[Intel-gfx] [PATCH v6 8/8] drm/i915/gvt: GVTg support context submission pv optimization

[Xiaolin Zhang]

implemented context submission pv optimizaiton within GVTg.

GVTg to read context submission data (elsp_data) from the shared_page
directly without trap cost and eliminate execlist HW behavior emulation
without injecting context switch interrupt to guest under PV
submisison mechanism.

v0: RFC.
v1: rebase.
v2: rebase.
v3: report pv context submission cap and handle VGT_G2V_ELSP_SUBMIT
g2v pv notification.
v4: eliminate execlist HW emulation and don't inject context switch
interrupt to guest under PV submisison mechanism.
v5: rebase.
v6: rebase.

Signed-off-by: Xiaolin Zhang <xiaolin.zhang at intel.com>
---
 drivers/gpu/drm/i915/gvt/execlist.c |  6 ++++++
 drivers/gpu/drm/i915/gvt/handlers.c | 29 ++++++++++++++++++++++++++++-
 drivers/gpu/drm/i915/gvt/vgpu.c     |  1 +
 3 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gvt/execlist.c b/drivers/gpu/drm/i915/gvt/execlist.c
index f21b8fb..e52bfd6 100644
--- a/drivers/gpu/drm/i915/gvt/execlist.c
+++ b/drivers/gpu/drm/i915/gvt/execlist.c
@@ -382,6 +382,9 @@ static int prepare_execlist_workload(struct intel_vgpu_workload *workload)
 	int ring_id = workload->ring_id;
 	int ret;
 
+	if (VGPU_PVCAP(vgpu, PV_SUBMISSION))
+		return 0;
+
 	if (!workload->emulate_schedule_in)
 		return 0;
 
@@ -429,6 +432,9 @@ static int complete_execlist_workload(struct intel_vgpu_workload *workload)
 		goto out;
 	}
 
+	if (VGPU_PVCAP(vgpu, PV_SUBMISSION))
+		goto out;
+
 	ret = emulate_execlist_ctx_schedule_out(execlist, &workload->ctx_desc);
 out:
 	intel_vgpu_unpin_mm(workload->shadow_mm);
diff --git a/drivers/gpu/drm/i915/gvt/handlers.c b/drivers/gpu/drm/i915/gvt/handlers.c
index 1e09c23..9cff9396 100644
--- a/drivers/gpu/drm/i915/gvt/handlers.c
+++ b/drivers/gpu/drm/i915/gvt/handlers.c
@@ -1692,6 +1692,31 @@ static int mmio_read_from_hw(struct intel_vgpu *vgpu,
 	return intel_vgpu_default_mmio_read(vgpu, offset, p_data, bytes);
 }
 
+static int handle_pv_submission(struct intel_vgpu *vgpu, int ring_id)
+{
+	struct intel_vgpu_execlist *execlist;
+	u32 hw_id = vgpu->gvt->dev_priv->engine[ring_id]->hw_id;
+	u32 pv_elsp_off = offsetof(struct gvt_shared_page, buf.pv_elsp);
+	u32 submitted_off = offsetof(struct gvt_shared_page, buf.submitted);
+	bool submitted = true;
+	int ret;
+
+	execlist = &vgpu->submission.execlist[ring_id];
+
+	pv_elsp_off += hw_id * sizeof(struct pv_submission);
+	if (intel_gvt_read_shared_page(vgpu, pv_elsp_off,
+		&execlist->elsp_dwords.data, sizeof(struct pv_submission)))
+		return -EINVAL;
+
+	ret = intel_vgpu_submit_execlist(vgpu, ring_id);
+	if (ret)
+		submitted = false;
+
+	submitted_off += hw_id;
+	ret = intel_gvt_write_shared_page(vgpu, submitted_off, &submitted, 1);
+	return ret;
+}
+
 static int elsp_mmio_write(struct intel_vgpu *vgpu, unsigned int offset,
 		void *p_data, unsigned int bytes)
 {
@@ -1703,8 +1728,10 @@ static int elsp_mmio_write(struct intel_vgpu *vgpu, unsigned int offset,
 	if (WARN_ON(ring_id < 0 || ring_id >= I915_NUM_ENGINES))
 		return -EINVAL;
 
-	execlist = &vgpu->submission.execlist[ring_id];
+	if (VGPU_PVCAP(vgpu, PV_SUBMISSION) && VGT_G2V_PV_SUBMISSION == data)
+		return handle_pv_submission(vgpu, ring_id);
 
+	execlist = &vgpu->submission.execlist[ring_id];
 	execlist->elsp_dwords.data[3 - execlist->elsp_dwords.index] = data;
 	if (execlist->elsp_dwords.index == 3) {
 		ret = intel_vgpu_submit_execlist(vgpu, ring_id);
diff --git a/drivers/gpu/drm/i915/gvt/vgpu.c b/drivers/gpu/drm/i915/gvt/vgpu.c
index 57eaf56..debdb88 100644
--- a/drivers/gpu/drm/i915/gvt/vgpu.c
+++ b/drivers/gpu/drm/i915/gvt/vgpu.c
@@ -51,6 +51,7 @@ void populate_pvinfo_page(struct intel_vgpu *vgpu)
 
 	if (!intel_vtd_active())
 		vgpu_vreg_t(vgpu, vgtif_reg(pv_caps)) = PV_PPGTT_UPDATE;
+	vgpu_vreg_t(vgpu, vgtif_reg(pv_caps)) |= PV_SUBMISSION;
 
 	vgpu_vreg_t(vgpu, vgtif_reg(avail_rs.mappable_gmadr.base)) =
 		vgpu_aperture_gmadr_base(vgpu);
-- 
2.7.4