restrictions for virtiofs (related to commit: 88957116c9 for libvirt 6.9.0)

Michal Privoznik mprivozn at
Mon Oct 5 08:50:08 UTC 2020

On 10/3/20 1:15 AM, Masayoshi Mizuma wrote:
> On Fri, Oct 02, 2020 at 11:31:32AM -0400, Masayoshi Mizuma wrote:
>> Hello Jan, and Michal,
>> commit: 88957116c9 ("qemu: Use memory-backend-* for regular guest memory") gets
>> the system memory sharable without numa config.
>> The qemu options with the patch will be like as:
>>    -machine pc-q35-5.2,accel=kvm,usb=off,vmport=off,smm=on,dump-guest-core=off,memory-backend=pc.ram \
>>    -object memory-backend-file,id=pc.ram,mem-path=/var/lib/libvirt/qemu/ram/2-Test/pc.ram,share=yes,size=17179869184 \
>> So, we can remove the numa restriction of virtiofs, right?
>> The patch to remove that is the bottom of this email.
>> And, 88957116c9 seems to introduce another restriction which we
>> cannot create numa nodes on the machine. I got the following
>> message when I set the numa config and started the VM:
>>     2020-10-02T00:31:46.780374Z qemu-system-x86_64: '-machine memory-backend' and '-numa memdev' properties are mutually exclusive
> It seems that this isn't a restriction for virtiofs. It's a bug introduced
> by commit: 88957116c9. <numa> element doesn't work regardless of virtiofs config...

Do you have domain XML that is failing?


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