| Developing with libvfio-user |
| ============================ |
| |
| The API is currently documented via the [libvfio-user header file](../include/libvfio-user.h), |
| along with some additional [documentation](./). |
| |
| The library is actively under development, and should not yet be considered a |
| stable API/ABI. |
| |
| The protocol itself can be considered stable and will not break backwards |
| compatibility. See the QEMU repository for the [canonical protocol |
| definition](https://www.qemu.org/docs/master/interop/vfio-user.html). |
| |
| The API is not thread safe, but individual `vfu_ctx_t` handles can be |
| used separately by each thread: that is, there is no global library state. |
| |
| See [Accessing memory with libvfio-user](memory-mapping.md) for more details on |
| how to manage memory. |
| |
| See [Examples](examples.md) for some simple examples of using the library. |
| |
| Supported features |
| ------------------ |
| |
| With the client support found in |
| [cloud-hypervisor](https://github.com/cloud-hypervisor/cloud-hypervisor/) or |
| [qemu](https://gitlab.com/qemu-project/qemu), most guest VM use cases will work. |
| |
| However, guests with an IOMMU (vIOMMU) will not currently work: the number of |
| DMA regions is strictly limited, and there are also issues with some server |
| implementations such as SPDK's virtual NVMe controller. |
| |
| Currently, `libvfio-user` has explicit support for PCI devices only. In |
| addition, only PCI endpoints are supported (no bridges etc.). |
| |
| Live migration |
| -------------- |
| |
| The `master` branch of `libvfio-user` implements live migration with a protocol |
| based on vfio's v2 protocol. Currently, there is no support for this in any qemu |
| client. Contributions are welcome! |
