[PATCH v2 i-g-t 1/6] lib/igt_device_sriov: Add generic SR-IOV exit cleanup helper

[Marcin Bernatowicz <marcin.bernatowicz@linux.intel.com>]

Add SR-IOV exit-handler helpers.

The handler provides best-effort cleanup on exit: optional callback,
VF disable, and optional autoprobe restore.
Add a helper to clear handler state after normal teardown.

Signed-off-by: Marcin Bernatowicz <marcin.bernatowicz@linux.intel.com>
Cc: Adam Miszczak <adam.miszczak@linux.intel.com>
Cc: Jakub Kolakowski <jakub1.kolakowski@intel.com>
Cc: Lukasz Laguna <lukasz.laguna@intel.com>
---
v2: Always try to restore sriov_drivers_autoprobe. (Lukasz)
---
 lib/igt_sriov_device.c | 91 ++++++++++++++++++++++++++++++++++++++++++
 lib/igt_sriov_device.h |  5 +++
 2 files changed, 96 insertions(+)

diff --git a/lib/igt_sriov_device.c b/lib/igt_sriov_device.c
index 8f2cfa50f..da1557010 100644
--- a/lib/igt_sriov_device.c
+++ b/lib/igt_sriov_device.c
@@ -546,3 +546,94 @@ bool intel_is_vf_device(int fd)
 
 	return (value & 1) != 0;
 }
+
+struct sriov_exit_handler_ctx {
+	int pf;
+	bool restore_autoprobe;
+	bool autoprobe;
+	igt_sriov_exit_cleanup_fn cleanup_fn;
+	void *cleanup_data;
+};
+
+static struct sriov_exit_handler_ctx sriov_exit_ctx = {
+	.pf = -1,
+};
+
+static void sriov_exit_handler_release_fd(void)
+{
+	if (sriov_exit_ctx.pf < 0)
+		return;
+
+	__drm_close_driver(sriov_exit_ctx.pf);
+	sriov_exit_ctx.pf = -1;
+}
+
+static void sriov_exit_handler(int sig)
+{
+	if (sriov_exit_ctx.pf < 0)
+		return;
+
+	igt_sriov_disable_vfs(sriov_exit_ctx.pf);
+
+	if (sriov_exit_ctx.cleanup_fn)
+		sriov_exit_ctx.cleanup_fn(sriov_exit_ctx.pf, sig,
+					  sriov_exit_ctx.cleanup_data);
+
+	if (sriov_exit_ctx.autoprobe)
+		igt_sriov_enable_driver_autoprobe(sriov_exit_ctx.pf);
+	else
+		igt_sriov_disable_driver_autoprobe(sriov_exit_ctx.pf);
+}
+
+/**
+ * igt_sriov_install_exit_handler - Install best-effort SR-IOV cleanup handler
+ * @pf: PF device file descriptor
+ * @cleanup_fn: Optional callback invoked after VF disable
+ * @cleanup_data: Opaque callback data
+ *
+ * Registers a process-exit cleanup routine for SR-IOV tests. The handler runs
+ * from normal and signal-triggered exits (when possible), disables VFs,
+ * invokes @cleanup_fn if provided (passing signal number, or 0 on normal
+ * exit), and restores the original autoprobe setting captured at
+ * installation time. Tests that perform full explicit teardown should call
+ * igt_sriov_clear_exit_handler() once that teardown succeeds. An internal
+ * duplicate of @pf is kept so cleanup remains usable even if the caller closes
+ * the original DRM fd before process exit.
+ */
+void igt_sriov_install_exit_handler(int pf,
+				    igt_sriov_exit_cleanup_fn cleanup_fn,
+				    void *cleanup_data)
+{
+	int pf_dup;
+
+	if (!igt_sriov_is_pf(pf))
+		return;
+
+	pf_dup = dup(pf);
+	igt_assert_f(pf_dup >= 0, "Failed to duplicate PF fd (%s)\n",
+		     strerror(errno));
+
+	sriov_exit_handler_release_fd();
+
+	sriov_exit_ctx.pf = pf_dup;
+	sriov_exit_ctx.autoprobe = igt_sriov_is_driver_autoprobe_enabled(pf_dup);
+	sriov_exit_ctx.cleanup_fn = cleanup_fn;
+	sriov_exit_ctx.cleanup_data = cleanup_data;
+
+	igt_install_exit_handler(sriov_exit_handler);
+}
+
+/**
+ * igt_sriov_clear_exit_handler - Disable SR-IOV exit cleanup context
+ *
+ * Clears the active SR-IOV cleanup context, used when a test has completed
+ * explicit teardown and no longer needs best-effort cleanup on process exit.
+ */
+void igt_sriov_clear_exit_handler(void)
+{
+	sriov_exit_handler_release_fd();
+	sriov_exit_ctx.restore_autoprobe = false;
+	sriov_exit_ctx.autoprobe = false;
+	sriov_exit_ctx.cleanup_fn = NULL;
+	sriov_exit_ctx.cleanup_data = NULL;
+}
diff --git a/lib/igt_sriov_device.h b/lib/igt_sriov_device.h
index a417b30d8..4e4ba230a 100644
--- a/lib/igt_sriov_device.h
+++ b/lib/igt_sriov_device.h
@@ -36,6 +36,11 @@ bool igt_sriov_device_reset_exists(int pf, unsigned int vf_num);
 bool igt_sriov_device_reset(int pf, unsigned int vf_num);
 bool intel_is_vf_device(int device);
 const char *igt_sriov_func_str(unsigned int vf_num);
+typedef void (*igt_sriov_exit_cleanup_fn)(int pf, int sig, void *user_data);
+void igt_sriov_install_exit_handler(int pf,
+				    igt_sriov_exit_cleanup_fn cleanup_fn,
+				    void *cleanup_data);
+void igt_sriov_clear_exit_handler(void);
 
 /**
  * __is_valid_range - Helper to check VF range is valid
-- 
2.43.0