host: make system blob memory work on macOS - #182
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Friendly ping @gurchetansingh @jmacnak for reviewing. |
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@jmacnak knows this code well, would be the right person to review |
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With system blobs, host visible memory is shared memory imported as a host pointer, and Metal cannot bind a tiled image to that. A device that reports one unified memory type, as kosmickrisp does, then has nowhere to put an image, and kk_image_plane_bind asserts on the first one. Add a guest only type in that case: device local, allocating from the same host type without host visible emulation. A tiled image is offered that type alone, since the host visible one cannot hold it; a linear image may still use either. MoltenVK reports a device local only type of its own, so nothing changes there. The type goes first, not last: the spec requires a memory type whose flags are a strict subset of another's to sit at a lower index, and device local alone is a subset of every host visible type here. Metal is what makes this the common case, so it is behind __APPLE__.
System blob memory is named shared-memory-vk-N with a per process counter and opened without O_EXCL. A server that is killed leaves its objects behind, the next one reuses the names, and on macOS an object that already has a size cannot be resized: ftruncate fails with EINVAL and vkAllocateMemory fails. Put the pid in the name, and on Apple unlink the object as soon as it exists; the descriptor keeps it alive and is what the guest is handed.
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Two host fixes for running the guest Vulkan driver through kumquat on macOS.
Both only take effect with SystemBlob enabled.
vulkan: add a guest only device local memory type when the host reports a
single host visible unified type. Metal cannot bind a tiled image to an
imported host pointer; this gives images ordinary device memory. Unit test
added.
base: put the pid in the shared memory name and unlink it on creation, so a
killed server does not leave objects that make the next ftruncate fail.
Tested with bazel test //host/vulkan:gfxstream_emulatedphysicalmemory_tests,
and vulkaninfo, vkcube and a dEQP-VK smoke run on kosmickrisp and MoltenVK.