diff --git a/libvirt/tests/cfg/sriov/vIOMMU/intel_iommu_with_dma_translation.cfg b/libvirt/tests/cfg/sriov/vIOMMU/intel_iommu_with_dma_translation.cfg
index ed796ca749..15411a02ec 100644
--- a/libvirt/tests/cfg/sriov/vIOMMU/intel_iommu_with_dma_translation.cfg
+++ b/libvirt/tests/cfg/sriov/vIOMMU/intel_iommu_with_dma_translation.cfg
@@ -13,5 +13,4 @@
             with_more_vcpus = "yes"
             dma_translation = "off"
             eim_dict = {'eim': 'on'}
-            guest_vcpus = 256
     iommu_dict = {'model': 'intel', 'driver': {'intremap': 'on', 'caching_mode': 'on', 'iotlb': 'on', 'dma_translation': '${dma_translation}'}}
diff --git a/libvirt/tests/src/sriov/vIOMMU/intel_iommu_with_dma_translation.py b/libvirt/tests/src/sriov/vIOMMU/intel_iommu_with_dma_translation.py
index 4b057ed484..cda4e9e539 100644
--- a/libvirt/tests/src/sriov/vIOMMU/intel_iommu_with_dma_translation.py
+++ b/libvirt/tests/src/sriov/vIOMMU/intel_iommu_with_dma_translation.py
@@ -1,3 +1,4 @@
+from avocado.utils import cpu
 from virttest import virsh
 from virttest.libvirt_xml import vm_xml
 
@@ -23,6 +24,7 @@ def run(test, params, env):
         test_obj.setup_iommu_test(iommu_dict=iommu_dict)
         if with_more_vcpus:
             vmxml = vm_xml.VMXML.new_from_dumpxml(vm_name)
+            guest_vcpus = cpu.online_count()
             vmxml.vcpu = int(guest_vcpus)
             vmxml.sync()
         test.log.info("TEST STEP2: Start the guest.")