[PATCH v2 1/1] i915/i915_driver: move intel_gvt_init() level higher

["Michał Grzelak" <michal.grzelak@intel.com>]

Both initialisation and removal of GVT happen at different abstraction
levels. Hence caller of i915_driver_hw_probe() has no way of knowing
status of intel_gvt_init(). This can lead to an unbalanced number of
calls of intel_gvt_init() and intel_gvt_driver_remove() since GVT error
path is currently handled in i915_driver_probe(). One such scenario has
been seen with i915_driver_hw_probe() fault injection, which caused
double entry deletion and list corruption.

Move intel_gvt_init() up to i915_driver_probe(). Add out_cleanup_gvt
error path for removing gvt. Trigger it only after intel_gvt_init()
succeeded.

In case intel_gvt_init() failed, theoretically we should follow err_msi
error path. That is actually impossible since call to intel_gvt_init()
unconditionally returns 0, although it claims to return negative error
code on failure. Thus follow standard out_cleanup_hw error path on a
hypothetical future intel_gvt_init() failure. Remove err_msi label from
i915_driver_hw_probe() since intel_gvt_init() was the only user of it.

Changelog:
v1->v2
- don't move err_msi error path from i915_driver_hw_probe (Jani)
- rewrite commit message

Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/15481
Signed-off-by: Michał Grzelak <michal.grzelak@intel.com>
---
 drivers/gpu/drm/i915/i915_driver.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c
index 1e087dfe03d0..114f73902746 100644
--- a/drivers/gpu/drm/i915/i915_driver.c
+++ b/drivers/gpu/drm/i915/i915_driver.c
@@ -557,10 +557,6 @@ static int i915_driver_hw_probe(struct drm_i915_private *dev_priv)
 			drm_dbg(&dev_priv->drm, "can't enable MSI");
 	}
 
-	ret = intel_gvt_init(dev_priv);
-	if (ret)
-		goto err_msi;
-
 	intel_opregion_setup(display);
 
 	ret = i915_pcode_init(dev_priv);
@@ -581,7 +577,6 @@ static int i915_driver_hw_probe(struct drm_i915_private *dev_priv)
 
 err_opregion:
 	intel_opregion_cleanup(display);
-err_msi:
 	if (pdev->msi_enabled)
 		pci_disable_msi(pdev);
 err_mem_regions:
@@ -870,9 +865,13 @@ int i915_driver_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (ret < 0)
 		goto out_cleanup_mmio;
 
+	ret = intel_gvt_init(i915);
+	if (ret)
+		goto out_cleanup_hw;
+
 	ret = intel_display_driver_probe_noirq(display);
 	if (ret < 0)
-		goto out_cleanup_hw;
+		goto out_cleanup_gvt;
 
 	ret = intel_irq_install(i915);
 	if (ret)
@@ -921,6 +920,8 @@ int i915_driver_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	intel_irq_uninstall(i915);
 out_cleanup_modeset:
 	intel_display_driver_remove_nogem(display);
+out_cleanup_gvt:
+	intel_gvt_driver_remove(i915);
 out_cleanup_hw:
 	i915_driver_hw_remove(i915);
 	intel_memory_regions_driver_release(i915);
@@ -928,7 +929,6 @@ int i915_driver_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	i915_gem_drain_freed_objects(i915);
 	i915_ggtt_driver_late_release(i915);
 out_cleanup_mmio:
-	intel_gvt_driver_remove(i915);
 	i915_driver_mmio_release(i915);
 out_runtime_pm_put:
 	enable_rpm_wakeref_asserts(&i915->runtime_pm);
-- 
2.45.2