[PATCH 1/1] drm/xe: fixing endless PF range response

[fei.yang@intel.com]

From: Fei Yang <fei.yang@intel.com>

[334.635636] PF range response: start=0x80200000  end=0xc0200000 pages=262144 (more ranges pending)
...
[519.065737] PF range response: start=0x5ca140200000 ...  (still going, 94888 messages logged)

SVM handler narrows the serviced range through functions
xe_pagefault_set_[start|end]_addr, which updates only the
consumer.[page|end]_addr. However a different field is used
for "immediate ack" cache, xe4_guc_ack_fault_range() reads
vma_info. This causes the ack fault to loop through the
whole address space with 1G pages, and that is wrong and
the loop takes a long while to complete.

VLK-99796

Assisted-by: GitHub_Copilot:claude-opus-5
Signed-off-by: Fei Yang <fei.yang@intel.com>
---
 drivers/gpu/drm/xe/xe_pagefault.c | 7 ++++++-
 drivers/gpu/drm/xe/xe_pagefault.h | 2 ++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xe/xe_pagefault.c b/drivers/gpu/drm/xe/xe_pagefault.c
index 5247321c805ec..72dfe27025736 100644
--- a/drivers/gpu/drm/xe/xe_pagefault.c
+++ b/drivers/gpu/drm/xe/xe_pagefault.c
@@ -694,6 +694,8 @@ static void xe_pagefault_queue_work(struct work_struct *w)
 		/* Last fault same address, ack immediately */
 		if (xe_pagefault_match(pf, cache_start, cache_end, cache_asid)) {
 			xe_gt_stats_incr(gt, XE_GT_STATS_ID_LAST_PAGEFAULT_COUNT, 1);
+			xe_pagefault_set_start_addr(pf, cache_start);
+			xe_pagefault_set_end_addr(pf, cache_end);
 			goto ack_fault;
 		}
 
@@ -751,9 +753,12 @@ static void xe_pagefault_queue_work(struct work_struct *w)
 				pf = xe_pagefault_queue_unchain_requeue(pf_queue, pf, gt);
 
 			/* Ensure resets are safe */
-			if (pf)
+			if (pf) {
 				pf->consumer.alloc_state =
 					XE_PAGEFAULT_ALLOC_STATE_ACTIVE;
+				xe_pagefault_set_start_addr(pf, cache_start);
+				xe_pagefault_set_end_addr(pf, cache_end);
+			}
 
 			spin_unlock_irq(&pf_queue->lock);
 		}
diff --git a/drivers/gpu/drm/xe/xe_pagefault.h b/drivers/gpu/drm/xe/xe_pagefault.h
index 799c984dee84f..5ce2f6ed10c56 100644
--- a/drivers/gpu/drm/xe/xe_pagefault.h
+++ b/drivers/gpu/drm/xe/xe_pagefault.h
@@ -98,6 +98,7 @@ xe_pagefault_set_end_addr(struct xe_pagefault *pf, u64 end_addr)
 {
 	pf->consumer.end_addr &= ~XE_PAGEFAULT_END_ADDR_MASK;
 	pf->consumer.end_addr |= end_addr;
+	pf->consumer.vma_info.end_addr = end_addr;
 }
 
 /**
@@ -137,6 +138,7 @@ xe_pagefault_set_start_addr(struct xe_pagefault *pf, u64 start_addr)
 {
 	pf->consumer.page_addr &= XE_PAGEFAULT_ERROR_MASK;
 	pf->consumer.page_addr |= (start_addr & ~XE_PAGEFAULT_ERROR_MASK);
+	pf->consumer.vma_info.start_addr = start_addr;
 }
 
 /**
-- 
2.43.0