Backport qemu virtio-pmem support merged upstream (git log 7b9829bc6c7d84056c3a1c60737f71db4d2871e4..207efa18ac9eb7085a44cad24489d0da54bc5f65).
QEMU has been recently split into sub-components and as a one-time operation to avoid breakage of tools, we are setting the QEMU sub-component of this BZ to "General". Please review and change the sub-component if necessary the next time you review this BZ. Thanks
virtio-pmem still has a known preflush issue in the upstream kernel, which has to be sorted out upstream first.
As the author of virtio-pmem is no longer working at Red Hat, we won't be supporting virtio-pmem in RHEL8 and will disable it in RHEL9 until we have an upstream fix.
Until then, we really can't test and support this in QEMU.