[Qemu-arm] [RFC v3 2/4] hw/intc/arm_gicv3_its: Implement a minimalist reset

[Eric Auger <eric.auger@redhat.com>]

At the moment the ITS is not properly reset and this causes
various bugs on save/restore. We implement a minimalist reset
through individual register writes but for kernel versions
before v4.15 this fails voiding the vITS cache. We cannot
claim we have a comprehensive reset (hence the error message)
but that's better than nothing.

Signed-off-by: Eric Auger <eric.auger@redhat.com>

---

v2 -> v3:
- individual register writes performed in kvm_arm_its_reset
- check KVM_DEV_ARM_VGIC_GRP_ITS_REGS support
---
 hw/intc/arm_gicv3_its_kvm.c | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/hw/intc/arm_gicv3_its_kvm.c b/hw/intc/arm_gicv3_its_kvm.c
index b1b322b..83e5268 100644
--- a/hw/intc/arm_gicv3_its_kvm.c
+++ b/hw/intc/arm_gicv3_its_kvm.c
@@ -28,6 +28,16 @@
 
 #define TYPE_KVM_ARM_ITS "arm-its-kvm"
 #define KVM_ARM_ITS(obj) OBJECT_CHECK(GICv3ITSState, (obj), TYPE_KVM_ARM_ITS)
+#define KVM_ARM_ITS_CLASS(klass) \
+     OBJECT_CLASS_CHECK(KVMARMITSClass, (klass), TYPE_KVM_ARM_ITS)
+#define KVM_ARM_ITS_GET_CLASS(obj) \
+     OBJECT_GET_CLASS(KVMARMITSClass, (obj), TYPE_KVM_ARM_ITS)
+
+typedef struct KVMARMITSClass {
+    GICv3ITSCommonClass parent_class;
+    void (*parent_reset)(DeviceState *dev);
+} KVMARMITSClass;
+
 
 static int kvm_its_send_msi(GICv3ITSState *s, uint32_t value, uint16_t devid)
 {
@@ -186,6 +196,34 @@ static void kvm_arm_its_post_load(GICv3ITSState *s)
                       GITS_CTLR, &s->ctlr, true, &error_abort);
 }
 
+static void kvm_arm_its_reset(DeviceState *dev)
+{
+    GICv3ITSState *s = ARM_GICV3_ITS_COMMON(dev);
+    KVMARMITSClass *c = KVM_ARM_ITS_GET_CLASS(s);
+    int i;
+
+    c->parent_reset(dev);
+
+    error_report("ITS KVM: full reset is not supported by the host kernel");
+
+    if (!kvm_device_check_attr(s->dev_fd, KVM_DEV_ARM_VGIC_GRP_ITS_REGS,
+                               GITS_CTLR)) {
+        return;
+    }
+
+    kvm_device_access(s->dev_fd, KVM_DEV_ARM_VGIC_GRP_ITS_REGS,
+                      GITS_CTLR, &s->ctlr, true, &error_abort);
+
+    kvm_device_access(s->dev_fd, KVM_DEV_ARM_VGIC_GRP_ITS_REGS,
+                      GITS_CBASER, &s->cbaser, true, &error_abort);
+
+    for (i = 0; i < 8; i++) {
+        kvm_device_access(s->dev_fd, KVM_DEV_ARM_VGIC_GRP_ITS_REGS,
+                          GITS_BASER + i * 8, &s->baser[i], true,
+                          &error_abort);
+    }
+}
+
 static Property kvm_arm_its_props[] = {
     DEFINE_PROP_LINK("parent-gicv3", GICv3ITSState, gicv3, "kvm-arm-gicv3",
                      GICv3State *),
@@ -196,12 +234,15 @@ static void kvm_arm_its_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
     GICv3ITSCommonClass *icc = ARM_GICV3_ITS_COMMON_CLASS(klass);
+    KVMARMITSClass *ic = KVM_ARM_ITS_CLASS(klass);
 
     dc->realize = kvm_arm_its_realize;
     dc->props   = kvm_arm_its_props;
+    ic->parent_reset = dc->reset;
     icc->send_msi = kvm_its_send_msi;
     icc->pre_save = kvm_arm_its_pre_save;
     icc->post_load = kvm_arm_its_post_load;
+    dc->reset = kvm_arm_its_reset;
 }
 
 static const TypeInfo kvm_arm_its_info = {
-- 
2.5.5