diff mbox series

[RFC,05/13] drm/i915: enforce min page size for scratch

Message ID 20210822162706.819507-6-ayaz.siddiqui@intel.com (mailing list archive)
State New, archived
Headers show
Series drm/i915/lmem: Enable device memory support for DG2 | expand

Commit Message

Siddiqui, Ayaz A Aug. 22, 2021, 4:26 p.m. UTC 
From: Matthew Auld <matthew.auld@intel.com>

If the device needs 64K minimum GTT pages for device local-memory,
like on XEHPSDV, then we need to fail the allocation if we can't
meet it, instead of falling back to 4K pages, otherwise we can't
safely support the insertion of device local-memory pages for
this vm, since the HW expects the correct physical alignment and
size for every PTE, if we mark the page-table as 64K GTT mode.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Ayaz A Siddiqui <ayaz.siddiqui@intel.com>
---
 drivers/gpu/drm/i915/gt/intel_gtt.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.c b/drivers/gpu/drm/i915/gt/intel_gtt.c
index e137dd32b5b8..e9c01f72fc18 100644
--- a/drivers/gpu/drm/i915/gt/intel_gtt.c
+++ b/drivers/gpu/drm/i915/gt/intel_gtt.c
@@ -333,6 +333,18 @@  int setup_scratch_page(struct i915_address_space *vm)
 		if (size == I915_GTT_PAGE_SIZE_4K)
 			return -ENOMEM;
 
+		/*
+		 * If we need 64K minimum GTT pages for device local-memory,
+		 * like on XEHPSDV, then we need to fail the allocation here,
+		 * otherwise we can't safely support the insertion of
+		 * local-memory pages for this vm, since the HW expects the
+		 * correct physical alignment and size when the page-table is
+		 * operating in 64K GTT mode, which includes any scratch PTEs,
+		 * since userpsace can still touch them.
+		 */
+		if (HAS_64K_PAGES(vm->i915))
+			return -ENOMEM;
+
 		size = I915_GTT_PAGE_SIZE_4K;
 	} while (1);
 }