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

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 98c7360..17920d1 100644 (file)
--- 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);