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* [PATCH v2] drm/xe/migrate: Atomicize CCS copy command setup
@ 2025-09-26 13:14 Satyanarayana K V P
  2025-09-26 13:50 ` ✓ CI.KUnit: success for drm/xe/migrate: Atomicize CCS copy command setup (rev2) Patchwork
                   ` (4 more replies)
  0 siblings, 5 replies; 6+ messages in thread
From: Satyanarayana K V P @ 2025-09-26 13:14 UTC (permalink / raw)
  To: intel-xe; +Cc: Satyanarayana K V P, Michal Wajdeczko, Matthew Brost,
	Matthew Auld

The CCS copy command is a 5-dword sequence. If the vCPU halts during
save/restore while this sequence is being programmed, partial writes may
trigger page faults when saving IGPU CCS metadata. Use the VMOVDQU
instruction to write the sequence atomically.

Since VMOVDQU operates on 128-bit chunks, update EMIT_COPY_CCS_DW to emit
8 dwords instead of 5 dwords.

Signed-off-by: Satyanarayana K V P <satyanarayana.k.v.p@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>

---
V1 -> V2:
- Use _memcpy_vmovdqu only for x86 arch and for VF. Else use memcpy
  (Auld, Matthew)
- Fix issues reported by patchworks.
---
 drivers/gpu/drm/xe/xe_migrate.c | 51 +++++++++++++++++++++++++++------
 1 file changed, 42 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_migrate.c b/drivers/gpu/drm/xe/xe_migrate.c
index e2fff2107f68..88ed4d09a97e 100644
--- a/drivers/gpu/drm/xe/xe_migrate.c
+++ b/drivers/gpu/drm/xe/xe_migrate.c
@@ -5,6 +5,7 @@
 
 #include "xe_migrate.h"
 
+#include <asm/fpu/api.h>
 #include <linux/bitfield.h>
 #include <linux/sizes.h>
 
@@ -644,18 +645,39 @@ static void emit_pte(struct xe_migrate *m,
 	}
 }
 
-#define EMIT_COPY_CCS_DW 5
+#ifdef CONFIG_X86
+/*
+ * The CCS copy command is a 5-dword sequence. If the vCPU halts during
+ * save/restore while this sequence is being issued, partial writes may trigger
+ * page faults when saving iGPU CCS metadata. Use the VMOVDQU instruction to
+ * write the sequence atomically.
+ */
+static void memcpy_vmovdqu(void *dst, const void *src)
+{
+	kernel_fpu_begin();
+
+	asm("vmovdqu (%0), %%ymm0\n"
+	    "vmovups %%ymm0,   (%1)\n"
+	    :: "r" (src), "r" (dst) : "memory");
+
+	kernel_fpu_end();
+}
+#endif
+
+#define EMIT_COPY_CCS_DW 8
 static void emit_copy_ccs(struct xe_gt *gt, struct xe_bb *bb,
 			  u64 dst_ofs, bool dst_is_indirect,
 			  u64 src_ofs, bool src_is_indirect,
 			  u32 size)
 {
+	u32 dw[EMIT_COPY_CCS_DW] = {MI_NOOP};
 	struct xe_device *xe = gt_to_xe(gt);
 	u32 *cs = bb->cs + bb->len;
 	u32 num_ccs_blks;
 	u32 num_pages;
 	u32 ccs_copy_size;
 	u32 mocs;
+	u32 i = 0;
 
 	if (GRAPHICS_VERx100(xe) >= 2000) {
 		num_pages = DIV_ROUND_UP(size, XE_PAGE_SIZE);
@@ -673,14 +695,25 @@ static void emit_copy_ccs(struct xe_gt *gt, struct xe_bb *bb,
 		mocs = FIELD_PREP(XY_CTRL_SURF_MOCS_MASK, gt->mocs.uc_index);
 	}
 
-	*cs++ = XY_CTRL_SURF_COPY_BLT |
-		(src_is_indirect ? 0x0 : 0x1) << SRC_ACCESS_TYPE_SHIFT |
-		(dst_is_indirect ? 0x0 : 0x1) << DST_ACCESS_TYPE_SHIFT |
-		ccs_copy_size;
-	*cs++ = lower_32_bits(src_ofs);
-	*cs++ = upper_32_bits(src_ofs) | mocs;
-	*cs++ = lower_32_bits(dst_ofs);
-	*cs++ = upper_32_bits(dst_ofs) | mocs;
+	dw[i++] = XY_CTRL_SURF_COPY_BLT |
+		  (src_is_indirect ? 0x0 : 0x1) << SRC_ACCESS_TYPE_SHIFT |
+		  (dst_is_indirect ? 0x0 : 0x1) << DST_ACCESS_TYPE_SHIFT |
+		  ccs_copy_size;
+	dw[i++] = lower_32_bits(src_ofs);
+	dw[i++] = upper_32_bits(src_ofs) | mocs;
+	dw[i++] = lower_32_bits(dst_ofs);
+	dw[i++] = upper_32_bits(dst_ofs) | mocs;
+
+#ifdef CONFIG_X86
+	if (IS_SRIOV_VF(gt_to_xe(gt)) && static_cpu_has(X86_FEATURE_AVX))
+		memcpy_vmovdqu(cs, dw);
+	else
+		memcpy(cs, dw, sizeof(u32) * EMIT_COPY_CCS_DW);
+#else
+	memcpy(cs, dw, sizeof(u32) * EMIT_COPY_CCS_DW);
+#endif
+
+	cs += EMIT_COPY_CCS_DW;
 
 	bb->len = cs - bb->cs;
 }
-- 
2.43.0


^ permalink raw reply related	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2025-09-26 20:39 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-09-26 13:14 [PATCH v2] drm/xe/migrate: Atomicize CCS copy command setup Satyanarayana K V P
2025-09-26 13:50 ` ✓ CI.KUnit: success for drm/xe/migrate: Atomicize CCS copy command setup (rev2) Patchwork
2025-09-26 14:30 ` ✓ Xe.CI.BAT: " Patchwork
2025-09-26 19:49 ` ✗ Xe.CI.Full: failure " Patchwork
2025-09-26 19:51 ` [PATCH v2] drm/xe/migrate: Atomicize CCS copy command setup Matthew Brost
2025-09-26 20:39 ` Matthew Brost

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