Module: Mesa Branch: main Commit: 82bef62c17c79b298601fd565ce558c5282a88b7 URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=82bef62c17c79b298601fd565ce558c5282a88b7
Author: Iago Toral Quiroga <ito...@igalia.com> Date: Mon Oct 16 16:38:31 2023 +0200 v3d,v3dv: fix MMU error from hardware prefetch after ldunifa ldunifa works exactly the same as ldunif: the hw will prefetch the next 4 bytes after a read, so if a buffer is exactly a multiple of a page size and a shader uses ldunifa to read exactly the last 4 bytes the prefetch will read out of bounds and spam the error on the kernel log. Avoid that by allocating extra bytes in this scenario. Reviewed-by: Alejandro Piñeiro <apinhe...@igalia.com> Cc: mesa-stable Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25752> --- src/broadcom/vulkan/v3dv_device.c | 12 ++++++++++++ src/gallium/drivers/v3d/v3d_resource.c | 12 +++++++++++- 2 files changed, 23 insertions(+), 1 deletion(-) diff --git a/src/broadcom/vulkan/v3dv_device.c b/src/broadcom/vulkan/v3dv_device.c index 48aa967e56f..60c55120fe6 100644 --- a/src/broadcom/vulkan/v3dv_device.c +++ b/src/broadcom/vulkan/v3dv_device.c @@ -2766,6 +2766,18 @@ get_buffer_memory_requirements(struct v3dv_buffer *buffer, .size = align64(buffer->size, buffer->alignment), }; + /* UBO and SSBO may be read using ldunifa, which prefetches the next + * 4 bytes after a read. If the buffer's size is exactly a multiple + * of a page size and the shader reads the last 4 bytes with ldunifa + * the prefetching would read out of bounds and cause an MMU error, + * so we allocate extra space to avoid kernel error spamming. + */ + bool can_ldunifa = buffer->usage & + (VK_BUFFER_USAGE_STORAGE_BUFFER_BIT | + VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT); + if (can_ldunifa && (buffer->size % 4096 == 0)) + pMemoryRequirements->memoryRequirements.size += buffer->alignment; + vk_foreach_struct(ext, pMemoryRequirements->pNext) { switch (ext->sType) { case VK_STRUCTURE_TYPE_MEMORY_DEDICATED_REQUIREMENTS: { diff --git a/src/gallium/drivers/v3d/v3d_resource.c b/src/gallium/drivers/v3d/v3d_resource.c index a0a210ccad5..d9a79614dd1 100644 --- a/src/gallium/drivers/v3d/v3d_resource.c +++ b/src/gallium/drivers/v3d/v3d_resource.c @@ -99,7 +99,17 @@ v3d_resource_bo_alloc(struct v3d_resource *rsc) struct pipe_screen *pscreen = prsc->screen; struct v3d_bo *bo; - bo = v3d_bo_alloc(v3d_screen(pscreen), rsc->size, "resource"); + /* Buffers may be read using ldunifa, which prefetches the next + * 4 bytes after a read. If the buffer's size is exactly a multiple + * of a page size and the shader reads the last 4 bytes with ldunifa + * the prefetching would read out of bounds and cause an MMU error, + * so we allocate extra space to avoid kernel error spamming. + */ + uint32_t size = rsc->size; + if (rsc->base.target == PIPE_BUFFER && (size % 4096 == 0)) + size += 4; + + bo = v3d_bo_alloc(v3d_screen(pscreen), size, "resource"); if (bo) { v3d_bo_unreference(&rsc->bo); rsc->bo = bo;
