drm/i915/gvt: Save/restore HW status to support GVT suspend/resume

This patch save/restore necessary GVT info during i915 suspend/resume so
that GVT enabled QEMU VM can continue running.

Only GGTT and fence regs are saved/restored now. GVT will save GGTT
entries on each host_entry update, restore the saved dirty entries
and re-init fence regs in resume routine.

V2:
- Change kzalloc/kfree to vzalloc/vfree since the space allocated
from kmalloc may not enough for all saved GGTT entries.
- Keep gvt suspend/resume wrapper in intel_gvt.h/intel_gvt.c and
move the actual implementation to gvt.h/gvt.c. (zhenyu)
- Check gvt config on and active with intel_gvt_active(). (zhenyu)

V3: (zhenyu)
- Incorrect copy length. Should be num entries * entry size.
- Use memcpy_toio()/memcpy_fromio() instead of memcpy for iomem.
- Add F_PM_SAVE flags to indicate which MMIOs to save/restore for PM.

V4:
Rebase.

V5:
Fail intel_gvt_save_ggtt as -ENOMEM if fail to alloc memory to save
ggtt. Free allocated ggtt_entries on failure.

V6:
Save host entry to per-vGPU gtt.ggtt_mm on each host_entry update.

V7:
Restore GGTT entry based on present bit.
Split fence restore and mmio restore in different functions.

Reviewed-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Hang Yuan <hang.yuan@linux.intel.com>
Signed-off-by: Colin Xu <colin.xu@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20201027045308.158955-1-colin.xu@intel.com

1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_gvt.c b/drivers/gpu/drm/i915/intel_gvt.c
index 99fe8aef1c67..4e70c1a9ef2e 100644
--- a/drivers/gpu/drm/i915/intel_gvt.c
+++ b/drivers/gpu/drm/i915/intel_gvt.c
@@ -24,6 +24,7 @@
 #include "i915_drv.h"
 #include "i915_vgpu.h"
 #include "intel_gvt.h"
+#include "gvt/gvt.h"
 
 /**
  * DOC: Intel GVT-g host support
@@ -147,3 +148,17 @@ void intel_gvt_driver_remove(struct drm_i915_private *dev_priv)
 
 	intel_gvt_clean_device(dev_priv);
 }
+
+/**
+ * intel_gvt_resume - GVT resume routine wapper
+ *
+ * @dev_priv: drm i915 private *
+ *
+ * This function is called at the i915 driver resume stage to restore required
+ * HW status for GVT so that vGPU can continue running after resumed.
+ */
+void intel_gvt_resume(struct drm_i915_private *dev_priv)
+{
+	if (intel_gvt_active(dev_priv))
+		intel_gvt_pm_resume(dev_priv->gvt);
+}