[Virtio-fs] [virtiofsd] Issue opened: virtiofsd-rs dax panic QueueReader(FindMemoryRegion); virtiofsd(qemu) works.

[virtiofs-bot at sinrega.org]

virtiofsd-rs behavior diverges from virtiofsd(qemu).

To reproduce:
boot guest with rootflags=dax with shared dir being a rootfs.
on the guest run:
`env -i -- firefox -headless`

virtiofsd-rs result:
`thread 'vring_worker' panicked at 'called `Result::unwrap()` on an `Err` value: QueueReader(FindMemoryRegion)', src/main.rs:222:18`

Platform used is cloud-hypervisor

As per sources Error(FindMemoryRegion) is associated with "no memory region for this address range"  and  "Failed to find memory region for guest physical address".


This may contribute some information on the issue, or be an unrelated issue:
When using virtiofsd(qemu) with stock cloud-hypervisor, cloud-hypervisor's seccomp kills CH process due to syscall=18 (pwrite64. pread, pwrite - read from or write to a file descriptor at a given offset) apparently being an unexpected syscall which doesn't occur in normal operation. Launching firefox triggers this syscall in the VMM.

Running cloud-hypervisor with --seccomp false and virtiofsd(qemu) results in no observable problems when launching firefox.

Unknown if issue reproduces on qemu.
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https://gitlab.com/virtio-fs/virtiofsd/-/issues/39