KVM: arm/arm64: vgic-its: Fix return value for device table restore

If ITT only contains invalid entries, vgic_its_restore_itt
returns 1 and this is considered as an an error in
vgic_its_restore_dte.

Also in case the device table only contains invalid entries,
the table restore fails and this is not correct.

This patch fixes those 2 issues:
- vgic_its_restore_itt now returns <= 0 values. If all
  ITEs are invalid, this is considered as successful.
- vgic_its_restore_device_tables also returns <= 0 values.

We also simplify the returned value computation in
handle_l1_dte.

Signed-off-by: wanghaibin <wanghaibin.wang@huawei.com>
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 7765288..76685f4 100644 (file)
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -1936,6 +1936,14 @@ static int vgic_its_save_itt(struct vgic_its *its, struct its_device *device)
        return 0;
 }
 
+/**
+ * vgic_its_restore_itt - restore the ITT of a device
+ *
+ * @its: its handle
+ * @dev: device handle
+ *
+ * Return 0 on success, < 0 on error
+ */
 static int vgic_its_restore_itt(struct vgic_its *its, struct its_device *dev)
 {
        const struct vgic_its_abi *abi = vgic_its_get_abi(its);
@@ -1947,6 +1955,10 @@ static int vgic_its_restore_itt(struct vgic_its *its, struct its_device *dev)
        ret = scan_its_table(its, base, max_size, ite_esz, 0,
                             vgic_its_restore_ite, dev);
 
+       /* scan_its_table returns +1 if all ITEs are invalid */
+       if (ret > 0)
+               ret = 0;
+
        return ret;
 }
 
@@ -2103,10 +2115,7 @@ static int handle_l1_dte(struct vgic_its *its, u32 id, void *addr,
        ret = scan_its_table(its, gpa, SZ_64K, dte_esz,
                             l2_start_id, vgic_its_restore_dte, NULL);
 
-       if (ret <= 0)
-               return ret;
-
-       return 1;
+       return ret;
 }
 
 /**
@@ -2136,8 +2145,9 @@ static int vgic_its_restore_device_tables(struct vgic_its *its)
                                     vgic_its_restore_dte, NULL);
        }
 
+       /* scan_its_table returns +1 if all entries are invalid */
        if (ret > 0)
-               ret = -EINVAL;
+               ret = 0;
 
        return ret;
 }