[PATCH v7 2/3] i915/gvt: Save the initial HW state snapshot in i915

Zhi Wang
2022-03-25T19:28:25Z

Save the initial HW state snapshot in i915 so that the rest code of GVT-g
can be moved into a dedicated module while it can still get a clean
initial HW state saved at the correct time during the initialization of
i915. The futhrer vGPU created by GVT-g will use this HW state as the
initial HW state.

v6:

- Remove the reference of intel_gvt_device_info.(Christoph)
- Refine the save_mmio() function. (Christoph)

Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Vivi Rodrigo <rodrigo.vivi@intel.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>
---
drivers/gpu/drm/i915/i915_drv.h | 2 +
drivers/gpu/drm/i915/intel_gvt.c | 92 +++++++++++++++++++++++++++++++-
2 files changed, 92 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 418091484e02..0edc9ecbd403 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -429,6 +429,8 @@ struct i915_virtual_gpu {
struct mutex lock; /* serialises sending of g2v_notify command pkts */
bool active;
u32 caps;
+ u32 *initial_mmio;
+ u8 *initial_cfg_space;
};

struct i915_selftest_stash {
diff --git a/drivers/gpu/drm/i915/intel_gvt.c b/drivers/gpu/drm/i915/intel_gvt.c
index cf6e98962d82..65daab2c4d9e 100644
--- a/drivers/gpu/drm/i915/intel_gvt.c
+++ b/drivers/gpu/drm/i915/intel_gvt.c
@@ -86,6 +86,85 @@ void intel_gvt_sanitize_options(struct drm_i915_private *dev_priv)
dev_priv->params.enable_gvt = 0;
}

+static void free_initial_hw_state(struct drm_i915_private *dev_priv)
+{
+ struct i915_virtual_gpu *vgpu = &dev_priv->vgpu;
+
+ vfree(vgpu->initial_mmio);
+ vgpu->initial_mmio = NULL;
+
+ kfree(vgpu->initial_cfg_space);
+ vgpu->initial_cfg_space = NULL;
+}
+
+static void save_mmio(struct intel_gvt_mmio_table_iter *iter, u32 offset,
+ u32 size)
+{
+ struct drm_i915_private *dev_priv = iter->i915;
+ u32 *mmio, i;
+
+ for (i = offset; i < offset + size; i += 4) {
+ mmio = iter->data + i;
+ *mmio = intel_uncore_read_notrace(to_gt(dev_priv)->uncore,
+ _MMIO(i));
+ }
+}
+
+static int handle_mmio(struct intel_gvt_mmio_table_iter *iter,
+ u32 offset, u32 size)
+{
+ if (WARN_ON(!IS_ALIGNED(offset, 4)))
+ return -EINVAL;
+
+ save_mmio(iter, offset, size);
+ return 0;
+}
+
+static int save_initial_hw_state(struct drm_i915_private *dev_priv)
+{
+ struct pci_dev *pdev = to_pci_dev(dev_priv->drm.dev);
+ struct i915_virtual_gpu *vgpu = &dev_priv->vgpu;
+ struct intel_gvt_mmio_table_iter iter;
+ void *mem;
+ int i, ret;
+
+ mem = kzalloc(PCI_CFG_SPACE_EXP_SIZE, GFP_KERNEL);
+ if (!mem)
+ return -ENOMEM;
+
+ vgpu->initial_cfg_space = mem;
+
+ for (i = 0; i < PCI_CFG_SPACE_EXP_SIZE; i += 4)
+ pci_read_config_dword(pdev, i, mem + i);
+
+ mem = vzalloc(2 * SZ_1M);
+ if (!mem) {
+ ret = -ENOMEM;
+ goto err_mmio;
+ }
+
+ vgpu->initial_mmio = mem;
+
+ iter.i915 = dev_priv;
+ iter.data = vgpu->initial_mmio;
+ iter.handle_mmio_cb = handle_mmio;
+
+ ret = intel_gvt_iterate_mmio_table(&iter);
+ if (ret)
+ goto err_iterate;
+
+ return 0;
+
+err_iterate:
+ vfree(vgpu->initial_mmio);
+ vgpu->initial_mmio = NULL;
+err_mmio:
+ kfree(vgpu->initial_cfg_space);
+ vgpu->initial_cfg_space = NULL;
+
+ return ret;
+}
+
/**
* intel_gvt_init - initialize GVT components
* @dev_priv: drm i915 private data
@@ -115,15 +194,23 @@ int intel_gvt_init(struct drm_i915_private *dev_priv)
return -EIO;
}

+ ret = save_initial_hw_state(dev_priv);
+ if (ret) {
+ drm_dbg(&dev_priv->drm, "Fail to save initial HW state\n");
+ goto err_save_hw_state;
+ }
+
ret = intel_gvt_init_device(dev_priv);
if (ret) {
drm_dbg(&dev_priv->drm, "Fail to init GVT device\n");
- goto bail;
+ goto err_init_device;
}

return 0;

-bail:
+err_init_device:
+ free_initial_hw_state(dev_priv);
+err_save_hw_state:
dev_priv->params.enable_gvt = 0;
return 0;
}
@@ -147,6 +234,7 @@ void intel_gvt_driver_remove(struct drm_i915_private *dev_priv)
return;

intel_gvt_clean_device(dev_priv);
+ free_initial_hw_state(dev_priv);
}

/**
--
2.25.1