KVM: arm/arm64: vgic-its: Fix restoration of unmapped collections

commit 8c58be34494b7f1b2adb446e2d8beeb90e5de65b upstream.

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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 2be6b66b3856dfc0fa1512b1d67c259ba194d01b..f8ad7096555d73e3bb4666f398628f797f9c2d70 100644 (file)
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -2472,7 +2472,8 @@ 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);