On 8/25/2023 7:33 AM, Javier Pello wrote:
There is an assertion in ggtt_reserve_guc_top that the global GTT
is of size at least GUC_GGTT_TOP, which is not the case on a 32-bit
platform; see commit 562d55d991b39ce376c492df2f7890fd6a541ffc
("drm/i915/bdw: Only use 2g GGTT for 32b platforms"). If GEM_BUG_ON
is enabled, this triggers a BUG(); if GEM_BUG_ON is disabled, the
subsequent reservation fails and the driver fails to initialise
the device:
i915 0000:00:02.0: [drm:i915_init_ggtt [i915]] Failed to reserve top of GGTT for GuC
i915 0000:00:02.0: Device initialization failed (-28)
i915 0000:00:02.0: Please file a bug on drm/i915; see https://gitlab.freedesktop.org/drm/intel/-/wikis/How-to-file-i915-bugs for details.
i915: probe of 0000:00:02.0 failed with error -28
Make the reservation at the top of the available space, whatever
that is, instead of assuming that the top will be GUC_GGTT_TOP.
Fixes: 911800765ef6 ("drm/i915/uc: Reserve upper range of GGTT")
For tracking, it might be good to also add:
Link: https://gitlab.freedesktop.org/drm/intel/-/issues/9080
Signed-off-by: Javier Pello <devel@xxxxxxxx>
Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx # v5.3+
Need the full CC list here, so that when the patch gets back-ported the
relevant developers get automatically added.
---
drivers/gpu/drm/i915/gt/intel_ggtt.c | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_ggtt.c b/drivers/gpu/drm/i915/gt/intel_ggtt.c
index e9328e1a..0157bebb 100644
--- a/drivers/gpu/drm/i915/gt/intel_ggtt.c
+++ b/drivers/gpu/drm/i915/gt/intel_ggtt.c
@@ -511,20 +511,29 @@ void intel_ggtt_unbind_vma(struct i915_address_space *vm,
vm->clear_range(vm, vma_res->start, vma_res->vma_size);
}
+/* Reserve the top of the GuC address space for firmware images. Addresses
+ * beyond GUC_GGTT_TOP in the GuC address space are inaccessible by GuC,
+ * which makes for a suitable range to hold GuC/HuC firmware images if the
+ * size of the GGTT is 4G. However, on a 32-bit platform the size of the GGTT
+ * is limited to 2G, which is less than GUC_GGTT_TOP, but we reserve a chunk
+ * of the same size anyway, which is far more than needed, to keep the logic
+ * in uc_fw_ggtt_offset() simple. */
Style: multi-line comment should be formatted as:
/*
* Text
* more text
*/
+#define GUC_TOP_RESERVE_SIZE (SZ_4G - GUC_GGTT_TOP)
+
static int ggtt_reserve_guc_top(struct i915_ggtt *ggtt)
{
- u64 size;
+ u64 offset;
int ret;
if (!intel_uc_uses_guc(&ggtt->vm.gt->uc))
return 0;
- GEM_BUG_ON(ggtt->vm.total <= GUC_GGTT_TOP);
- size = ggtt->vm.total - GUC_GGTT_TOP;
+ GEM_BUG_ON(ggtt->vm.total <= GUC_TOP_RESERVE_SIZE);
+ offset = ggtt->vm.total - GUC_TOP_RESERVE_SIZE;
- ret = i915_gem_gtt_reserve(&ggtt->vm, NULL, &ggtt->uc_fw, size,
- GUC_GGTT_TOP, I915_COLOR_UNEVICTABLE,
- PIN_NOEVICT);
+ ret = i915_gem_gtt_reserve(&ggtt->vm, NULL, &ggtt->uc_fw,
+ GUC_TOP_RESERVE_SIZE, offset,
+ I915_COLOR_UNEVICTABLE, PIN_NOEVICT);
The code change looks good to me, so with the style fix and the
additions to the commit message this is:
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx>
Daniele
if (ret)
drm_dbg(&ggtt->vm.i915->drm,
"Failed to reserve top of GGTT for GuC\n");
