drivers/gpu/drm/i915/i915_vgpu.c

   1 /*
   2  * Copyright(c) 2011-2015 Intel Corporation. All rights reserved.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  20  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  21  * SOFTWARE.
  22  */
  23
  24 #include "intel_drv.h"
  25 #include "i915_vgpu.h"
  26
  27 /**
  28  * DOC: Intel GVT-g guest support
  29  *
  30  * Intel GVT-g is a graphics virtualization technology which shares the
  31  * GPU among multiple virtual machines on a time-sharing basis. Each
  32  * virtual machine is presented a virtual GPU (vGPU), which has equivalent
  33  * features as the underlying physical GPU (pGPU), so i915 driver can run
  34  * seamlessly in a virtual machine. This file provides vGPU specific
  35  * optimizations when running in a virtual machine, to reduce the complexity
  36  * of vGPU emulation and to improve the overall performance.
  37  *
  38  * A primary function introduced here is so-called "address space ballooning"
  39  * technique. Intel GVT-g partitions global graphics memory among multiple VMs,
  40  * so each VM can directly access a portion of the memory without hypervisor's
  41  * intervention, e.g. filling textures or queuing commands. However with the
  42  * partitioning an unmodified i915 driver would assume a smaller graphics
  43  * memory starting from address ZERO, then requires vGPU emulation module to
  44  * translate the graphics address between 'guest view' and 'host view', for
  45  * all registers and command opcodes which contain a graphics memory address.
  46  * To reduce the complexity, Intel GVT-g introduces "address space ballooning",
  47  * by telling the exact partitioning knowledge to each guest i915 driver, which
  48  * then reserves and prevents non-allocated portions from allocation. Thus vGPU
  49  * emulation module only needs to scan and validate graphics addresses without
  50  * complexity of address translation.
  51  *
  52  */
  53
  54 /**
  55  * i915_check_vgpu - detect virtual GPU
  56  * @dev_priv: i915 device private
  57  *
  58  * This function is called at the initialization stage, to detect whether
  59  * running on a vGPU.
  60  */
  61 void i915_check_vgpu(struct drm_i915_private *dev_priv)
  62 {
  63         u64 magic;
  64         u16 version_major;
  65
  66         BUILD_BUG_ON(sizeof(struct vgt_if) != VGT_PVINFO_SIZE);
  67
  68         magic = __raw_i915_read64(dev_priv, vgtif_reg(magic));
  69         if (magic != VGT_MAGIC)
  70                 return;
  71
  72         version_major = __raw_i915_read16(dev_priv, vgtif_reg(version_major));
  73         if (version_major < VGT_VERSION_MAJOR) {
  74                 DRM_INFO("VGT interface version mismatch!\n");
  75                 return;
  76         }
  77
  78         dev_priv->vgpu.caps = __raw_i915_read32(dev_priv, vgtif_reg(vgt_caps));
  79
  80         dev_priv->vgpu.active = true;
  81         DRM_INFO("Virtual GPU for Intel GVT-g detected.\n");
  82 }
  83
  84 bool intel_vgpu_has_full_48bit_ppgtt(struct drm_i915_private *dev_priv)
  85 {
  86         return dev_priv->vgpu.caps & VGT_CAPS_FULL_48BIT_PPGTT;
  87 }
  88
  89 struct _balloon_info_ {
  90         /*
  91          * There are up to 2 regions per mappable/unmappable graphic
  92          * memory that might be ballooned. Here, index 0/1 is for mappable
  93          * graphic memory, 2/3 for unmappable graphic memory.
  94          */
  95         struct drm_mm_node space[4];
  96 };
  97
  98 static struct _balloon_info_ bl_info;
  99
 100 static void vgt_deballoon_space(struct i915_ggtt *ggtt,
 101                                 struct drm_mm_node *node)
 102 {
 103         if (!drm_mm_node_allocated(node))
 104                 return;
 105
 106         DRM_DEBUG_DRIVER("deballoon space: range [0x%llx - 0x%llx] %llu KiB.\n",
 107                          node->start,
 108                          node->start + node->size,
 109                          node->size / 1024);
 110
 111         ggtt->vm.reserved -= node->size;
 112         drm_mm_remove_node(node);
 113 }
 114
 115 /**
 116  * intel_vgt_deballoon - deballoon reserved graphics address trunks
 117  * @dev_priv: i915 device private data
 118  *
 119  * This function is called to deallocate the ballooned-out graphic memory, when
 120  * driver is unloaded or when ballooning fails.
 121  */
 122 void intel_vgt_deballoon(struct drm_i915_private *dev_priv)
 123 {
 124         int i;
 125
 126         if (!intel_vgpu_active(dev_priv))
 127                 return;
 128
 129         DRM_DEBUG("VGT deballoon.\n");
 130
 131         for (i = 0; i < 4; i++)
 132                 vgt_deballoon_space(&dev_priv->ggtt, &bl_info.space[i]);
 133 }
 134
 135 static int vgt_balloon_space(struct i915_ggtt *ggtt,
 136                              struct drm_mm_node *node,
 137                              unsigned long start, unsigned long end)
 138 {
 139         unsigned long size = end - start;
 140         int ret;
 141
 142         if (start >= end)
 143                 return -EINVAL;
 144
 145         DRM_INFO("balloon space: range [ 0x%lx - 0x%lx ] %lu KiB.\n",
 146                  start, end, size / 1024);
 147         ret = i915_gem_gtt_reserve(&ggtt->vm, node,
 148                                    size, start, I915_COLOR_UNEVICTABLE,
 149                                    0);
 150         if (!ret)
 151                 ggtt->vm.reserved += size;
 152
 153         return ret;
 154 }
 155
 156 /**
 157  * intel_vgt_balloon - balloon out reserved graphics address trunks
 158  * @dev_priv: i915 device private data
 159  *
 160  * This function is called at the initialization stage, to balloon out the
 161  * graphic address space allocated to other vGPUs, by marking these spaces as
 162  * reserved. The ballooning related knowledge(starting address and size of
 163  * the mappable/unmappable graphic memory) is described in the vgt_if structure
 164  * in a reserved mmio range.
