Re: CXL volatile memory is not listed

[David Hildenbrand <david@redhat.com>]

On 10.08.23 12:59, Philippe Mathieu-Daudé wrote:
> Hi,
> 
> Cc'ing Igor and David.
> 
> On 9/8/23 00:51, Maverickk 78 wrote:
>> Hello,
>>
>> I am running qemu-system-x86_64
>>
>> qemu-system-x86_64 --version
>> QEMU emulator version 8.0.92 (v8.1.0-rc2-80-g0450cf0897)
>>
>> qemu-system-x86_64 \
>> -m 2G,slots=4,maxmem=4G \
>> -smp 4 \
>> -machine type=q35,accel=kvm,cxl=on \
>> -enable-kvm \
>> -nographic \
>> -device pxb-cxl,id=cxl.0,bus=pcie.0,bus_nr=52 \
>> -device cxl-rp,id=rp0,bus=cxl.0,chassis=0,port=0,slot=0 \
>> -object memory-backend-file,id=mem0,mem-path=/tmp/mem0,size=1G,share=true \
>> -device cxl-type3,bus=rp0,volatile-memdev=mem0,id=cxl-mem0 \
>> -M cxl-fmw.0.targets.0=cxl.0,cxl-fmw.0.size=1G
>>
>>
>> I was expecting the CXL memory to be listed in "System Ram", the lsmem
>> shows only 2G memory which is System RAM, it's not listing the CXL
>> memory.

We are talking about the memory via inside the guest, right?

In the guest, that memory most probably has to be added as "System RAM" 
explicitly using the dax/kmem driver.

https://lwn.net/Articles/922944/

Contains some details on how to use "daxctl reconfigure-device".

-- 
Cheers,

David / dhildenb