On 18. 3. 2020 16:47, Andrea Bolognani wrote:
On Mon, 2020-03-09 at 18:04 +0000, Daniel P. Berrangé wrote:
At a high level the embedded QEMU driver
- Isolated from any other instance of the QEMU driver
Replying here because it looks as good a place as any.
Now that Michal has made it so that identically-name domains defined under different qemu:///embed roots no longer clash at the machined level (thanks!), I have immediately bumped into the next issue: if I use either one of
<memoryBacking> <hugepages/> </memoryBacking>
<memoryBacking> <access mode='shared'/> </memoryBacking>
both qemu:///embed instances try to use the same paths:
/dev/hugepages/libvirt/qemu/$domid-$domname/
/dev/shm/libvirt/qemu/$domid-$domname/
This is because qemu driver uses virDomainDefGetShortName() to construct the path which is not embed driver aware. In fact, we use it on a few other places: libvirt.git $ git grep -C0 virDomainDefGetShortName -- src/qemu/ \ | wc -l 15 so we probably have more broken plaes. I will investigate and post a patch. Probably something among those lines that fixed machined name generation.
which obviously breaks everything.
In this case, is the application expected to set
hugetlbfs_mount = "/dev/hugepages/$random"
memory_backing_dir = "/dev/shm/$random"
in qemu.conf beforehand (I'm not sure the former setting would even work), or should libvirt take care of it automatically in a similar way it now does for machine names?
The latter is true. Michal