On Thu, Feb 13, 2025 at 01:19:53PM -0500, Laine Stump wrote:
The result is that you can now have:
<interface type='vhostuser'> <backend type='passt'/> ... </interface>
Then as long as you also have the following as a subelement of <domain>:
<memoryBacking> <access mode='shared'/> </memoryBacking>
your passt interfaces will benefit from the greatly improved efficiency of a vhost-user data path
The presence of this element is not validated anywhere though, so if you leave it out the network interface will just silently be non-functional. I don't think that makes for a good user experience. How does passt know where the backing file is located in the first place? It's not passed on its command line, and I didn't spot any logic to hand the information over. This part clearly works, I just don't understand how :)
+++ b/src/conf/domain_validate.c @@ -2163,7 +2163,8 @@ virDomainNetDefValidate(const virDomainNetDef *net) return -1; }
- if (net->type != VIR_DOMAIN_NET_TYPE_USER) { + if (net->type != VIR_DOMAIN_NET_TYPE_USER && + net->type != VIR_DOMAIN_NET_TYPE_VHOSTUSER) { if (net->backend.type == VIR_DOMAIN_NET_BACKEND_PASST) { virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("The 'passt' backend can only be used with interface type='user'"));
This error message needs to be updated.
+++ b/tests/qemuxmlconfdata/net-vhostuser-passt.x86_64-latest.args @@ -0,0 +1,42 @@ +LC_ALL=C \ +PATH=/bin \ +HOME=/var/lib/libvirt/qemu/domain--1-QEMUGuest1 \ +USER=test \ +LOGNAME=test \ +XDG_DATA_HOME=/var/lib/libvirt/qemu/domain--1-QEMUGuest1/.local/share \ +XDG_CACHE_HOME=/var/lib/libvirt/qemu/domain--1-QEMUGuest1/.cache \ +XDG_CONFIG_HOME=/var/lib/libvirt/qemu/domain--1-QEMUGuest1/.config \ +/usr/bin/qemu-system-x86_64 \ +-name guest=QEMUGuest1,debug-threads=on \ +-S \ +-object '{"qom-type":"secret","id":"masterKey0","format":"raw","file":"/var/lib/libvirt/qemu/domain--1-QEMUGuest1/master-key.aes"}' \ +-machine pc,usb=off,dump-guest-core=off,memory-backend=pc.ram,acpi=off \ +-accel tcg \ +-cpu qemu64 \ +-m size=219136k \ +-object '{"qom-type":"memory-backend-ram","id":"pc.ram","size":224395264}' \ +-overcommit mem-lock=off \ +-smp 1,sockets=1,cores=1,threads=1 \ +-uuid c7a5fdbd-edaf-9455-926a-d65c16db1809 \ +-display none \ +-no-user-config \ +-nodefaults \ +-chardev socket,id=charmonitor,fd=1729,server=on,wait=off \ +-mon chardev=charmonitor,id=monitor,mode=control \ +-rtc base=utc \ +-no-shutdown \ +-boot strict=on \ +-blockdev '{"driver":"host_device","filename":"/dev/HostVG/QEMUGuest1","node-name":"libvirt-1-storage","read-only":false}' \ +-device '{"driver":"ide-hd","bus":"ide.0","unit":0,"drive":"libvirt-1-storage","id":"ide0-0-0","bootindex":1}' \ +-chardev socket,id=charnet0,path=/var/run/libvirt/qemu/passt/-1-QEMUGuest1-net0.socket \ +-netdev '{"type":"vhost-user","chardev":"charnet0","id":"hostnet0"}' \ +-device '{"driver":"virtio-net-pci","netdev":"hostnet0","id":"net0","mac":"00:11:22:33:44:55","bus":"pci.0","addr":"0x2"}' \ +-chardev socket,id=charnet1,path=/var/run/libvirt/qemu/passt/-1-QEMUGuest1-net1.socket \ +-netdev '{"type":"vhost-user","chardev":"charnet1","id":"hostnet1"}' \ +-device '{"driver":"virtio-net-pci","netdev":"hostnet1","id":"net1","mac":"00:11:22:33:44:11","bus":"pci.0","addr":"0x3"}' \ +-chardev socket,id=charnet2,path=/var/run/libvirt/qemu/passt/-1-QEMUGuest1-net2.socket \ +-netdev '{"type":"vhost-user","chardev":"charnet2","id":"hostnet2"}' \ +-device '{"driver":"virtio-net-pci","netdev":"hostnet2","id":"net2","mac":"00:11:22:33:44:11","bus":"pci.0","addr":"0x4"}' \ +-audiodev '{"id":"audio1","driver":"none"}' \ +-sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny \ +-msg timestamp=on
It's a real shame that we don't have a way to include the command line for external programs (swtpm, passt) in the corresponding test case... -- Andrea Bolognani / Red Hat / Virtualization