 165  *
 166  * To give an example, the drawing below depicts one typical scenario after
 167  * ballooning. Here the vGPU1 has 2 pieces of graphic address spaces ballooned
 168  * out each for the mappable and the non-mappable part. From the vGPU1 point of
 169  * view, the total size is the same as the physical one, with the start address
 170  * of its graphic space being zero. Yet there are some portions ballooned out(
 171  * the shadow part, which are marked as reserved by drm allocator). From the
 172  * host point of view, the graphic address space is partitioned by multiple
 173  * vGPUs in different VMs. ::
 174  *
 175  *                         vGPU1 view         Host view
 176  *              0 ------> +-----------+     +-----------+
 177  *                ^       |###########|     |   vGPU3   |
 178  *                |       |###########|     +-----------+
 179  *                |       |###########|     |   vGPU2   |
 180  *                |       +-----------+     +-----------+
 181  *         mappable GM    | available | ==> |   vGPU1   |
 182  *                |       +-----------+     +-----------+
 183  *                |       |###########|     |           |
 184  *                v       |###########|     |   Host    |
 185  *                +=======+===========+     +===========+
 186  *                ^       |###########|     |   vGPU3   |
 187  *                |       |###########|     +-----------+
 188  *                |       |###########|     |   vGPU2   |
 189  *                |       +-----------+     +-----------+
 190  *       unmappable GM    | available | ==> |   vGPU1   |
 191  *                |       +-----------+     +-----------+
 192  *                |       |###########|     |           |
 193  *                |       |###########|     |   Host    |
 194  *                v       |###########|     |           |
 195  *  total GM size ------> +-----------+     +-----------+
 196  *
 197  * Returns:
 198  * zero on success, non-zero if configuration invalid or ballooning failed
 199  */
 200 int intel_vgt_balloon(struct drm_i915_private *dev_priv)
 201 {
 202         struct i915_ggtt *ggtt = &dev_priv->ggtt;
 203         unsigned long ggtt_end = ggtt->vm.total;
 204
 205         unsigned long mappable_base, mappable_size, mappable_end;
 206         unsigned long unmappable_base, unmappable_size, unmappable_end;
 207         int ret;
 208
 209         if (!intel_vgpu_active(dev_priv))
 210                 return 0;
 211
 212         mappable_base = I915_READ(vgtif_reg(avail_rs.mappable_gmadr.base));
 213         mappable_size = I915_READ(vgtif_reg(avail_rs.mappable_gmadr.size));
 214         unmappable_base = I915_READ(vgtif_reg(avail_rs.nonmappable_gmadr.base));
 215         unmappable_size = I915_READ(vgtif_reg(avail_rs.nonmappable_gmadr.size));
 216
 217         mappable_end = mappable_base + mappable_size;
 218         unmappable_end = unmappable_base + unmappable_size;
 219
 220         DRM_INFO("VGT ballooning configuration:\n");
 221         DRM_INFO("Mappable graphic memory: base 0x%lx size %ldKiB\n",
 222                  mappable_base, mappable_size / 1024);
 223         DRM_INFO("Unmappable graphic memory: base 0x%lx size %ldKiB\n",
 224                  unmappable_base, unmappable_size / 1024);
 225
 226         if (mappable_end > ggtt->mappable_end ||
 227             unmappable_base < ggtt->mappable_end ||
 228             unmappable_end > ggtt_end) {
 229                 DRM_ERROR("Invalid ballooning configuration!\n");
 230                 return -EINVAL;
 231         }
 232
 233         /* Unmappable graphic memory ballooning */
 234         if (unmappable_base > ggtt->mappable_end) {
 235                 ret = vgt_balloon_space(ggtt, &bl_info.space[2],
 236                                         ggtt->mappable_end, unmappable_base);
 237
 238                 if (ret)
 239                         goto err;
 240         }
 241
 242         if (unmappable_end < ggtt_end) {
 243                 ret = vgt_balloon_space(ggtt, &bl_info.space[3],
 244                                         unmappable_end, ggtt_end);
 245                 if (ret)
 246                         goto err_upon_mappable;
 247         }
 248
 249         /* Mappable graphic memory ballooning */
 250         if (mappable_base) {
 251                 ret = vgt_balloon_space(ggtt, &bl_info.space[0],
 252                                         0, mappable_base);
 253
 254                 if (ret)
 255                         goto err_upon_unmappable;
 256         }
 257
 258         if (mappable_end < ggtt->mappable_end) {
 259                 ret = vgt_balloon_space(ggtt, &bl_info.space[1],
 260                                         mappable_end, ggtt->mappable_end);
 261
 262                 if (ret)
 263                         goto err_below_mappable;
 264         }
 265
 266         DRM_INFO("VGT balloon successfully\n");
 267         return 0;
 268
 269 err_below_mappable:
 270         vgt_deballoon_space(ggtt, &bl_info.space[0]);
 271 err_upon_unmappable:
 272         vgt_deballoon_space(ggtt, &bl_info.space[3]);
 273 err_upon_mappable:
 274         vgt_deballoon_space(ggtt, &bl_info.space[2]);
 275 err:
 276         DRM_ERROR("VGT balloon fail\n");
 277         return ret;
 278 }