From: wanghaibin <wanghaibin.wang@huawei.com>
Date: Thu, 26 Oct 2017 17:23:03 +0200
Subject: KVM: arm/arm64: vgic-its: Fix return value for device table restore
Patch-mainline: v4.14-rc8
Git-commit: b92382620e33c9f1bcbcd7c169262b9bf0525871
References: bsc#1077761

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>
Acked-by: Alexander Graf <agraf@suse.de>
---
 virt/kvm/arm/vgic/vgic-its.c |   20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -1936,6 +1936,14 @@
 	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 @@
 	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 @@
 	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 @@
 				     vgic_its_restore_dte, NULL);
 	}
 
+	/* scan_its_table returns +1 if all entries are invalid */
 	if (ret > 0)
-		ret = -EINVAL;
+		ret = 0;
 
 	return ret;
 }