[libvirt-users] [help] How to modify the vgamem value ?

Dear everyone Do you know how to modify vgamem value in the .xml file ? such as :<video> <model type='qxl' ram='65536' vram='65536' vgamem='16384' heads='1'/> // from instance-0000015e.xml <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/</video> I plan to increase the volume of vgamem , but it seems that always keep the original value ‘16384’. Was it limited by QEMU? or others？ Please tell me how I can I modify it ? it's better that help me to make a example for modifing the vgamem..... Thank you very much Best Regards .