Commit dff547e1 authored by Thomas Hellström's avatar Thomas Hellström
Browse files

drm/xe/uapi: Extend the madvise functionality to support foreign pagemap placement for svm 



Use device file descriptors and regions to represent pagemaps on
foreign or local devices.

The underlying files are type-checked at madvise time, and
references are kept on the drm_pagemap as long as there is are
madvises pointing to it.

Extend the madvise preferred_location UAPI to support the region
instance to identify the foreign placement.

v2:
- Improve UAPI documentation. (Matt Brost)
- Sanitize preferred_mem_loc.region_instance madvise. (Matt Brost)
- Clarify madvise drm_pagemap vs xe_pagemap refcounting. (Matt Brost)
- Don't allow a foreign drm_pagemap madvise without a fast
  interconnect.
v3:
- Add a comment about reference-counting in xe_devmem_open() and
  remove the reference-count get-and-put. (Matt Brost)

Signed-off-by: default avatarThomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: default avatarMatthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20251219113320.183860-16-thomas.hellstrom@linux.intel.com
parent 4be5f2bc

drivers/gpu/drm/xe/xe_device.c

+14 −0
Original line number Diff line number Diff line
@@ -378,6 +378,20 @@ static const struct file_operations xe_driver_fops = { 
	.fop_flags = FOP_UNSIGNED_OFFSET,

};



/**

 * xe_is_xe_file() - Is the file an xe device file?

 * @file: The file.

 *

 * Checks whether the file is opened against

 * an xe device.

 *

 * Return: %true if an xe file, %false if not.

 */

bool xe_is_xe_file(const struct file *file)

{

	return file->f_op == &xe_driver_fops;

}



static struct drm_driver driver = {

	/* Don't use MTRRs here; the Xserver or userspace app should

	 * deal with them for Intel hardware.

drivers/gpu/drm/xe/xe_device.h

+2 −0
Original line number Diff line number Diff line
@@ -200,6 +200,8 @@ void xe_file_put(struct xe_file *xef); 


int xe_is_injection_active(void);



bool xe_is_xe_file(const struct file *file);



/*

 * Occasionally it is seen that the G2H worker starts running after a delay of more than

 * a second even after being queued and activated by the Linux workqueue subsystem. This

drivers/gpu/drm/xe/xe_svm.c

+75 −0
Original line number Diff line number Diff line
@@ -1813,6 +1813,75 @@ int xe_pagemap_cache_create(struct xe_tile *tile) 
	return 0;

}



static struct drm_pagemap *xe_devmem_open(struct xe_device *xe, u32 region_instance)

{

	u32 tile_id = region_instance - 1;

	struct xe_pagemap *xpagemap;

	struct xe_vram_region *vr;



	if (tile_id >= xe->info.tile_count)

		return ERR_PTR(-ENOENT);



	if (!((BIT(tile_id) << 1) & xe->info.mem_region_mask))

		return ERR_PTR(-ENOENT);



	vr = xe_tile_to_vr(&xe->tiles[tile_id]);



	/* Returns a reference-counted embedded struct drm_pagemap */

	xpagemap = xe_pagemap_find_or_create(xe, vr->dpagemap_cache, vr);

	if (IS_ERR(xpagemap))

		return ERR_CAST(xpagemap);



	return &xpagemap->dpagemap;

}



/**

 * xe_drm_pagemap_from_fd() - Return a drm_pagemap pointer from a

 * (file_descriptor, region_instance) pair.

 * @fd: An fd opened against an xe device.

 * @region_instance: The region instance representing the device memory

 * on the opened xe device.

 *

 * Opens a struct drm_pagemap pointer on the

 * indicated device and region_instance.

 *

 * Return: A reference-counted struct drm_pagemap pointer on success,

 * negative error pointer on failure.

 */

struct drm_pagemap *xe_drm_pagemap_from_fd(int fd, u32 region_instance)

{

	struct drm_pagemap *dpagemap;

	struct file *file;

	struct drm_file *fpriv;

	struct drm_device *drm;

	int idx;



	if (fd <= 0)

		return ERR_PTR(-EINVAL);



	file = fget(fd);

	if (!file)

		return ERR_PTR(-ENOENT);



	if (!xe_is_xe_file(file)) {

		dpagemap = ERR_PTR(-ENOENT);

		goto out;

	}



	fpriv = file->private_data;

	drm = fpriv->minor->dev;

	if (!drm_dev_enter(drm, &idx)) {

		dpagemap = ERR_PTR(-ENODEV);

		goto out;

	}



	dpagemap = xe_devmem_open(to_xe_device(drm), region_instance);

	drm_dev_exit(idx);

out:

	fput(file);

	return dpagemap;

