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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Eric Auger <eric.auger@redhat.com>,
        Marc Zyngier <maz@kernel.org>,
        Zenghui Yu <yuzenghui@huawei.com>
Subject: [PATCH 5.4 62/96] KVM: arm/arm64: vgic-its: Fix restoration of unmapped collections
Date:   Thu, 13 Feb 2020 07:21:09 -0800
Message-Id: <20200213151903.026499129@linuxfoundation.org>
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From: Eric Auger <eric.auger@redhat.com>

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>

---
 virt/kvm/arm/vgic/vgic-its.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- 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 v
 	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);