TFU units is doing a readahead of 64 bytes. This is causing invalid read
MMU errors that can be observed at the nightly full Vulkan runs on
Broadcom devices.
04:13:59.969: [ 85.623205] v3d 1002000000.v3d: MMU error from client TLB (3) at 0x4869000, pte invalid
04:14:05.408: [ 91.019321] v3d 1002000000.v3d: MMU error from client TLB (3) at 0x5209000, pte invalid
04:14:05.413: [ 91.031662] v3d 1002000000.v3d: MMU error from client TLB (3) at 0x7521000, pte invalid
Although the log reports the TLB the real culprit is the TFU. A fix
to the kernel was submitted to fix AXI ID on V3D 4.2 and 7.1
So doing an over-allocation of 64-bytes at v3dv_AllocateMemory is
the simplest method to make these MMU errors itp disapear.
Running ./deqp-vk for an hour, we can see that ~%40 of allocations
would need an extra page (4096 bytes) to accomodate this 64 bytes
padding.
Fixes: ca330f7f04 ("v3dv: implement VK_EXT_memory_budget")
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34475>
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