[Qemu-devel] [RFC 1/3] hw/intc/arm_gicv3_its: Don't abort on table save/restore

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

The ITS is not properly reset at the moment. It is possible the
GITS_BASER<n>.valid is set and the in-kernel ITS caches are not
empty (list of devices, collections, LPIs) while data structures
in guest RAM are invalid/inconsistent.

For instance, this happens after a guest shutdown -r now or a
system reset, if we save the state before the guest re-writes
the ITS registers or map devices, the table save ioctl may
produce a QEMU abort.

Until there is a proper reset implemented, let's unplug the
consistency error checking.

The reset issue will be fixed in subsequent patches.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reported-by: wanghaibin <wanghaibin.wang@huawei.com>

---

this patch would deserve being cc'ed stable (2.10)
---
 hw/intc/arm_gicv3_its_kvm.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/hw/intc/arm_gicv3_its_kvm.c b/hw/intc/arm_gicv3_its_kvm.c
index 39903d5..120b86d 100644
--- a/hw/intc/arm_gicv3_its_kvm.c
+++ b/hw/intc/arm_gicv3_its_kvm.c
@@ -64,20 +64,16 @@ static void vm_change_state_handler(void *opaque, int running,
 {
     GICv3ITSState *s = (GICv3ITSState *)opaque;
     Error *err = NULL;
-    int ret;
 
     if (running) {
         return;
     }
 
-    ret = kvm_device_access(s->dev_fd, KVM_DEV_ARM_VGIC_GRP_CTRL,
-                            KVM_DEV_ARM_ITS_SAVE_TABLES, NULL, true, &err);
+    kvm_device_access(s->dev_fd, KVM_DEV_ARM_VGIC_GRP_CTRL,
+                      KVM_DEV_ARM_ITS_SAVE_TABLES, NULL, true, &err);
     if (err) {
         error_report_err(err);
     }
-    if (ret < 0 && ret != -EFAULT) {
-        abort();
-    }
 }
 
 static void kvm_arm_its_realize(DeviceState *dev, Error **errp)
@@ -157,6 +153,7 @@ static void kvm_arm_its_pre_save(GICv3ITSState *s)
  */
 static void kvm_arm_its_post_load(GICv3ITSState *s)
 {
+    Error *err = NULL;
     int i;
 
     if (!s->iidr) {
@@ -188,7 +185,11 @@ static void kvm_arm_its_post_load(GICv3ITSState *s)
 
     kvm_device_access(s->dev_fd, KVM_DEV_ARM_VGIC_GRP_CTRL,
                       KVM_DEV_ARM_ITS_RESTORE_TABLES, NULL, true,
-                      &error_abort);
+                      &err);
+
+    if (err) {
+        error_report_err(err);
+    }
 
     kvm_device_access(s->dev_fd, KVM_DEV_ARM_VGIC_GRP_ITS_REGS,
                       GITS_CTLR, &s->ctlr, true, &error_abort);
-- 
2.5.5