dbs-virtio-devices: add metrics for net device

[lisongqian]

add metrics for net device and add read_config/write_config return type for the cfg_fails metric.

Fixes: https://github.com/kata-containers/kata-containers/issues/7248

[codecov[bot]]

Codecov Report

Merging #298 (3eb593f) into main (5fbf260) will decrease coverage by 0.67%. The diff coverage is 49.85%.

@@            Coverage Diff             @@
##             main     #298      +/-   ##
==========================================
- Coverage   90.44%   89.77%   -0.67%     
==========================================
  Files          82       83       +1     
  Lines       24597    24846     +249     
==========================================
+ Hits        22246    22306      +60     
- Misses       2351     2540     +189     

Flag	Coverage Δ
dbs-address-space	95.30% <ø> (ø)
dbs-allocator	94.98% <ø> (ø)
dbs-arch	96.37% <100.00%> (ø)
dbs-boot	94.90% <ø> (ø)
dbs-device	92.95% <ø> (ø)
dbs-interrupt	90.42% <100.00%> (ø)
dbs-legacy-devices	73.01% <0.00%> (-19.77%)	:arrow_down:
dbs-miniball	∅ <ø> (∅)
dbs-upcall	94.31% <100.00%> (ø)
dbs-utils	91.25% <ø> (ø)
dbs-virtio-devices	86.66% <61.76%> (-0.69%)	:arrow_down:

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
crates/dbs-legacy-devices/src/cmos.rs	0.00% <0.00%> (ø)
crates/dbs-legacy-devices/src/lib.rs	100.00% <ø> (ø)
crates/dbs-upcall/src/lib.rs	97.92% <ø> (ø)
crates/dbs-virtio-devices/src/vsock/backend/mod.rs	5.88% <0.00%> (-4.12%)	:arrow_down:
...bs-virtio-devices/src/vsock/backend/unix_stream.rs	75.90% <0.00%> (-19.56%)	:arrow_down:
...s/dbs-virtio-devices/src/vsock/muxer/muxer_impl.rs	87.26% <50.00%> (-4.76%)	:arrow_down:
crates/dbs-virtio-devices/src/balloon.rs	80.61% <72.41%> (-0.84%)	:arrow_down:
crates/dbs-virtio-devices/src/mmio/mmio_v2.rs	93.42% <80.00%> (-0.21%)	:arrow_down:
crates/dbs-virtio-devices/src/device.rs	91.78% <88.88%> (-0.50%)	:arrow_down:
crates/dbs-virtio-devices/src/net.rs	85.67% <89.28%> (-0.05%)	:arrow_down:
... and 10 more

... and 1 file with indirect coverage changes

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[studychao]

@lisongqian Please finish review process of this PR before this week, otherwise you should raise the PR in Kata Container repo.

[lisongqian]

Commit log's tittle should not be wrapped and you need to add issue's id above you sob, like:↳

Fixes: #xxxx

Fixed.

[lisongqian]

@lisongqian Please finish review process of this PR before this week, otherwise you should raise the PR in Kata Container repo.↳

Thanks for your reminder. I will finish ASAP.

[studychao]

Also, could you rebase this PR to the latest main?

[lisongqian]

Also, could you rebase this PR to the latest main?↳

Rebased.