I forgot to include this brief information about this patch series.
This patch series contains the implementation of a new device driver, hyper_dmabuf, which provides a method for DMA-BUF sharing across different OSes running on the same virtual OS platform powered by a hypervisor.
Detailed information about this driver is described in a high-level doc added by the second patch of the series.
[RFC PATCH 02/60] hyper_dmabuf: added a doc for hyper_dmabuf sharing
I am attaching 'Overview' section here as a summary.
------------------------------------------------------------------------------ Section 1. Overview ------------------------------------------------------------------------------
Hyper_DMABUF driver is a Linux device driver running on multiple Virtual achines (VMs), which expands DMA-BUF sharing capability to the VM environment where multiple different OS instances need to share same physical data without data-copy across VMs.
To share a DMA_BUF across VMs, an instance of the Hyper_DMABUF drv on the exporting VM (so called, “exporter”) imports a local DMA_BUF from the original producer of the buffer, then re-exports it with an unique ID, hyper_dmabuf_id for the buffer to the importing VM (so called, “importer”).
Another instance of the Hyper_DMABUF driver on importer registers a hyper_dmabuf_id together with reference information for the shared physical pages associated with the DMA_BUF to its database when the export happens.
The actual mapping of the DMA_BUF on the importer’s side is done by the Hyper_DMABUF driver when user space issues the IOCTL command to access the shared DMA_BUF. The Hyper_DMABUF driver works as both an importing and exporting driver as is, that is, no special configuration is required. Consequently, only a single module per VM is needed to enable cross-VM DMA_BUF exchange.
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There is a git repository at github.com where this series of patches are all integrated in Linux kernel tree based on the commit:
commit ae64f9bd1d3621b5e60d7363bc20afb46aede215 Author: Linus Torvalds torvalds@linux-foundation.org Date: Sun Dec 3 11:01:47 2017 -0500
Linux 4.15-rc2
https://github.com/downor/linux_hyper_dmabuf.git hyper_dmabuf_integration_v3