[PATCH v2] drm/i915/gt: Report full vm address range

[Andi Shyti]

Commit 9bb66c179f50 ("drm/i915: Reserve some kernel space per
vm") has reserved an object for kernel space usage.

Userspace, though, needs to know the full address range.

In the former patch the reserved space was substructed from the
total amount of the VM space. Add it back when the user requests
the GTT size through ioctl (I915_CONTEXT_PARAM_GTT_SIZE).

Fixes: 9bb66c179f50 ("drm/i915: Reserve some kernel space per vm")
Signed-off-by: Andi Shyti <andi.shyti at linux.intel.com>
Cc: Andrzej Hajda <andrzej.hajda at intel.com>
Cc: Chris Wilson <chris.p.wilson at linux.intel.com>
Cc: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
Cc: Michal Mrozek <michal.mrozek at intel.com>
Cc: Nirmoy Das <nirmoy.das at intel.com>
Cc: <stable at vger.kernel.org> # v6.2+
Acked-by: Michal Mrozek <michal.mrozek at intel.com>
Acked-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
---
Hi,

Just proposing a different implementation that doesn't affect
i915 internally but provides the same result. Instead of not
substracting the space during the reservation, I add it back 
during the ioctl call.

All the "vm->rsvd.vma->node.size" looks a bit ugly, but that's
how it is. Maybe a comment can help to understand better why
there is this addition.

I kept the Ack from Michal and Lionel, because the outcome from
userspace perspactive doesn't really change.

Andi

 drivers/gpu/drm/i915/gem/i915_gem_context.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index 81f65cab1330..60d9e7fe33b3 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -2454,7 +2454,7 @@ int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data,
 	case I915_CONTEXT_PARAM_GTT_SIZE:
 		args->size = 0;
 		vm = i915_gem_context_get_eb_vm(ctx);
-		args->value = vm->total;
+		args->value = vm->total + vm->rsvd.vma->node.size;
 		i915_vm_put(vm);
 
 		break;
-- 
2.43.0