Hi all, This is an early attempt to have backends support dynamic fd mapping into shared memory regions. As such, there are a few things that need settling, so I wanted to post this first to have some early feedback.
The usecase for this is, e.g., to support vhost-user-gpu RESOURCE_BLOB operations, or DAX Window request for virtio-fs. In general, any operation where a backend would need to mmap an fd to a shared memory so that the guest can access it. The request will be processed by the VMM, that will, in turn, trigger a mmap with the instructed parameters (i.e., shmid, shm_offset, fd_offset, fd, lenght). As there are already a couple devices that could benefit of such a feature, and more could require it in the future, my intention was to make it generic. To that end, I declared the shared memory region list in `VirtIODevice`. I could add a couple commodity functions to add new regions to the list, so that the devices can use them. But I wanted to gather some feedback before refining it further, as I am probably missing some required steps/or security concerns that I am not taking into account. Albert Esteve (1): vhost-user: add shmem mmap request docs/interop/vhost-user.rst | 23 ++++++++ hw/virtio/vhost-user.c | 106 ++++++++++++++++++++++++++++++++++++ hw/virtio/virtio.c | 2 + include/hw/virtio/virtio.h | 3 + 4 files changed, 134 insertions(+) -- 2.44.0
