drm/i915/gem: Don't allow changing the VM on running contexts (v4)

When the APIs were added to manage VMs more directly from userspace, the
questionable choice was made to allow changing out the VM on a context
at any time.  This is horribly racy and there's absolutely no reason why
any userspace would want to do this outside of testing that exact race.
By removing support for CONTEXT_PARAM_VM from ctx_setparam, we make it
impossible to change out the VM after the context has been fully
created.  This lets us delete a bunch of deferred task code as well as a
duplicated (and slightly different) copy of the code which programs the
PPGTT registers.

v2 (Jason Ekstrand):
 - Expand the commit message

v3 (Daniel Vetter):
 - Don't drop the __rcu on the vm pointer

v4 (Jason Ekstrand):
 - Make it more obvious that I915_CONTEXT_PARAM_VM returns -EINVAL

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210708154835.528166-26-jason@jlekstrand.net

1 files changed, 0 insertions, 119 deletions

diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
index dbcfa28a9d91..92544a174cc9 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
@@ -1875,125 +1875,6 @@ out_file:
 	return err;
 }
 
-static bool skip_unused_engines(struct intel_context *ce, void *data)
-{
-	return !ce->state;
-}
-
-static void mock_barrier_task(void *data)
-{
-	unsigned int *counter = data;
-
-	++*counter;
-}
-
-static int mock_context_barrier(void *arg)
-{
-#undef pr_fmt
-#define pr_fmt(x) "context_barrier_task():" # x
-	struct drm_i915_private *i915 = arg;
-	struct i915_gem_context *ctx;
-	struct i915_request *rq;
-	unsigned int counter;
-	int err;
-
-	/*
-	 * The context barrier provides us with a callback after it emits
-	 * a request; useful for retiring old state after loading new.
-	 */
-
-	ctx = mock_context(i915, "mock");
-	if (!ctx)
-		return -ENOMEM;
-
-	counter = 0;
-	err = context_barrier_task(ctx, 0, NULL, NULL, NULL,
-				   mock_barrier_task, &counter);
-	if (err) {
-		pr_err("Failed at line %d, err=%d\n", __LINE__, err);
-		goto out;
-	}
-	if (counter == 0) {
-		pr_err("Did not retire immediately with 0 engines\n");
-		err = -EINVAL;
-		goto out;
-	}
-
-	counter = 0;
-	err = context_barrier_task(ctx, ALL_ENGINES, skip_unused_engines,
-				   NULL, NULL, mock_barrier_task, &counter);
-	if (err) {
-		pr_err("Failed at line %d, err=%d\n", __LINE__, err);
-		goto out;
-	}
-	if (counter == 0) {
-		pr_err("Did not retire immediately for all unused engines\n");
-		err = -EINVAL;
-		goto out;
-	}
-
-	rq = igt_request_alloc(ctx, i915->gt.engine[RCS0]);
-	if (IS_ERR(rq)) {
-		pr_err("Request allocation failed!\n");
-		goto out;
-	}
-	i915_request_add(rq);
-
-	counter = 0;
-	context_barrier_inject_fault = BIT(RCS0);
-	err = context_barrier_task(ctx, ALL_ENGINES, NULL, NULL, NULL,
-				   mock_barrier_task, &counter);
-	context_barrier_inject_fault = 0;
-	if (err == -ENXIO)
-		err = 0;
-	else
-		pr_err("Did not hit fault injection!\n");
-	if (counter != 0) {
-		pr_err("Invoked callback on error!\n");
-		err = -EIO;
-	}
-	if (err)
-		goto out;
-
-	counter = 0;
-	err = context_barrier_task(ctx, ALL_ENGINES, skip_unused_engines,
-				   NULL, NULL, mock_barrier_task, &counter);
-	if (err) {
-		pr_err("Failed at line %d, err=%d\n", __LINE__, err);
-		goto out;
-	}
-	mock_device_flush(i915);
-	if (counter == 0) {
-		pr_err("Did not retire on each active engines\n");
-		err = -EINVAL;
-		goto out;
-	}
-
-out:
-	mock_context_close(ctx);
-	return err;
-#undef pr_fmt
-#define pr_fmt(x) x
-}
-
-int i915_gem_context_mock_selftests(void)
-{
-	static const struct i915_subtest tests[] = {
-		SUBTEST(mock_context_barrier),
-	};
-	struct drm_i915_private *i915;
-	int err;
-
-	i915 = mock_gem_device();
-	if (!i915)
-		return -ENOMEM;
-
-	err = i915_subtests(tests, i915);
-
-	mock_destroy_device(i915);
-	return err;
-}
-
 int i915_gem_context_live_selftests(struct drm_i915_private *i915)
 {
 	static const struct i915_subtest tests[] = {