Indirect desc

[ShadowCurse]

Changes

Add support for INDIRECT_DESC for IoVecBuff/Mut and enabled VIRTIO_RING_F_INDIRECT_DESC flag for virtio-net device. This feature allows guest to create more buffers for packets which in turn should help with throughput when all available descriptors are used.

Reason

Should help with network performance.

Note

This PR is built on top of #4658, so needs to be merged after it.

License Acceptance

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license. For more information on following Developer Certificate of Origin and signing off your commits, please check CONTRIBUTING.md.

PR Checklist

• [ ] If a specific issue led to this PR, this PR closes the issue.
• [ ] The description of changes is clear and encompassing.
• [ ] Any required documentation changes (code and docs) are included in this PR.
• [ ] API changes follow the Runbook for Firecracker API changes.
• [ ] User-facing changes are mentioned in CHANGELOG.md.
• [ ] All added/changed functionality is tested.
• [ ] New TODOs link to an issue.
• [ ] Commits meet contribution quality standards.

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• [ ] This functionality cannot be added in rust-vmm.