KVM: arm64: vgic-v3: Check redist region is not above the VM IPA size

Verify that the redistributor regions do not extend beyond the
VM-specified IPA range (phys_size). This can happen when using
KVM_VGIC_V3_ADDR_TYPE_REDIST or KVM_VGIC_V3_ADDR_TYPE_REDIST_REGIONS
with:

  base + size > phys_size AND base < phys_size

Add the missing check into vgic_v3_alloc_redist_region() which is called
when setting the regions, and into vgic_v3_check_base() which is called
when attempting the first vcpu-run. The vcpu-run check does not apply to
KVM_VGIC_V3_ADDR_TYPE_REDIST_REGIONS because the regions size is known
before the first vcpu-run. Note that using the REDIST_REGIONS API
results in a different check, which already exists, at first vcpu run:
that the number of redist regions is enough for all vcpus.

Finally, this patch also enables some extra tests in
vgic_v3_alloc_redist_region() by calculating "size" early for the legacy
redist api: like checking that the REDIST region can fit all the already
created vcpus.
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Ricardo Koller <ricarkol@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211005011921.437353-3-ricarkol@google.com

arch/arm64/kvm/vgic/vgic-mmio-v3.c

@@ -796,7 +796,9 @@ static int vgic_v3_alloc_redist_region(struct kvm *kvm, uint32_t index,
 	struct vgic_dist *d = &kvm->arch.vgic;
 	struct vgic_redist_region *rdreg;
 	struct list_head *rd_regions = &d->rd_regions;
-	size_t size = count * KVM_VGIC_V3_REDIST_SIZE;
+	int nr_vcpus = atomic_read(&kvm->online_vcpus);
+	size_t size = count ? count * KVM_VGIC_V3_REDIST_SIZE
+			    : nr_vcpus * KVM_VGIC_V3_REDIST_SIZE;
 	int ret;
 
 	/* cross the end of memory ? */
@@ -840,7 +842,7 @@ static int vgic_v3_alloc_redist_region(struct kvm *kvm, uint32_t index,
 
 	rdreg->base = VGIC_ADDR_UNDEF;
 
-	ret = vgic_check_ioaddr(kvm, &rdreg->base, base, SZ_64K);
+	ret = vgic_check_iorange(kvm, rdreg->base, base, SZ_64K, size);
 	if (ret)
 		goto free;
 

arch/arm64/kvm/vgic/vgic-v3.c

@@ -483,8 +483,10 @@ bool vgic_v3_check_base(struct kvm *kvm)
 		return false;
 
 	list_for_each_entry(rdreg, &d->rd_regions, list) {
-		if (rdreg->base + vgic_v3_rd_region_size(kvm, rdreg) <
-			rdreg->base)
+		size_t sz = vgic_v3_rd_region_size(kvm, rdreg);
+
+		if (vgic_check_iorange(kvm, VGIC_ADDR_UNDEF,
+				       rdreg->base, SZ_64K, sz))
 			return false;
 	}