[PATCH v3] zcrypt: handle AP Info notification from CHSC SEI command

[Tony Krowiak]

The current AP bus implementation periodically polls the AP configuration
to detect changes. When the AP configuration is dynamically changed via the
SE or an SCLP instruction, the changes will not be reflected to sysfs until
the next time the AP configuration is polled. The CHSC architecture
provides a Store Event Information (SEI) command to make notification of an
AP configuration change. This patch introduces a handler to process
notification from the CHSC SEI command by immediately kicking off an AP bus
scan-after-event.

Signed-off-by: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
Reviewed-by: Halil Pasic <pasic@xxxxxxxxxxxxx>
Reviewed-by: Sebastian Ott <sebott@xxxxxxxxxxxxx>
Reviewed-by: Harald Freudenberger <FREUDE@xxxxxxxxxx>
Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
---
 arch/s390/include/asm/ap.h   | 11 +++++++++++
 drivers/s390/cio/chsc.c      | 13 +++++++++++++
 drivers/s390/crypto/ap_bus.c | 10 ++++++++++
 3 files changed, 34 insertions(+)

diff --git a/arch/s390/include/asm/ap.h b/arch/s390/include/asm/ap.h
index 1a6a7092d942..e94a0a28b5eb 100644
--- a/arch/s390/include/asm/ap.h
+++ b/arch/s390/include/asm/ap.h
@@ -360,4 +360,15 @@ static inline struct ap_queue_status ap_dqap(ap_qid_t qid,
 	return reg1;
 }
 
+/*
+ * Interface to tell the AP bus code that a configuration
+ * change has happened. The bus code should at least do
+ * an ap bus resource rescan.
+ */
+#if IS_ENABLED(CONFIG_ZCRYPT)
+void ap_bus_cfg_chg(void);
+#else
+static inline void ap_bus_cfg_chg(void){};
+#endif
+
 #endif /* _ASM_S390_AP_H_ */
diff --git a/drivers/s390/cio/chsc.c b/drivers/s390/cio/chsc.c
index a0baee25134c..eaf4699be2c5 100644
--- a/drivers/s390/cio/chsc.c
+++ b/drivers/s390/cio/chsc.c
@@ -24,6 +24,7 @@
 #include <asm/crw.h>
 #include <asm/isc.h>
 #include <asm/ebcdic.h>
+#include <asm/ap.h>
 
 #include "css.h"
 #include "cio.h"
@@ -586,6 +587,15 @@ static void chsc_process_sei_scm_avail(struct chsc_sei_nt0_area *sei_area)
 			      " failed (rc=%d).\n", ret);
 }
 
+static void chsc_process_sei_ap_cfg_chg(struct chsc_sei_nt0_area *sei_area)
+{
+	CIO_CRW_EVENT(3, "chsc: ap config changed\n");
+	if (sei_area->rs != 5)
+		return;
+
+	ap_bus_cfg_chg();
+}
+
 static void chsc_process_sei_nt2(struct chsc_sei_nt2_area *sei_area)
 {
 	switch (sei_area->cc) {
@@ -612,6 +622,9 @@ static void chsc_process_sei_nt0(struct chsc_sei_nt0_area *sei_area)
 	case 2: /* i/o resource accessibility */
 		chsc_process_sei_res_acc(sei_area);
 		break;
+	case 3: /* ap config changed */
+		chsc_process_sei_ap_cfg_chg(sei_area);
+		break;
 	case 7: /* channel-path-availability information */
 		chsc_process_sei_chp_avail(sei_area);
 		break;
diff --git a/drivers/s390/crypto/ap_bus.c b/drivers/s390/crypto/ap_bus.c
index 5a699746c357..d0d415954142 100644
--- a/drivers/s390/crypto/ap_bus.c
+++ b/drivers/s390/crypto/ap_bus.c
@@ -861,6 +861,16 @@ void ap_bus_force_rescan(void)
 EXPORT_SYMBOL(ap_bus_force_rescan);
 
 /*
+* A config change has happened, force an ap bus rescan.
+*/
+void ap_bus_cfg_chg(void)
+{
+	AP_DBF(DBF_INFO, "%s config change, forcing bus rescan\n", __func__);
+
+	ap_bus_force_rescan();
+}
+
+/*
  * hex2bitmap() - parse hex mask string and set bitmap.
  * Valid strings are "0x012345678" with at least one valid hex number.
  * Rest of the bitmap to the right is padded with 0. No spaces allowed
-- 
2.7.4