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Add comprehensive documentation for the Vhost framework, which serves as the VirtIO backend implementation in NuttX for cross-core communication. The documentation includes: - Overview and comparison with Linux Vhost and QEMU VirtIO Device - Three-layer architecture (Service, Framework, Transport) - Driver/Device registration and matching workflow - Source code directory structure - Complete API reference (data structures, core APIs, macro APIs) Signed-off-by: Bowen Wang <wangbowen6@xiaomi.com>
56 lines
1.5 KiB
ReStructuredText
56 lines
1.5 KiB
ReStructuredText
=====
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Vhost
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=====
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Vhost is the backend implementation of VirtIO in NuttX. While in standard
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Linux kernel, Vhost is a technology for improving virtual machine I/O
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performance by offloading VirtIO device data plane processing, NuttX extends
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this concept for cross-core communication scenarios.
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In NuttX, Vhost is defined as a complete VirtIO backend implementation. It
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works with VirtIO frontend through Vhost-Rptun/PCI <-> VirtIO-Rptun/PCI to
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achieve cross-core communication. Essentially, Vhost in NuttX is a complete
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implementation of VirtIO Device, similar to VirtIO Device implementation in
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QEMU.
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Comparison
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==========
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The following table compares NuttX Vhost with Linux Vhost and QEMU VirtIO
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Device:
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.. list-table::
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:header-rows: 1
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:widths: 25 25 25 25
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* - Dimension
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- NuttX Vhost
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- Linux Vhost
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- QEMU VirtIO Device
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* - Use Case
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- Cross-core communication
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- Virtualization performance
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- Virtualization
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* - Transport Support
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- Rptun and PCI
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- MMIO and PCI
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- MMIO and PCI
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* - Data Plane
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- Included
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- Included
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- Included
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* - Control Plane
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- Included
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- Not included (by Hypervisor)
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- Included
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Vhost and VirtIO are complementary concepts, representing the "backend" and
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"frontend" relationship. In cross-core communication scenarios, one side acts
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as the "frontend" (VirtIO Driver) and the other side acts as the "backend"
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(Vhost Driver, i.e., VirtIO Device implementation).
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.. toctree::
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:maxdepth: 1
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:caption: Contents
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framework
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