cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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i915_gemfs.c (1387B)

      1/*
      2 * SPDX-License-Identifier: MIT
      3 *
      4 * Copyright © 2017 Intel Corporation
      5 */
      6
      7#include <linux/fs.h>
      8#include <linux/mount.h>
      9
     10#include "i915_drv.h"
     11#include "i915_gemfs.h"
     12#include "i915_utils.h"
     13
     14int i915_gemfs_init(struct drm_i915_private *i915)
     15{
     16	char huge_opt[] = "huge=within_size"; /* r/w */
     17	struct file_system_type *type;
     18	struct vfsmount *gemfs;
     19	char *opts;
     20
     21	type = get_fs_type("tmpfs");
     22	if (!type)
     23		return -ENODEV;
     24
     25	/*
     26	 * By creating our own shmemfs mountpoint, we can pass in
     27	 * mount flags that better match our usecase.
     28	 *
     29	 * One example, although it is probably better with a per-file
     30	 * control, is selecting huge page allocations ("huge=within_size").
     31	 * However, we only do so to offset the overhead of iommu lookups
     32	 * due to bandwidth issues (slow reads) on Broadwell+.
     33	 */
     34
     35	opts = NULL;
     36	if (i915_vtd_active(i915)) {
     37		if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
     38			opts = huge_opt;
     39			drm_info(&i915->drm,
     40				 "Transparent Hugepage mode '%s'\n",
     41				 opts);
     42		} else {
     43			drm_notice(&i915->drm,
     44				   "Transparent Hugepage support is recommended for optimal performance when IOMMU is enabled!\n");
     45		}
     46	}
     47
     48	gemfs = vfs_kern_mount(type, SB_KERNMOUNT, type->name, opts);
     49	if (IS_ERR(gemfs))
     50		return PTR_ERR(gemfs);
     51
     52	i915->mm.gemfs = gemfs;
     53
     54	return 0;
     55}
     56
     57void i915_gemfs_fini(struct drm_i915_private *i915)
     58{
     59	kern_unmount(i915->mm.gemfs);
     60}