Add a test that verifies virtio-net device reset works end-to-end by
unbinding and rebinding the guest driver and checking the device
remains functional and MMDS is still reachable.

Suggested-by: Adam Jensen <adam@acj.sh>
Signed-off-by: Ilias Stamatis <ilstam@amazon.com>

Add a test that verifies virtio-block device reset works end-to-end by
unbinding and rebinding the guest driver for a scratch block device
and checking the device remains functional.

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>

Pmem does not have any backend specific state that needs resetting so
implement the _reset() method by simply returning true. The rest of the
state is handled by the generic reset().

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>

Add a test that verifies virtio-pmem device reset works end-to-end by
unbinding and rebinding the guest driver and checking the device
remains functional.

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>

Implement the _reset() method for the virtio-balloon device, resetting
the balloon specific state in-place. Do not deflate the balloon on
reset.

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>

Add a test that verifies virtio-balloon device reset works end-to-end
by unbinding and rebinding the guest driver and checking the device
remains functional.

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>

The entropy device does not have any backend specific state that needs
resetting so implement the _reset() method by simply returning true.

The test_failed_reset_blocks_reinitialization() test used an entropy
device assuming it doesn't support reset. Since it now does, adjust the
test to check that the device is first deactivated after a reset and
then the driver can perform the initialization sequence again.

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>

Add a test that verifies virtio-rng device reset works end-to-end by
unbinding and rebinding the guest driver and checking the device
remains functional.

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>

Register the muxer's host socket epoll listener when the device is
activated rather than when the muxer is constructed, by adding an
activate() method to the VsockBackend trait and calling it from
Vsock::activate().

This ties the listener's lifetime to device activation instead of muxer
construction. This lays the groundwork for device reset, which needs the
listener set to be re-established on each activation.

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>

Implement the _reset() method for the virtio-vsock device, resetting the
vsock specific state in-place. Add epoll_ctl to the vCPU seccomp filter,
since it's needed to remove the vsock muxer's connection and listener
epoll listeners when the device is reset.

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>

Add a test that verifies virtio-vsock device reset works end-to-end by
unbinding and rebinding the guest driver and checking the device
remains functional.

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>

The virtio-mem device does not have any backend specific state that
needs resetting so implement the _reset() method by simply returning
true. Plugged memory regions remain intact.

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>

Add a test that verifies virtio-mem device reset works end-to-end by
unbinding and rebinding the guest driver and checking the device remains
functional.

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>

firecracker-microvm#5891

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>