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Native context support is implemented by diverting the libdrm_amdgpu functions into new functions that use virtio-gpu. VA allocations are done directly in the guest, using newly exposed libdrm_amdgpu helpers (retrieved through dlopen/dlsym). Guest <-> Host roundtrips can be expensive so we try to avoid them as much as possible. When possible we also don't wait for the host reply in case where it's not needed to get correct result. Implicit sync works because virtio-gpu commands are submitted in order to the host (there a single queue per device, shared by all the guest processes). virtio-gpu also only supports one context per file description (but multiple file descriptions per process) while amdgpu only allows one fd per process, but multiple contexts per fd. This causes synchronization problems, because virtio-gpu drops all sync primitive if they belong to the same fd/context/ring: ie the amdgpu_ctx can't be expressed in virtio-gpu terms. For now the solution is to only allocate a single amdgpu_ctx per application. Contrary to radeonsi/radv, amdgpu_virtio can use libdrm_amdgpu directly: the ones that don't rely on ioctl() are safe to use here. Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> Reviewed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> Reviewed-by: Marek Olšák <marek.olsak@amd.com> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21658>
`Mesa <https://mesa3d.org>`_ - The 3D Graphics Library ====================================================== Source ------ This repository lives at https://gitlab.freedesktop.org/mesa/mesa. Other repositories are likely forks, and code found there is not supported. Build & install --------------- You can find more information in our documentation (`docs/install.rst <https://docs.mesa3d.org/install.html>`_), but the recommended way is to use Meson (`docs/meson.rst <https://docs.mesa3d.org/meson.html>`_): .. code-block:: sh $ meson setup build $ ninja -C build/ $ sudo ninja -C build/ install Support ------- Many Mesa devs hang on IRC; if you're not sure which channel is appropriate, you should ask your question on `OFTC's #dri-devel <irc://irc.oftc.net/dri-devel>`_, someone will redirect you if necessary. Remember that not everyone is in the same timezone as you, so it might take a while before someone qualified sees your question. To figure out who you're talking to, or which nick to ping for your question, check out `Who's Who on IRC <https://dri.freedesktop.org/wiki/WhosWho/>`_. The next best option is to ask your question in an email to the mailing lists: `mesa-dev\@lists.freedesktop.org <https://lists.freedesktop.org/mailman/listinfo/mesa-dev>`_ Bug reports ----------- If you think something isn't working properly, please file a bug report (`docs/bugs.rst <https://docs.mesa3d.org/bugs.html>`_). Contributing ------------ Contributions are welcome, and step-by-step instructions can be found in our documentation (`docs/submittingpatches.rst <https://docs.mesa3d.org/submittingpatches.html>`_). Note that Mesa uses gitlab for patches submission, review and discussions.