Commit 392bf222 authored by Ashutosh Dixit's avatar Ashutosh Dixit
Browse files

drm/xe/oa/uapi: OA buffer mmap 



Allow the OA buffer to be mmap'd to userspace. This is needed for the MMIO
trigger use case. Even otherwise, with whitelisted OA head/tail ptr
registers, userspace can receive/interpret OA data from the mmap'd buffer
without issuing read()'s on the OA stream fd.

v2: Remove unmap_mapping_range from xe_oa_release (Thomas H)
    Use vm_flags_mod (Umesh)

Acked-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
Suggested-by: default avatarUmesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Reviewed-by: default avatarUmesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Signed-off-by: default avatarAshutosh Dixit <ashutosh.dixit@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240618014609.3233427-14-ashutosh.dixit@intel.com
parent dd6b4718

drivers/gpu/drm/xe/xe_oa.c

+46 −0
Original line number Diff line number Diff line
@@ -824,6 +824,8 @@ static int xe_oa_alloc_oa_buffer(struct xe_oa_stream *stream) 
		return PTR_ERR(bo);



	stream->oa_buffer.bo = bo;

	/* mmap implementation requires OA buffer to be in system memory */

	xe_assert(stream->oa->xe, bo->vmap.is_iomem == 0);

	stream->oa_buffer.vaddr = bo->vmap.vaddr;

	return 0;

}
@@ -1125,6 +1127,49 @@ static int xe_oa_release(struct inode *inode, struct file *file) 
	return 0;

}



static int xe_oa_mmap(struct file *file, struct vm_area_struct *vma)

{

	struct xe_oa_stream *stream = file->private_data;

	struct xe_bo *bo = stream->oa_buffer.bo;

	unsigned long start = vma->vm_start;

	int i, ret;



	if (xe_perf_stream_paranoid && !perfmon_capable()) {

		drm_dbg(&stream->oa->xe->drm, "Insufficient privilege to map OA buffer\n");

		return -EACCES;

	}



	/* Can mmap the entire OA buffer or nothing (no partial OA buffer mmaps) */

	if (vma->vm_end - vma->vm_start != XE_OA_BUFFER_SIZE) {

		drm_dbg(&stream->oa->xe->drm, "Wrong mmap size, must be OA buffer size\n");

		return -EINVAL;

	}



	/*

	 * Only support VM_READ, enforce MAP_PRIVATE by checking for

	 * VM_MAYSHARE, don't copy the vma on fork

	 */

	if (vma->vm_flags & (VM_WRITE | VM_EXEC | VM_SHARED | VM_MAYSHARE)) {

		drm_dbg(&stream->oa->xe->drm, "mmap must be read only\n");

		return -EINVAL;

	}

	vm_flags_mod(vma, VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP | VM_DONTCOPY,

		     VM_MAYWRITE | VM_MAYEXEC);



	xe_assert(stream->oa->xe, bo->ttm.ttm->num_pages ==

		  (vma->vm_end - vma->vm_start) >> PAGE_SHIFT);

	for (i = 0; i < bo->ttm.ttm->num_pages; i++) {

		ret = remap_pfn_range(vma, start, page_to_pfn(bo->ttm.ttm->pages[i]),

				      PAGE_SIZE, vma->vm_page_prot);

		if (ret)

			break;



		start += PAGE_SIZE;

	}



	return ret;

}



static const struct file_operations xe_oa_fops = {

	.owner		= THIS_MODULE,

	.llseek		= no_llseek,
@@ -1132,6 +1177,7 @@ static const struct file_operations xe_oa_fops = { 
	.poll		= xe_oa_poll,

	.read		= xe_oa_read,

	.unlocked_ioctl	= xe_oa_ioctl,

	.mmap		= xe_oa_mmap,

};



static bool engine_supports_mi_query(struct xe_hw_engine *hwe)