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From: Chris Wilson <chris@chris-wilson.co.uk>
To: intel-gfx@lists.freedesktop.org
Cc: Chris Wilson <chris@chris-wilson.co.uk>,
	CQ Tang <cq.tang@intel.com>,
	stable@vger.kernel.org
Subject: [PATCH] drm/i915: Fix mismatch between misplaced vma check and vma insert
Date: Tue, 15 Dec 2020 20:31:11 +0000	[thread overview]
Message-ID: <20201215203111.650-1-chris@chris-wilson.co.uk> (raw)

When inserting a VMA, we restrict the placement to the low 4G unless the
caller opts into using the full range. This was done to allow usersapce
the opportunity to transition slowly from a 32b address space, and to
avoid breaking inherent 32b assumptions of some commands.

However, for insert we limited ourselves to 4G-4K, but on verification
we allowed the full 4G. This causes some attempts to bind a new buffer
to sporadically fail with -ENOSPC, but at other times be bound
successfully.

commit 48ea1e32c39d ("drm/i915/gen9: Set PIN_ZONE_4G end to 4GB - 1
page") suggests that there is a genuine problem with stateless addressing
that cannot utilize the last page in 4G and so we purposefully excluded
it.

Reported-by: CQ Tang <cq.tang@intel.com>
Fixes: 48ea1e32c39d ("drm/i915/gen9: Set PIN_ZONE_4G end to 4GB - 1 page")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: CQ Tang <cq.tang@intel.com>
Cc: stable@vger.kernel.org
---
 drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
index 193996144c84..2ff32daa50bd 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -382,7 +382,7 @@ eb_vma_misplaced(const struct drm_i915_gem_exec_object2 *entry,
 		return true;
 
 	if (!(flags & EXEC_OBJECT_SUPPORTS_48B_ADDRESS) &&
-	    (vma->node.start + vma->node.size - 1) >> 32)
+	    (vma->node.start + vma->node.size + 4095) >> 32)
 		return true;
 
 	if (flags & __EXEC_OBJECT_NEEDS_MAP &&
-- 
2.20.1


WARNING: multiple messages have this Message-ID (diff)
From: Chris Wilson <chris@chris-wilson.co.uk>
To: intel-gfx@lists.freedesktop.org
Cc: stable@vger.kernel.org, Chris Wilson <chris@chris-wilson.co.uk>
Subject: [Intel-gfx] [PATCH] drm/i915: Fix mismatch between misplaced vma check and vma insert
Date: Tue, 15 Dec 2020 20:31:11 +0000	[thread overview]
Message-ID: <20201215203111.650-1-chris@chris-wilson.co.uk> (raw)

When inserting a VMA, we restrict the placement to the low 4G unless the
caller opts into using the full range. This was done to allow usersapce
the opportunity to transition slowly from a 32b address space, and to
avoid breaking inherent 32b assumptions of some commands.

However, for insert we limited ourselves to 4G-4K, but on verification
we allowed the full 4G. This causes some attempts to bind a new buffer
to sporadically fail with -ENOSPC, but at other times be bound
successfully.

commit 48ea1e32c39d ("drm/i915/gen9: Set PIN_ZONE_4G end to 4GB - 1
page") suggests that there is a genuine problem with stateless addressing
that cannot utilize the last page in 4G and so we purposefully excluded
it.

Reported-by: CQ Tang <cq.tang@intel.com>
Fixes: 48ea1e32c39d ("drm/i915/gen9: Set PIN_ZONE_4G end to 4GB - 1 page")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: CQ Tang <cq.tang@intel.com>
Cc: stable@vger.kernel.org
---
 drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
index 193996144c84..2ff32daa50bd 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -382,7 +382,7 @@ eb_vma_misplaced(const struct drm_i915_gem_exec_object2 *entry,
 		return true;
 
 	if (!(flags & EXEC_OBJECT_SUPPORTS_48B_ADDRESS) &&
-	    (vma->node.start + vma->node.size - 1) >> 32)
+	    (vma->node.start + vma->node.size + 4095) >> 32)
 		return true;
 
 	if (flags & __EXEC_OBJECT_NEEDS_MAP &&
-- 
2.20.1

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             reply	other threads:[~2020-12-15 20:40 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-15 20:31 Chris Wilson [this message]
2020-12-15 20:31 ` [Intel-gfx] [PATCH] drm/i915: Fix mismatch between misplaced vma check and vma insert Chris Wilson
2020-12-15 21:50 ` Tang, CQ
2020-12-15 21:50   ` [Intel-gfx] " Tang, CQ
2020-12-15 22:02   ` Chris Wilson
2020-12-15 22:33     ` Tang, CQ
2020-12-16  0:51     ` Tang, CQ
2020-12-16  8:43       ` Chris Wilson
2020-12-16  9:19         ` Matthew Auld
2020-12-16 17:27         ` Tang, CQ
2020-12-16 20:44           ` Chris Wilson
2020-12-16 21:53             ` Tang, CQ
2020-12-15 23:41 ` [Intel-gfx] ✓ Fi.CI.BAT: success for " Patchwork
2020-12-16  5:35 ` [Intel-gfx] ✗ Fi.CI.IGT: failure " Patchwork

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