From 323d0c425b9341942ac7603fa5788ecb3ea47bb3 Mon Sep 17 00:00:00 2001
From: Matthew Auld <matthew.auld@intel.com>
Date: Wed, 8 Dec 2021 19:46:13 +0530
Subject: drm/i915: enforce min page size for scratch
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Git-commit: f122a46a637f9231433d30aa1f9a199f8688cb97
Patch-mainline: v5.17-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
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.
v2: s/userpsace/userspace [Thomas]
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211208141613.7251-5-ramalingam.c@intel.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/i915/gt/intel_gtt.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.c b/drivers/gpu/drm/i915/gt/intel_gtt.c
index 20372bcb394a..30683c06b344 100644
--- a/drivers/gpu/drm/i915/gt/intel_gtt.c
+++ b/drivers/gpu/drm/i915/gt/intel_gtt.c
@@ -338,6 +338,18 @@ 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 userspace can still touch them.
+ */
+ if (HAS_64K_PAGES(vm->i915))
+ return -ENOMEM;
+
size = I915_GTT_PAGE_SIZE_4K;
} while (1);
}
--
2.38.1