Bug 2086384

Description of problem:
As subject

Version-Release number of selected component (if applicable):
libvirt-8.3.0-1.el9.x86_64

How reproducible:
100%

Steps to Reproduce:
1. Emulate pmem and mmcblk by QEMU. And check these node devices
i. Start a RHEL9 VM with these XML:
<domain type='kvm' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>
  <maxMemory slots='16' unit='KiB'>4097152</maxMemory>
...
  <cpu mode='host-model' check='partial'>
    <numa>
      <cell id='0' cpus='0-1' memory='2095104' unit='KiB'/>
    </numa>
  </cpu>
...
  <devices>
...
    <memory model='virtio-pmem' access='shared'>
      <source>
        <path>/tmp/virtio_pmem</path>
      </source>
      <target>
        <size unit='KiB'>524288</size>
      </target>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x0a' function='0x0'/>
    </memory>
  </devices>
  <qemu:commandline>
    <qemu:arg value='-device'/>
    <qemu:arg value='sdhci-pci,id=sdhci,bus=pci.0,addr=0xf'/>
    <qemu:arg value='-device'/>
    <qemu:arg value='sd-card,drive=mydrive'/>
    <qemu:arg value='-drive'/>
    <qemu:arg value='id=mydrive,if=none,format=raw,file=/tmp/sdcard'/>
  </qemu:commandline>

ii. Check the block:
[root@localhost ~]# lsblk
NAME          MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
mmcblk0       179:0    0   128M  0 disk 
vda           252:0    0    10G  0 disk 
├─vda1        252:1    0     1G  0 part /boot
└─vda2        252:2    0     9G  0 part 
  ├─rhel-root 253:0    0     8G  0 lvm  /
  └─rhel-swap 253:1    0     1G  0 lvm  [SWAP]
pmem0         259:0    0 511.9M  1 disk 

[root@localhost ~]# udevadm info --name mmcblk0
P: /devices/pci0000:00/0000:00:0f.0/mmc_host/mmc0/mmc0:4567/block/mmcblk0
N: mmcblk0
L: 0
S: disk/by-id/mmc-QEMU__0xdeadbeef
E: DEVPATH=/devices/pci0000:00/0000:00:0f.0/mmc_host/mmc0/mmc0:4567/block/mmcblk0
E: DEVNAME=/dev/mmcblk0
E: DEVTYPE=disk
E: DISKSEQ=3
E: MAJOR=179
E: MINOR=0
E: SUBSYSTEM=block
E: USEC_INITIALIZED=15106162
E: ID_SERIAL=0xdeadbeef
E: ID_NAME=QEMU_
E: DEVLINKS=/dev/disk/by-id/mmc-QEMU__0xdeadbeef
E: TAGS=:systemd:
E: CURRENT_TAGS=:systemd:

[root@localhost ~]# udevadm info --name pmem0
P: /devices/LNXSYSTM:00/LNXSYBUS:00/ACPI0012:00/ndbus0/region0/namespace0.0/block/pmem0
N: pmem0
L: 0
E: DEVPATH=/devices/LNXSYSTM:00/LNXSYBUS:00/ACPI0012:00/ndbus0/region0/namespace0.0/block/pmem0
E: DEVNAME=/dev/pmem0
E: DEVTYPE=disk
E: DISKSEQ=2
E: MAJOR=259
E: MINOR=0
E: SUBSYSTEM=block
E: USEC_INITIALIZED=14732010
E: TAGS=:systemd:
E: CURRENT_TAGS=:systemd:

iii. Check the node devices:
[root@localhost ~]# virsh nodedev-list --cap storage
block_vda

No mmcblk and peme devices.


2. For mtdblock device, since the kernel config of RHEL9(5.14.0-90.el9.x86_64) is "CONFIG_MTD=m, CONFIG_MTD_BLOCK=m, CONFIG_MTD_RAM not set. It cannot emulated by kernel in RHEL9. So I test it on Fedora rawhide(5.17.4-300.fc36.x86_64, libvirt-8.3.0-1.fc37.x86_64)
i. Emulate mtdblock device
# modprobe mtdram total_size=200 erase_size=100
# modprobe mtdblock

ii. Check mtdblock by lsblk, udev and virsh.
➜  ~ lsblk
NAME      MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
mtdblock0  31:0    0  200K  0 disk 
vda       252:0    0   80G  0 disk 
└─vda1    252:1    0   80G  0 part /
vdb       252:16   0    5G  0 disk /mnt

➜  ~ udevadm info --name mtdblock0                                       
P: /devices/virtual/mtd/mtd0/mtdblock0
M: mtdblock0
R: 0
U: block
T: disk
D: b 31:0
N: mtdblock0
L: 0
Q: 11
E: DEVPATH=/devices/virtual/mtd/mtd0/mtdblock0
E: DEVNAME=/dev/mtdblock0
E: DEVTYPE=disk
E: DISKSEQ=11
E: MAJOR=31
E: MINOR=0
E: SUBSYSTEM=block
E: USEC_INITIALIZED=1724723462880
E: TAGS=:systemd:
E: CURRENT_TAGS=:systemd:

➜  ~ virsh nodedev-list --cap storage         
block_vda_230c9ab9_9ea9_433d_8
block_vdb

No mtdblock listed by virsh.

Actual results:
As above

Expected results:
Libvirt node device could list mtdblock, mmcblk, pmem devices.

Additional info:
See also: Bug 2045953 - 'virsh nodedev-list --cap storage' doesn't list host nvme storage