drm/i915/gvt: Do not destroy ppgtt_mm during vGPU D3->D0.

When system enters S3 state, device enters D3 state while RAM remains
powered. From vGPU/GVT perspective, ppgtt_mm is residual in guest memory
during vGPU in D3 state, so that when guest state transits from S3->S0,
ppgtt_mm can be re-used and no need rebuild.

Previous implementation invalidate and destroy ppgtt_mm at DMLR,
regardless the power state transition is S0->S3->S0 (guest suspend or
resume) or OFF->S0 (normal boot/reboot), invalidate and destroy ppgtt_mm
is unnecessary in the former transition case.

The patch saves the vGPU D3/D0 transition state when guest writes the
PCI_PM_CTRL in vGPU's configure space, then in later DMLR, GVT can decide
whether or not invalidate and destroy ppgtt_mm is required. The
d3_entered flags is reset after DMLR.

To test this feature, make sure S3 is enabled in QEMU parameters:
i440fx: PIIX4_PM.disable_s3=0
q35: ICH9-LPC.disable_s3=0
Also need enable sleep option in guest OS if it's disabled.

v2:
- Revise commit message to more accurate description. (Kevin)
- Split patch by logic. (Zhenyu)

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/20200709071002.247960-2-colin.xu@intel.com

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
index 210016192ce7..a3a4305eda01 100644
--- a/drivers/gpu/drm/i915/gvt/gtt.c
+++ b/drivers/gpu/drm/i915/gvt/gtt.c
@@ -2501,7 +2501,7 @@ int intel_vgpu_init_gtt(struct intel_vgpu *vgpu)
 	return create_scratch_page_tree(vgpu);
 }
 
-static void intel_vgpu_destroy_all_ppgtt_mm(struct intel_vgpu *vgpu)
+void intel_vgpu_destroy_all_ppgtt_mm(struct intel_vgpu *vgpu)
 {
 	struct list_head *pos, *n;
 	struct intel_vgpu_mm *mm;