}



#else



int xe_pagemap_shrinker_create(struct xe_device *xe)
@@ -1836,6 +1905,12 @@ struct drm_pagemap *xe_vma_resolve_pagemap(struct xe_vma *vma, struct xe_tile *t 
{

	return NULL;

}



struct drm_pagemap *xe_drm_pagemap_from_fd(int fd, u32 region_instance)

{

	return ERR_PTR(-ENOENT);

}



#endif



/**

drivers/gpu/drm/xe/xe_svm.h

+7 −0
Original line number Diff line number Diff line
@@ -187,6 +187,8 @@ int xe_pagemap_shrinker_create(struct xe_device *xe); 


int xe_pagemap_cache_create(struct xe_tile *tile);



struct drm_pagemap *xe_drm_pagemap_from_fd(int fd, u32 region_instance);



#else

#include <linux/interval_tree.h>

#include "xe_vm.h"
@@ -378,6 +380,11 @@ static inline int xe_pagemap_cache_create(struct xe_tile *tile) 
	return 0;

}



static inline struct drm_pagemap *xe_drm_pagemap_from_fd(int fd, u32 region_instance)

{

	return ERR_PTR(-ENOENT);

}



#define xe_svm_range_has_dma_mapping(...) false

#endif /* CONFIG_DRM_XE_GPUSVM */

drivers/gpu/drm/xe/xe_vm_madvise.c

+75 −11
Original line number Diff line number Diff line
@@ -22,6 +22,19 @@ struct xe_vmas_in_madvise_range { 
	bool has_svm_userptr_vmas;

};



/**

 * struct xe_madvise_details - Argument to madvise_funcs

 * @dpagemap: Reference-counted pointer to a struct drm_pagemap.

 *

 * The madvise IOCTL handler may, in addition to the user-space

 * args, have additional info to pass into the madvise_func that

 * handles the madvise type. Use a struct_xe_madvise_details

 * for that and extend the struct as necessary.

 */

struct xe_madvise_details {

	struct drm_pagemap *dpagemap;

};



static int get_vmas(struct xe_vm *vm, struct xe_vmas_in_madvise_range *madvise_range)

{

	u64 addr = madvise_range->addr;
@@ -74,7 +87,8 @@ static int get_vmas(struct xe_vm *vm, struct xe_vmas_in_madvise_range *madvise_r 


static void madvise_preferred_mem_loc(struct xe_device *xe, struct xe_vm *vm,

				      struct xe_vma **vmas, int num_vmas,

				      struct drm_xe_madvise *op)

				      struct drm_xe_madvise *op,

				      struct xe_madvise_details *details)

{

	int i;
@@ -96,14 +110,18 @@ static void madvise_preferred_mem_loc(struct xe_device *xe, struct xe_vm *vm, 
			 * is of no use and can be ignored.

			 */

			loc->migration_policy = op->preferred_mem_loc.migration_policy;

			drm_pagemap_put(loc->dpagemap);

			loc->dpagemap = NULL;

			if (details->dpagemap)

				loc->dpagemap = drm_pagemap_get(details->dpagemap);

		}

	}

}



static void madvise_atomic(struct xe_device *xe, struct xe_vm *vm,

			   struct xe_vma **vmas, int num_vmas,

			   struct drm_xe_madvise *op)

			   struct drm_xe_madvise *op,

			   struct xe_madvise_details *details)

{

	struct xe_bo *bo;

	int i;
@@ -144,7 +162,8 @@ static void madvise_atomic(struct xe_device *xe, struct xe_vm *vm, 


static void madvise_pat_index(struct xe_device *xe, struct xe_vm *vm,

			      struct xe_vma **vmas, int num_vmas,

			      struct drm_xe_madvise *op)

			      struct drm_xe_madvise *op,

			      struct xe_madvise_details *details)

{

	int i;
@@ -162,7 +181,8 @@ static void madvise_pat_index(struct xe_device *xe, struct xe_vm *vm, 


typedef void (*madvise_func)(struct xe_device *xe, struct xe_vm *vm,

			     struct xe_vma **vmas, int num_vmas,

			     struct drm_xe_madvise *op);

			     struct drm_xe_madvise *op,

			     struct xe_madvise_details *details);



static const madvise_func madvise_funcs[] = {

	[DRM_XE_MEM_RANGE_ATTR_PREFERRED_LOC] = madvise_preferred_mem_loc,
@@ -246,11 +266,12 @@ static bool madvise_args_are_sane(struct xe_device *xe, const struct drm_xe_madv 
		if (XE_IOCTL_DBG(xe, fd < DRM_XE_PREFERRED_LOC_DEFAULT_SYSTEM))

			return false;



