On 21/02/2023 17:14, Cavitt, Jonathan wrote:
-----Original Message-----
From: Auld, Matthew <matthew.auld@xxxxxxxxx>
Sent: Tuesday, February 21, 2023 8:33 AM
To: Cavitt, Jonathan <jonathan.cavitt@xxxxxxxxx>
Cc: Dutt, Sudeep <sudeep.dutt@xxxxxxxxx>; Siddiqui, Ayaz A <ayaz.siddiqui@xxxxxxxxx>; intel-gfx@xxxxxxxxxxxxxxxxxxxxx
Subject: Re: [PATCH] gen8_ppgtt: Use correct huge page manager for MTL
On 21/02/2023 16:28, Cavitt, Jonathan wrote:
-----Original Message-----
From: Auld, Matthew <matthew.auld@xxxxxxxxx>
Sent: Tuesday, February 21, 2023 8:06 AM
To: Cavitt, Jonathan <jonathan.cavitt@xxxxxxxxx>; intel-gfx@xxxxxxxxxxxxxxxxxxxxx
Cc: Dutt, Sudeep <sudeep.dutt@xxxxxxxxx>; Siddiqui, Ayaz A <ayaz.siddiqui@xxxxxxxxx>
Subject: Re: [PATCH] gen8_ppgtt: Use correct huge page manager for MTL
On 17/02/2023 19:18, Jonathan Cavitt wrote:
MTL currently uses gen8_ppgtt_insert_huge when managing huge pages. This is because
MTL reports as not supporting 64K pages, or more accurately, the system that reports
whether a platform has 64K pages reports false for MTL. This is only half correct,
as the 64K page support reporting system only cares about 64K page support for LMEM,
which MTL doesn't have.
MTL should be using xehpsdv_ppgtt_insert_huge. However, simply changing over to
using that manager doesn't resolve the issue because MTL is expecting the virtual
address space for the page table to be flushed after initialization, so we must also
add a flush statement there.
Signed-off-by: Jonathan Cavitt <jonathan.cavitt@xxxxxxxxx>
Reviewed-by: Matthew Auld <matthew.auld@xxxxxxxxx>
Although it looks like the hugepage mock tests are failing with this. I
assume the mock device just uses some "max" gen version or so, which now
triggers this path. Any ideas for that?
With this patch applied, multiple calls to the hugepages live selftest result in a kernel panic.
If the mock tests are run immediately after the live ones, that would explain this behavior.
I was informed when this was initially debugged that the error was a known IOMMU issue
rather than some novel regression, though it's hard to tell if that was just hopeful optimism
or not at this point.
In the test results we now get:
6> [183.420316] i915: Running
i915_gem_huge_page_mock_selftests/igt_mock_exhaust_device_supported_pages
<6> [183.436978] i915: Running
i915_gem_huge_page_mock_selftests/igt_mock_memory_region_huge_pages
<6> [183.445777] i915: Running
i915_gem_huge_page_mock_selftests/igt_mock_ppgtt_misaligned_dma
<6> [183.904531] i915: Running
i915_gem_huge_page_mock_selftests/igt_mock_ppgtt_huge_fill
<3> [183.912658] gtt=69632, expected=4096, size=69632, single=yes
<3> [183.912784] i915/i915_gem_huge_page_mock_selftests:
igt_mock_ppgtt_huge_fill failed with error -22
if (expected_gtt & I915_GTT_PAGE_SIZE_4K)
expected_gtt &= ~I915_GTT_PAGE_SIZE_64K;
I don't know why we're doing that to expected_gtt, but that seems to be the cause of the
problem in this case.
I think it's due to the older huge page model, where 64K requires the
entire page-table to all use 64K pages underneath (pde level hint), so
if we see 4K in there somewhere then we don't expect to get back 64K
GTT. But on newer HW we now have have pte level hint, so I think the
above can just be removed with this patch, since that's what the mock
device now uses.
-Jonathan Cavitt
I didn't look any deeper than that though. Note that this a just a
mock/fake device. I don't think its IOMMU related.
-Jonathan Cavitt
---
drivers/gpu/drm/i915/gt/gen8_ppgtt.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
index 4daaa6f55668..9c571185395f 100644
--- a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
+++ b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
@@ -570,6 +570,7 @@ xehpsdv_ppgtt_insert_huge(struct i915_address_space *vm,
}
} while (rem >= page_size && index < max);
+ drm_clflush_virt_range(vaddr, PAGE_SIZE);
vma_res->page_sizes_gtt |= page_size;
} while (iter->sg && sg_dma_len(iter->sg));
}
@@ -707,7 +708,7 @@ static void gen8_ppgtt_insert(struct i915_address_space *vm,
struct sgt_dma iter = sgt_dma(vma_res);
if (vma_res->bi.page_sizes.sg > I915_GTT_PAGE_SIZE) {
- if (HAS_64K_PAGES(vm->i915))
+ if (GRAPHICS_VER_FULL(vm->i915) >= IP_VER(12, 50))
xehpsdv_ppgtt_insert_huge(vm, vma_res, &iter, cache_level, flags);
else
gen8_ppgtt_insert_huge(vm, vma_res, &iter, cache_level, flags);
