From 8c58be34494b7f1b2adb446e2d8beeb90e5de65b Mon Sep 17 00:00:00 2001
From: Eric Auger <eric.auger@redhat.com>
Date: Fri, 13 Dec 2019 10:42:37 +0100
Subject: [PATCH] KVM: arm/arm64: vgic-its: Fix restoration of unmapped
 collections

Saving/restoring an unmapped collection is a valid scenario. For
example this happens if a MAPTI command was sent, featuring an
unmapped collection. At the moment the CTE fails to be restored.
Only compare against the number of online vcpus if the rdist
base is set.

Fixes: ea1ad53e1e31a ("KVM: arm64: vgic-its: Collection table save/restore")
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Link: https://lore.kernel.org/r/20191213094237.19627-1-eric.auger@redhat.com
---
 virt/kvm/arm/vgic/vgic-its.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 98c7360d9fb70..17920d1b350a2 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -2475,7 +2475,8 @@ static int vgic_its_restore_cte(struct vgic_its *its, gpa_t gpa, int esz)
 	target_addr = (u32)(val >> KVM_ITS_CTE_RDBASE_SHIFT);
 	coll_id = val & KVM_ITS_CTE_ICID_MASK;
 
-	if (target_addr >= atomic_read(&kvm->online_vcpus))
+	if (target_addr != COLLECTION_NOT_MAPPED &&
+	    target_addr >= atomic_read(&kvm->online_vcpus))
 		return -EINVAL;
 
 	collection = find_collection(its, coll_id);
-- 
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