Add iommufd case for vfio_net_boot

[fanchen2]

iommufd-backed VFIO, for example:
-object iommufd,id=iommufd0
-device vfio-pci,host=01:00.0,iommufd=iommufd0
Multiple pcie device can use the same iommufd.

[xhao22]

Glad to see it covers both VFIO legacy backend and IOMMFD backend for Qemu vfio-pci device.

[PaulYuuu]

Hello @fanchen2, thank you for the PR. I see avocado-framework/avocado-vt#4004, will help to review both.

Cc @JinLiul, as you may also be interesting with this.

[PaulYuuu]

OK, let's wait for the avocado-vt patch to be merged, then we can merge this one.

Also, thank you for your contribution.

[PaulYuuu]

Hello @fanchen2, I will merge this PR once all CI checks succeed. But some tips for you:

1. Do not use master as the branch to contribute.
2. tp-qemu requires gpg-signed commit.
3. tp-qemu supports to use pre-commit to format code locally.

Thank you for the first contribution.

[PaulYuuu]

@fanchen2 btw, can you provide test results?

[fanchen2]

@PaulYuuu Yes, yes, thank you.
I just found the branch issue, I closed it by mistake, sorry to reopen.
This is the test result for single PF, only one NIC device available on my system for testing now, is that OK?

[root@emr-120485 ~]# avocado run --vt-config /root/avocado/data/avocado-vt/backends/qemu/cfg/nic.cfg
JOB ID : c6f480c845cc848a081cf4b29b7159202e11745f
JOB LOG : /root/avocado/job-results/job-2024-11-08T16.55-c6f480c/job.log
(1/1) type_specific.myprovider.vfio_net_boot.default.default.iommufd.ipv4.pf.one_nic.single_vm: STARTED
(1/1) type_specific.myprovider.vfio_net_boot.default.default.iommufd.ipv4.pf.one_nic.single_vm: PASS (54.11 s)
RESULTS : PASS 1 | ERROR 0 | FAIL 0 | SKIP 0 | WARN 0 | INTERRUPT 0 | CANCEL 0
JOB TIME : 55.11 s
[root@emr-120485 ~]# avocado run --vt-config /root/avocado/data/avocado-vt/backends/qemu/cfg/nic.cfg
JOB ID : bc496010345039068cc6d39e7d555548f1eda58c
JOB LOG : /root/avocado/job-results/job-2024-11-08T16.58-bc49601/job.log
(1/1) type_specific.myprovider.vfio_net_boot.default.default.multi_iommufd.ipv4.pf.one_nic.single_vm: STARTED
(1/1) type_specific.myprovider.vfio_net_boot.default.default.multi_iommufd.ipv4.pf.one_nic.single_vm: PASS (54.26 s)
RESULTS : PASS 1 | ERROR 0 | FAIL 0 | SKIP 0 | WARN 0 | INTERRUPT 0 | CANCEL 0
JOB TIME : 55.23 s