diff options
Diffstat (limited to 'drivers/gpu/drm/i915/i915_vgpu.c')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_vgpu.c | 264 |
1 files changed, 264 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_vgpu.c b/drivers/gpu/drm/i915/i915_vgpu.c new file mode 100644 index 000000000000..5eee75bff170 --- /dev/null +++ b/drivers/gpu/drm/i915/i915_vgpu.c @@ -0,0 +1,264 @@ +/* + * Copyright(c) 2011-2015 Intel Corporation. All rights reserved. + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice (including the next + * paragraph) shall be included in all copies or substantial portions of the + * Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +#include "intel_drv.h" +#include "i915_vgpu.h" + +/** + * DOC: Intel GVT-g guest support + * + * Intel GVT-g is a graphics virtualization technology which shares the + * GPU among multiple virtual machines on a time-sharing basis. Each + * virtual machine is presented a virtual GPU (vGPU), which has equivalent + * features as the underlying physical GPU (pGPU), so i915 driver can run + * seamlessly in a virtual machine. This file provides vGPU specific + * optimizations when running in a virtual machine, to reduce the complexity + * of vGPU emulation and to improve the overall performance. + * + * A primary function introduced here is so-called "address space ballooning" + * technique. Intel GVT-g partitions global graphics memory among multiple VMs, + * so each VM can directly access a portion of the memory without hypervisor's + * intervention, e.g. filling textures or queuing commands. However with the + * partitioning an unmodified i915 driver would assume a smaller graphics + * memory starting from address ZERO, then requires vGPU emulation module to + * translate the graphics address between 'guest view' and 'host view', for + * all registers and command opcodes which contain a graphics memory address. + * To reduce the complexity, Intel GVT-g introduces "address space ballooning", + * by telling the exact partitioning knowledge to each guest i915 driver, which + * then reserves and prevents non-allocated portions from allocation. Thus vGPU + * emulation module only needs to scan and validate graphics addresses without + * complexity of address translation. + * + */ + +/** + * i915_check_vgpu - detect virtual GPU + * @dev: drm device * + * + * This function is called at the initialization stage, to detect whether + * running on a vGPU. + */ +void i915_check_vgpu(struct drm_device *dev) +{ + struct drm_i915_private *dev_priv = to_i915(dev); + uint64_t magic; + uint32_t version; + + BUILD_BUG_ON(sizeof(struct vgt_if) != VGT_PVINFO_SIZE); + + if (!IS_HASWELL(dev)) + return; + + magic = readq(dev_priv->regs + vgtif_reg(magic)); + if (magic != VGT_MAGIC) + return; + + version = INTEL_VGT_IF_VERSION_ENCODE( + readw(dev_priv->regs + vgtif_reg(version_major)), + readw(dev_priv->regs + vgtif_reg(version_minor))); + if (version != INTEL_VGT_IF_VERSION) { + DRM_INFO("VGT interface version mismatch!\n"); + return; + } + + dev_priv->vgpu.active = true; + DRM_INFO("Virtual GPU for Intel GVT-g detected.\n"); +} + +struct _balloon_info_ { + /* + * There are up to 2 regions per mappable/unmappable graphic + * memory that might be ballooned. Here, index 0/1 is for mappable + * graphic memory, 2/3 for unmappable graphic memory. + */ + struct drm_mm_node space[4]; +}; + +static struct _balloon_info_ bl_info; + +/** + * intel_vgt_deballoon - deballoon reserved graphics address trunks + * + * This function is called to deallocate the ballooned-out graphic memory, when + * driver is unloaded or when ballooning fails. + */ +void intel_vgt_deballoon(void) +{ + int i; + + DRM_DEBUG("VGT deballoon.\n"); + + for (i = 0; i < 4; i++) { + if (bl_info.space[i].allocated) + drm_mm_remove_node(&bl_info.space[i]); + } + + memset(&bl_info, 0, sizeof(bl_info)); +} + +static int vgt_balloon_space(struct drm_mm *mm, + struct drm_mm_node *node, + unsigned long start, unsigned long end) +{ + unsigned long size = end - start; + + if (start == end) + return -EINVAL; + + DRM_INFO("balloon space: range [ 0x%lx - 0x%lx ] %lu KiB.