		if (XE_IOCTL_DBG(xe, args->preferred_mem_loc.migration_policy >

				     DRM_XE_MIGRATE_ONLY_SYSTEM_PAGES))

		if (XE_IOCTL_DBG(xe, fd <= DRM_XE_PREFERRED_LOC_DEFAULT_DEVICE &&

				 args->preferred_mem_loc.region_instance != 0))

			return false;



		if (XE_IOCTL_DBG(xe, args->preferred_mem_loc.pad))

		if (XE_IOCTL_DBG(xe, args->preferred_mem_loc.migration_policy >

				     DRM_XE_MIGRATE_ONLY_SYSTEM_PAGES))

			return false;



		if (XE_IOCTL_DBG(xe, args->preferred_mem_loc.reserved))
@@ -296,6 +317,41 @@ static bool madvise_args_are_sane(struct xe_device *xe, const struct drm_xe_madv 
	return true;

}



static int xe_madvise_details_init(struct xe_vm *vm, const struct drm_xe_madvise *args,

				   struct xe_madvise_details *details)

{

	struct xe_device *xe = vm->xe;



	memset(details, 0, sizeof(*details));



	if (args->type == DRM_XE_MEM_RANGE_ATTR_PREFERRED_LOC) {

		int fd = args->preferred_mem_loc.devmem_fd;

		struct drm_pagemap *dpagemap;



		if (fd <= 0)

			return 0;



		dpagemap = xe_drm_pagemap_from_fd(args->preferred_mem_loc.devmem_fd,

						  args->preferred_mem_loc.region_instance);

		if (XE_IOCTL_DBG(xe, IS_ERR(dpagemap)))

			return PTR_ERR(dpagemap);



		/* Don't allow a foreign placement without a fast interconnect! */

		if (XE_IOCTL_DBG(xe, dpagemap->pagemap->owner != vm->svm.peer.owner)) {

			drm_pagemap_put(dpagemap);

			return -ENOLINK;

		}

		details->dpagemap = dpagemap;

	}



	return 0;

}



static void xe_madvise_details_fini(struct xe_madvise_details *details)

{

	drm_pagemap_put(details->dpagemap);

}



static bool check_bo_args_are_sane(struct xe_vm *vm, struct xe_vma **vmas,

				   int num_vmas, u32 atomic_val)

{
@@ -349,6 +405,7 @@ int xe_vm_madvise_ioctl(struct drm_device *dev, void *data, struct drm_file *fil 
	struct drm_xe_madvise *args = data;

	struct xe_vmas_in_madvise_range madvise_range = {.addr = args->start,

							 .range =  args->range, };

	struct xe_madvise_details details;

	struct xe_vm *vm;

	struct drm_exec exec;

	int err, attr_type;
@@ -373,13 +430,17 @@ int xe_vm_madvise_ioctl(struct drm_device *dev, void *data, struct drm_file *fil 
		goto unlock_vm;

	}



	err = xe_vm_alloc_madvise_vma(vm, args->start, args->range);

	err = xe_madvise_details_init(vm, args, &details);

	if (err)

		goto unlock_vm;



	err = xe_vm_alloc_madvise_vma(vm, args->start, args->range);

	if (err)

		goto madv_fini;



	err = get_vmas(vm, &madvise_range);

	if (err || !madvise_range.num_vmas)

		goto unlock_vm;

		goto madv_fini;



	if (madvise_range.has_bo_vmas) {

		if (args->type == DRM_XE_MEM_RANGE_ATTR_ATOMIC) {
@@ -387,7 +448,7 @@ int xe_vm_madvise_ioctl(struct drm_device *dev, void *data, struct drm_file *fil 
						    madvise_range.num_vmas,

						    args->atomic.val)) {

				err = -EINVAL;

				goto unlock_vm;

				goto madv_fini;

			}

		}
@@ -413,7 +474,8 @@ int xe_vm_madvise_ioctl(struct drm_device *dev, void *data, struct drm_file *fil 
	}



	attr_type = array_index_nospec(args->type, ARRAY_SIZE(madvise_funcs));

	madvise_funcs[attr_type](xe, vm, madvise_range.vmas, madvise_range.num_vmas, args);

	madvise_funcs[attr_type](xe, vm, madvise_range.vmas, madvise_range.num_vmas, args,

				 &details);



	err = xe_vm_invalidate_madvise_range(vm, args->start, args->start + args->range);
@@ -425,6 +487,8 @@ int xe_vm_madvise_ioctl(struct drm_device *dev, void *data, struct drm_file *fil 
		drm_exec_fini(&exec);

	kfree(madvise_range.vmas);

	madvise_range.vmas = NULL;

madv_fini:

	xe_madvise_details_fini(&details);

unlock_vm:

	up_write(&vm->lock);

put_vm: