[Intel-gfx] [v1 04/10] drm/i915: master irq pvmmio optimization

[Xiaolin Zhang]

Master irq register is accessed twice every irq handling, then trapped
to SOS very frequently. Optimize it by moving master irq register
to share page, writing don't need be trapped.

When need enable irq to let SOS inject irq timely, use another pvmmio
register to achieve this purpose. So avoid one trap when we disable
master irq.

Use PVMMIO_MASTER_IRQ to control this level of pvmmio optimization.

v1: rebase
v0: RFC

Signed-off-by: Xiaolin Zhang <xiaolin.zhang at intel.com>
---
 drivers/gpu/drm/i915/i915_irq.c    | 29 +++++++++++++++++++++++------
 drivers/gpu/drm/i915/i915_pvinfo.h |  3 ++-
 drivers/gpu/drm/i915/i915_vgpu.c   |  2 +-
 3 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 2e24227..54db60a 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2901,7 +2901,10 @@ static irqreturn_t gen8_irq_handler(int irq, void *arg)
 	if (!master_ctl)
 		return IRQ_NONE;
 
-	I915_WRITE_FW(GEN8_MASTER_IRQ, 0);
+	if (PVMMIO_LEVEL_ENABLE(dev_priv, PVMMIO_MASTER_IRQ))
+		dev_priv->vgpu.shared_page->disable_irq = 1;
+	else
+		I915_WRITE_FW(GEN8_MASTER_IRQ, 0);
 
 	/* Find, clear, then process each source of interrupt */
 	gen8_gt_irq_ack(dev_priv, master_ctl, gt_iir);
@@ -2913,7 +2916,12 @@ static irqreturn_t gen8_irq_handler(int irq, void *arg)
 		enable_rpm_wakeref_asserts(dev_priv);
 	}
 
-	I915_WRITE_FW(GEN8_MASTER_IRQ, GEN8_MASTER_IRQ_CONTROL);
+	if (PVMMIO_LEVEL_ENABLE(dev_priv, PVMMIO_MASTER_IRQ)) {
+		dev_priv->vgpu.shared_page->disable_irq = 0;
+		__raw_i915_write32(dev_priv, vgtif_reg(check_pending_irq), 1);
+	} else {
+		I915_WRITE_FW(GEN8_MASTER_IRQ, GEN8_MASTER_IRQ_CONTROL);
+	}
 
 	gen8_gt_irq_handler(dev_priv, master_ctl, gt_iir);
 
@@ -3598,8 +3606,12 @@ static void gen8_irq_reset(struct drm_device *dev)
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	int pipe;
 
-	I915_WRITE(GEN8_MASTER_IRQ, 0);
-	POSTING_READ(GEN8_MASTER_IRQ);
+	if (PVMMIO_LEVEL_ENABLE(dev_priv, PVMMIO_MASTER_IRQ)) {
+		dev_priv->vgpu.shared_page->disable_irq = 1;
+	} else {
+		I915_WRITE(GEN8_MASTER_IRQ, 0);
+		POSTING_READ(GEN8_MASTER_IRQ);
+	}
 
 	gen8_gt_irq_reset(dev_priv);
 
@@ -4244,8 +4256,13 @@ static int gen8_irq_postinstall(struct drm_device *dev)
 	if (HAS_PCH_SPLIT(dev_priv))
 		ibx_irq_postinstall(dev);
 
-	I915_WRITE(GEN8_MASTER_IRQ, GEN8_MASTER_IRQ_CONTROL);
-	POSTING_READ(GEN8_MASTER_IRQ);
+	if (PVMMIO_LEVEL_ENABLE(dev_priv, PVMMIO_MASTER_IRQ)) {
+		dev_priv->vgpu.shared_page->disable_irq = 0;
+		__raw_i915_write32(dev_priv, vgtif_reg(check_pending_irq), 1);
+	} else {
+		I915_WRITE(GEN8_MASTER_IRQ, GEN8_MASTER_IRQ_CONTROL);
+		POSTING_READ(GEN8_MASTER_IRQ);
+	}
 
 	return 0;
 }
diff --git a/drivers/gpu/drm/i915/i915_pvinfo.h b/drivers/gpu/drm/i915/i915_pvinfo.h
index 179d558..1e24c45 100644
--- a/drivers/gpu/drm/i915/i915_pvinfo.h
+++ b/drivers/gpu/drm/i915/i915_pvinfo.h
@@ -143,8 +143,9 @@ struct vgt_if {
 		u32 lo;
 		u32 hi;
 	} shared_page_gpa;
+	u32 check_pending_irq;
 
-	u32  rsv7[0x200 - 27];    /* pad to one page */
+	u32  rsv7[0x200 - 28];    /* pad to one page */
 } __packed;
 
 #define vgtif_reg(x) \
diff --git a/drivers/gpu/drm/i915/i915_vgpu.c b/drivers/gpu/drm/i915/i915_vgpu.c
index 84241a7..6471574 100644
--- a/drivers/gpu/drm/i915/i915_vgpu.c
+++ b/drivers/gpu/drm/i915/i915_vgpu.c
@@ -66,7 +66,7 @@ void i915_check_vgpu(struct drm_i915_private *dev_priv)
 
 	BUILD_BUG_ON(sizeof(struct vgt_if) != VGT_PVINFO_SIZE);
 
-	dev_priv->vgpu.pv_caps = PVMMIO_ELSP_SUBMIT;
+	dev_priv->vgpu.pv_caps = PVMMIO_ELSP_SUBMIT | PVMMIO_MASTER_IRQ;
 
 	magic = __raw_i915_read64(dev_priv, vgtif_reg(magic));
 	if (magic != VGT_MAGIC)
-- 
2.7.4