\n", + start, end, size / 1024); + + node->start = start; + node->size = size; + + return drm_mm_reserve_node(mm, node); +} + +/** + * intel_vgt_balloon - balloon out reserved graphics address trunks + * @dev: drm device + * + * This function is called at the initialization stage, to balloon out the + * graphic address space allocated to other vGPUs, by marking these spaces as + * reserved. The ballooning related knowledge(starting address and size of + * the mappable/unmappable graphic memory) is described in the vgt_if structure + * in a reserved mmio range. + * + * To give an example, the drawing below depicts one typical scenario after + * ballooning. Here the vGPU1 has 2 pieces of graphic address spaces ballooned + * out each for the mappable and the non-mappable part. From the vGPU1 point of + * view, the total size is the same as the physical one, with the start address + * of its graphic space being zero. Yet there are some portions ballooned out( + * the shadow part, which are marked as reserved by drm allocator). From the + * host point of view, the graphic address space is partitioned by multiple + * vGPUs in different VMs. + * + * vGPU1 view Host view + * 0 ------> +-----------+ +-----------+ + * ^ |///////////| | vGPU3 | + * | |///////////| +-----------+ + * | |///////////| | vGPU2 | + * | +-----------+ +-----------+ + * mappable GM | available | ==> | vGPU1 | + * | +-----------+ +-----------+ + * | |///////////| | | + * v |///////////| | Host | + * +=======+===========+ +===========+ + * ^ |///////////| | vGPU3 | + * | |///////////| +-----------+ + * | |///////////| | vGPU2 | + * | +-----------+ +-----------+ + * unmappable GM | available | ==> | vGPU1 | + * | +-----------+ +-----------+ + * | |///////////| | | + * | |///////////| | Host | + * v |///////////| | | + * total GM size ------> +-----------+ +-----------+ + * + * Returns: + * zero on success, non-zero if configuration invalid or ballooning failed + */ +int intel_vgt_balloon(struct drm_device *dev) +{ + struct drm_i915_private *dev_priv = to_i915(dev); + struct i915_address_space *ggtt_vm = &dev_priv->gtt.base; + unsigned long ggtt_vm_end = ggtt_vm->start + ggtt_vm->total; + + unsigned long mappable_base, mappable_size, mappable_end; + unsigned long unmappable_base, unmappable_size, unmappable_end; + int ret; + + mappable_base = I915_READ(vgtif_reg(avail_rs.mappable_gmadr.base)); + mappable_size = I915_READ(vgtif_reg(avail_rs.mappable_gmadr.size)); + unmappable_base = I915_READ(vgtif_reg(avail_rs.nonmappable_gmadr.base)); + unmappable_size = I915_READ(vgtif_reg(avail_rs.nonmappable_gmadr.size)); + + mappable_end = mappable_base + mappable_size; + unmappable_end = unmappable_base + unmappable_size; + + DRM_INFO("VGT ballooning configuration:\n"); + DRM_INFO("Mappable graphic memory: base 0x%lx size %ldKiB\n", + mappable_base, mappable_size / 1024); + DRM_INFO("Unmappable graphic memory: base 0x%lx size %ldKiB\n", + unmappable_base, unmappable_size / 1024); + + if (mappable_base < ggtt_vm->start || + mappable_end > dev_priv->gtt.mappable_end || + unmappable_base < dev_priv->gtt.mappable_end || + unmappable_end > ggtt_vm_end) { + DRM_ERROR("Invalid ballooning configuration!\n"); + return -EINVAL; + } + + /* Unmappable graphic memory ballooning */ + if (unmappable_base > dev_priv->gtt.mappable_end) { + ret = vgt_balloon_space(&ggtt_vm->mm, + &bl_info.space[2], + dev_priv->gtt.mappable_end, + unmappable_base); + + if (ret) + goto err; + } + + /* + * No need to partition out the last physical page, + * because it is reserved to the guard page. + */ + if (unmappable_end < ggtt_vm_end - PAGE_SIZE) { + ret = vgt_balloon_space(&ggtt_vm->mm, + &bl_info.space[3], + unmappable_end, + ggtt_vm_end - PAGE_SIZE); + if (ret) + goto err; + } + + /* Mappable graphic memory ballooning */ + if (mappable_base > ggtt_vm->start) { + ret = vgt_balloon_space(&ggtt_vm->mm, + &bl_info.space[0], + ggtt_vm->start, mappable_base); + + if (ret) + goto err; + } + + if (mappable_end < dev_priv->gtt.mappable_end) { + ret = vgt_balloon_space(&ggtt_vm->mm, + &bl_info.space[1], + mappable_end, + dev_priv->gtt.mappable_end); + + if (ret) + goto err; + } + + DRM_INFO("VGT balloon successfully\n"); + return 0; + +err: + DRM_ERROR("VGT balloon fail\n"); + intel_vgt_deballoon(); + return ret; +} |