QEMU CXL2.0 v4 support

[Raghav Mahajan]

Hi,

                I am running the QEMU with CXL 2.0 MEM device using QEMU of QEMU CXL v4 branch. (https://gitlab.com/bwidawsk/qemu/-/tree/cxl-2.0v4/)

               

                I have used following command to launch QEMU:

                qemu-system-x86_64 -M q35,nvdimm=on -m 8192M -smp 8,sockets=2,cores=2,threads=2 -hda ubuntu-20.10-64.qcow2 -enable-kvm -usbdevice tablet -monitor stdio -object memory-backend-file,id=cxl-mem1,share=on,mem-path=cxl_type_mem,size=512M -object memory-backend-file,id=cxl-lsa,share=on,mem-path=cxl_lsa_mem,size=2M -device pxb-cxl,id=cxl.0,bus=pcie.0,bus_nr=52,uid=0,len-window-base=1,window-base[0]=0x4c0000000,memdev[0]=cxl-mem1 -device cxl-rp,id=rp0,bus=cxl.0,addr=0.0,chassis=0,slot=0 -device cxl-type3,bus=rp0,memdev=cxl-mem1,id=cxl-pmem0,size=256M,lsa=cxl-lsa

              

                I am not able to see PMEM device(persistent memory) in Guest OS for ‘memory-backened-file’ which attached with cxl device(cxl-type3).

                For PMEM device to be visible in Guest OS, is it required for QEMU to populate SRAT/HMAT table with CXL device info?      

 

Thanks,

Raghav Mahajan