARM_GIC_CLASS(klass) \
+     OBJECT_CLASS_CHECK(KVMARMGICClass, (klass), TYPE_KVM_ARM_GIC)
+#define KVM_ARM_GIC_GET_CLASS(obj) \
+     OBJECT_GET_CLASS(KVMARMGICClass, (obj), TYPE_KVM_ARM_GIC)
+
+typedef struct KVMARMGICClass {
+    ARMGICCommonClass parent_class;
+    int (*parent_init)(SysBusDevice *dev);
+    void (*parent_reset)(DeviceState *dev);
+} KVMARMGICClass;
+
+static void kvm_arm_gic_set_irq(void *opaque, int irq, int level)
+{
+    /* Meaning of the 'irq' parameter:
+     *  [0..N-1] : external interrupts
+     *  [N..N+31] : PPI (internal) interrupts for CPU 0
+     *  [N+32..N+63] : PPI (internal interrupts for CPU 1
+     *  ...
+     */
+    gic_state *s = (gic_state *)opaque;
+
+
+    if (irq < (s->num_irq - GIC_INTERNAL)) {
+        /* External interrupt number 'irq' */
+        kvm_set_irq(kvm_state, irq + GIC_INTERNAL, !!level);
+    } else {
+        struct kvm_irq_level irq_level;
+        int cpu;
+        irq -= (s->num_irq - GIC_INTERNAL);
+        cpu = irq / GIC_INTERNAL;
+        irq %= GIC_INTERNAL;
+        /* Internal interrupt 'irq' for CPU 'cpu' */
+        irq_level.irq = irq;
+        irq_level.level = !!level;
+        kvm_vcpu_ioctl(qemu_get_cpu(cpu), KVM_IRQ_LINE, &irq_level);
+    }
+}
+
+static void kvm_arm_gic_put(gic_state *s)
+{
+    /* TODO: there isn't currently a kernel interface to set the GIC state */
+}
+
+static void kvm_arm_gic_get(gic_state *s)
+{
+    /* TODO: there isn't currently a kernel interface to get the GIC state */
+}
+
+static void kvm_arm_gic_reset(DeviceState *dev)
+{
+    gic_state *s = ARM_GIC_COMMON(dev);
+    KVMARMGICClass *kgc = KVM_ARM_GIC_GET_CLASS(s);
+    kgc->parent_reset(dev);
+    kvm_arm_gic_put(s);
+}
+
+static int kvm_arm_gic_init(SysBusDevice *dev)
+{
+    /* Device instance init function for the GIC sysbus device */
+    int i;
+    gic_state *s = FROM_SYSBUS(gic_state, dev);
+    KVMARMGICClass *kgc = KVM_ARM_GIC_GET_CLASS(s);
+
+    kgc->parent_init(dev);
+
+    i = s->num_irq - GIC_INTERNAL;
+    /* For the GIC, also expose incoming GPIO lines for PPIs for each CPU.
+     * GPIO array layout is thus:
+     *  [0..N-1] SPIs
+     *  [N..N+31] PPIs for CPU 0
+     *  [N+32..N+63] PPIs for CPU 1
+     *   ...
+     */
+    i += (GIC_INTERNAL * s->num_cpu);
+    qdev_init_gpio_in(&s->busdev.qdev, kvm_arm_gic_set_irq, i);
+    /* We never use our outbound IRQ lines but provide them so that
+     * we maintain the same interface as the non-KVM GIC.
+     */
+    for (i = 0; i < s->num_cpu; i++) {
+        sysbus_init_irq(&s->busdev, &s->parent_irq[i]);
+    }
+    /* Distributor */
+    memory_region_init_reservation(&s->iomem, "kvm-gic_dist", 0x1000);
+    sysbus_init_mmio(dev, &s->iomem);
+    /* CPU interface for current core. Unlike arm_gic, we don't
+     * provide the "interface for core #N" memory regions, because
+     * cores with a VGIC don't have those.
+     */
+    memory_region_init_reservation(&s->cpuiomem[0], "kvm-gic_cpu", 0x1000);
+    sysbus_init_mmio(dev, &s->cpuiomem[0]);
+    /* TODO: we should tell the kernel at some point the address
+     * of the private peripheral base. However we don't currently have
+     * any convenient infrastructure to do that, and in any case the
+     * kernel doesn't yet implement an ioctl to let us tell it.
+     */
+    return 0;
+}
+
+static void kvm_arm_gic_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    SysBusDeviceClass *sbc = SYS_BUS_DEVICE_CLASS(klass);
+    ARMGICCommonClass *agcc = ARM_GIC_COMMON_CLASS(klass);
+    KVMARMGICClass *kgc = KVM_ARM_GIC_CLASS(klass);
+    agcc->pre_save = kvm_arm_gic_get;
+    agcc->post_load = kvm_arm_gic_put;
+    kgc->parent_init = sbc->init;
+    kgc->parent_reset = dc->reset;
+    sbc->init = kvm_arm_gic_init;
+    dc->reset = kvm_arm_gic_reset;
+    dc->no_user = 1;
+}
+
+static TypeInfo arm_gic_info = {
+    .name = TYPE_KVM_ARM_GIC,
+    .parent = TYPE_ARM_GIC_COMMON,
+    .instance_size = sizeof(gic_state),
+    .class_init = kvm_arm_gic_class_init,
+};
+
+static void arm_gic_register_types(void)
+{
+    type_register_static(&arm_gic_info);
+}
+
+type_init(arm_gic_register_types)
-- 
1.7.9.5