[Qemu-devel] [PATCH 2/2] hw/intc/arm_gic: Initialize the vgic on machine init done

[Eric Auger <eric.auger@linaro.org>]

With current implementation the vgic is instantiated very late,
when the VM is started, on the first VCPU run execution. This patch
forces its initialization in a machine init done notifier. This
latter is registered in the vgic realize function. The notifier uses
a new group/attribute that allows such operation. In practice, vgic
initialization can be done as soon as those dimensioning parameters
are known:
- the number of IRQs,
- the number of vcpus
- start address of dist and CPU interface (set in a memory listener).

This earlier initialization allows, for example, to setup VFIO
signaling after vgic initialization, on a reset notifier.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
---
 hw/intc/arm_gic_kvm.c            | 21 +++++++++++++++++++++
 include/hw/intc/arm_gic_common.h |  1 +
 2 files changed, 22 insertions(+)

diff --git a/hw/intc/arm_gic_kvm.c b/hw/intc/arm_gic_kvm.c
index 5038885..24fdf98 100644
--- a/hw/intc/arm_gic_kvm.c
+++ b/hw/intc/arm_gic_kvm.c
@@ -23,6 +23,7 @@
 #include "sysemu/kvm.h"
 #include "kvm_arm.h"
 #include "gic_internal.h"
+#include "sysemu/sysemu.h"
 
 //#define DEBUG_GIC_KVM
 
@@ -511,6 +512,17 @@ static void kvm_arm_gic_reset(DeviceState *dev)
     kvm_arm_gic_put(s);
 }
 
+static void kvm_arm_vgic_init_notify(Notifier *notifier, void *data)
+{
+    GICState *s = container_of(notifier, GICState, init_notifier);
+    struct kvm_device_attr attr = {
+         .group = KVM_DEV_ARM_VGIC_GRP_CTRL,
+         .attr = KVM_DEV_ARM_VGIC_CTRL_INIT};
+    if (s->dev_fd >= 0) {
+        kvm_device_ioctl(s->dev_fd, KVM_SET_DEVICE_ATTR, &attr);
+    }
+}
+
 static void kvm_arm_gic_realize(DeviceState *dev, Error **errp)
 {
     int i;
@@ -553,6 +565,15 @@ static void kvm_arm_gic_realize(DeviceState *dev, Error **errp)
         return;
     }
 
+    /*
+     * Register a notifier that will request the VGIC initialization.
+     * It will be executed after the notifier registered by
+     * kvm_arm_register_device whose role is to set dist and cpu interface
+     * base address. Also IRQ and VCPU number is known.
+     */
+    s->init_notifier.notify = kvm_arm_vgic_init_notify;
+    qemu_add_machine_init_done_notifier(&s->init_notifier);
+
     /* Distributor */
     memory_region_init_reservation(&s->iomem, OBJECT(s),
                                    "kvm-gic_dist", 0x1000);
diff --git a/include/hw/intc/arm_gic_common.h b/include/hw/intc/arm_gic_common.h
index f6887ed..98653c9 100644
--- a/include/hw/intc/arm_gic_common.h
+++ b/include/hw/intc/arm_gic_common.h
@@ -105,6 +105,7 @@ typedef struct GICState {
     uint32_t num_irq;
     uint32_t revision;
     int dev_fd; /* kvm device fd if backed by kvm vgic support */
+    Notifier init_notifier; /* notifier used to init the vgic */
 } GICState;
 
 #define TYPE_ARM_GIC_COMMON "arm_gic_common"
-- 
1.8.3.2