/*
* 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");
}
