[PATCH 1/3] drm/xe/xe3p_lpg: flush userptr/shrinker bo cachelines manually

[Tejas Upadhyay <tejas.upadhyay@intel.com>]

"eXtended Architecture" (XA) tagged memory—memory shared between the CPU and GPU
is treated differently from other GPU memory when the Media engine is power-gated.

XA is *always* flushed, like at the end-of-submssion (and maybe other
places), just that internally as an optimisation hw doesn't need to make
that a full flush (which will also include XA) when Media is
off/powergated, since it doesn't need to worry about GT caches vs Media
coherency, and only CPU vs GPU coherency, so can make that flush a
targeted XA flush, since stuff tagged with XA now means it's shared with
the CPU. The main implication is that we now need to somehow flush non-XA before
freeing system memory pages, otherwise dirty cachelines could be flushed after the free
(like if Media suddenly turns on and does a full flush)

V2(MattA): Expand commit description

Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
---
 drivers/gpu/drm/xe/xe_bo.c      |  3 ++-
 drivers/gpu/drm/xe/xe_device.c  | 23 +++++++++++++++++++++++
 drivers/gpu/drm/xe/xe_device.h  |  1 +
 drivers/gpu/drm/xe/xe_userptr.c |  3 ++-
 4 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
index e9180b01a4e4..4455886b211e 100644
--- a/drivers/gpu/drm/xe/xe_bo.c
+++ b/drivers/gpu/drm/xe/xe_bo.c
@@ -689,7 +689,8 @@ static int xe_bo_trigger_rebind(struct xe_device *xe, struct xe_bo *bo,
 
 		if (!xe_vm_in_fault_mode(vm)) {
 			drm_gpuvm_bo_evict(vm_bo, true);
-			continue;
+			if (!xe_device_needs_cache_flush(xe))
+				continue;
 		}
 
 		if (!idle) {
diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
index 743c18e0c580..da2abed94bc0 100644
--- a/drivers/gpu/drm/xe/xe_device.c
+++ b/drivers/gpu/drm/xe/xe_device.c
@@ -1097,6 +1097,29 @@ static void tdf_request_sync(struct xe_device *xe)
 	}
 }
 
+/**
+ * xe_device_needs_cache_flush - Whether the cache needs to be flushed
+ * @xe: The device to check.
+ *
+ * Return: true if the device needs cache flush, false otherwise.
+ */
+bool xe_device_needs_cache_flush(struct xe_device *xe)
+{
+	/* XA is *always* flushed, like at the end-of-submssion (and maybe other
+	 * places), just that internally as an optimisation hw doesn't need to make
+	 * that a full flush (which will also include XA) when Media is
+	 * off/powergated, since it doesn't need to worry about GT caches vs Media
+	 * coherency, and only CPU vs GPU coherency, so can make that flush a
+	 * targeted XA flush, since stuff tagged with XA now means it's shared with
+	 * the CPU. The main implication is that we now need to somehow flush non-XA before
+	 * freeing system memory pages, otherwise dirty cachelines could be flushed after the free
+	 * (like if Media suddenly turns on and does a full flush)
+	 */
+	if (GRAPHICS_VER(xe) >= 35 && !IS_DGFX(xe))
+		return true;
+	return false;
+}
+
 void xe_device_l2_flush(struct xe_device *xe)
 {
 	struct xe_gt *gt;
diff --git a/drivers/gpu/drm/xe/xe_device.h b/drivers/gpu/drm/xe/xe_device.h
index 39464650533b..baf386e0e037 100644
--- a/drivers/gpu/drm/xe/xe_device.h
+++ b/drivers/gpu/drm/xe/xe_device.h
@@ -184,6 +184,7 @@ void xe_device_snapshot_print(struct xe_device *xe, struct drm_printer *p);
 u64 xe_device_canonicalize_addr(struct xe_device *xe, u64 address);
 u64 xe_device_uncanonicalize_addr(struct xe_device *xe, u64 address);
 
+bool xe_device_needs_cache_flush(struct xe_device *xe);
 void xe_device_td_flush(struct xe_device *xe);
 void xe_device_l2_flush(struct xe_device *xe);
 
diff --git a/drivers/gpu/drm/xe/xe_userptr.c b/drivers/gpu/drm/xe/xe_userptr.c
index e120323c43bc..b435ea7f9b66 100644
--- a/drivers/gpu/drm/xe/xe_userptr.c
+++ b/drivers/gpu/drm/xe/xe_userptr.c
@@ -114,7 +114,8 @@ static void __vma_userptr_invalidate(struct xe_vm *vm, struct xe_userptr_vma *uv
 				    false, MAX_SCHEDULE_TIMEOUT);
 	XE_WARN_ON(err <= 0);
 
-	if (xe_vm_in_fault_mode(vm) && userptr->initial_bind) {
+	if ((xe_vm_in_fault_mode(vm) || xe_device_needs_cache_flush(vm->xe)) &&
+	    userptr->initial_bind) {
 		err = xe_vm_invalidate_vma(vma);
 		XE_WARN_ON(err);
 	}
-- 
2.52.0