KVM: arm64: vgic-v3: Fix some error codes when setting RDIST base

KVM_DEV_ARM_VGIC_GRP_ADDR group doc says we should return
-EEXIST in case the base address of the redist is already set.
We currently return -EINVAL.

However we need to return -EINVAL in case a legacy REDIST address
is attempted to be set while REDIST_REGIONS were set. This case
is discriminated by looking at the count field.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210405163941.510258-2-eric.auger@redhat.com

diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c
index 15a6c98..ef9baf0 100644 (file)
--- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c
+++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c
@@ -791,10 +791,6 @@ static int vgic_v3_insert_redist_region(struct kvm *kvm, uint32_t index,
        size_t size = count * KVM_VGIC_V3_REDIST_SIZE;
        int ret;
 
-       /* single rdist region already set ?*/
-       if (!count && !list_empty(rd_regions))
-               return -EINVAL;
-
        /* cross the end of memory ? */
        if (base + size < base)
                return -EINVAL;
@@ -805,11 +801,15 @@ static int vgic_v3_insert_redist_region(struct kvm *kvm, uint32_t index,
        } else {
                rdreg = list_last_entry(rd_regions,
                                        struct vgic_redist_region, list);
-               if (index != rdreg->index + 1)
+
+               /* Don't mix single region and discrete redist regions */
+               if (!count && rdreg->count)
                        return -EINVAL;
 
-               /* Cannot add an explicitly sized regions after legacy region */
-               if (!rdreg->count)
+               if (!count)
+                       return -EEXIST;
+
+               if (index != rdreg->index + 1)
                        return -EINVAL;
        }