Series comparison

-[PATCH v1 0/5] Report vfio-ap configuration changes
+[RFC PATCH v3 0/5] Report vfio-ap configuration changes
+Changelog:
+v3:
+- changes that were made to patch 3/5 should have been made in
+patch 2/5
+v2:
+- removed warnings that weren't needed
+- added unregister function
+- removed whitelines
+- changed variable names for consistency
+- removed rc variable and returning 1 or 0 outright
+- reversed logics for if statements
+- using g_free() instead of free()
+- replaced hardcoded numeric values by defining them with #define
+in the header
+--------------------------------------------------------------------------
 This patch series creates and registers a handler that is called when
 userspace is notified by the kernel that a guest's AP configuration has
 changed. The handler in turn notifies the guest that its AP configuration
 has changed. This allows the guest to immediately respond to AP
 configuration changes rather than relying on polling or some other
 ...
   hw/vfio/ap: store object indicating AP config changed in a queue
   hw/vfio/ap: Storing event information for an AP configuration change
     event
   s390: implementing CHSC SEI for AP config change
- hw/vfio/ap.c                 | 74 ++++++++++++++++++++++++++++++++++++
+ hw/vfio/ap.c                 | 79 ++++++++++++++++++++++++++++++++++++
- include/hw/s390x/ap-bridge.h | 17 +++++++++
+ include/hw/s390x/ap-bridge.h | 22 ++++++++++
  linux-headers/linux/vfio.h   |  1 +
- target/s390x/ioinst.c        | 11 +++++-
+ target/s390x/ioinst.c        | 11 ++++-
-files changed, 101 insertions(+), 2 deletions(-)
+files changed, 111 insertions(+), 2 deletions(-)
 --
-.39.5 (Apple Git-154)
+.48.1

-[PATCH v1 1/5] linux-headers: NOTFORMERGE - placeholder uapi updates for AP config change
+[RFC PATCH v3 1/5] linux-headers: NOTFORMERGE - placeholder uapi updates for AP config change
 ...
 +    VFIO_AP_CFG_CHG_IRQ_INDEX,
      VFIO_AP_NUM_IRQS
  };
 --
-.39.5 (Apple Git-154)
+.48.1

-[PATCH v1 2/5] hw/vfio/ap: notification handler for AP config changed event
+[RFC PATCH v3 2/5] hw/vfio/ap: notification handler for AP config changed event
 Register an event notifier handler to process AP configuration
 change events by queuing the event and generating a CRW to let
 the guest know its AP configuration has changed
 Signed-off-by: Rorie Reyes <rreyes@linux.ibm.com>
-Reviewed-by: Anthony Krowiak <akrowiak@linux.ibm.com>
-Tested-by: Anthony Krowiak <akrowiak@linux.ibm.com>
 ---
- hw/vfio/ap.c | 27 +++++++++++++++++++++++++++
+ hw/vfio/ap.c | 31 +++++++++++++++++++++++++++++++
-file changed, 27 insertions(+)
+file changed, 31 insertions(+)
 diff --git a/hw/vfio/ap.c b/hw/vfio/ap.c
 index XXXXXXX..XXXXXXX 100644
 --- a/hw/vfio/ap.c
 +++ b/hw/vfio/ap.c
 ...
 +static void vfio_ap_cfg_chg_notifier_handler(void *opaque)
 +{
 +    VFIOAPDevice *vapdev = opaque;
 +
 +    if (!event_notifier_test_and_clear(&vapdev->cfg_notifier)) {
-+        warn_report("Event notifier not initialized");
 +        return;
 +    }
 +
 +    css_generate_css_crws(0);
++
 +}
 +
  static bool vfio_ap_register_irq_notifier(VFIOAPDevice *vapdev,
                                            unsigned int irq, Error **errp)
  {
 ...
 +        fd_read = vfio_ap_cfg_chg_notifier_handler;
 +        break;
      default:
          error_setg(errp, "vfio: Unsupported device irq(%d)", irq);
          return false;
+@@ -XXX,XX +XXX,XX @@ static void vfio_ap_unregister_irq_notifier(VFIOAPDevice *vapdev,
+     case VFIO_AP_REQ_IRQ_INDEX:
+         notifier = &vapdev->req_notifier;
+         break;
++    case VFIO_AP_CFG_CHG_IRQ_INDEX:
++        notifier = &vapdev->cfg_notifier;
++        break;
+     default:
+         error_report("vfio: Unsupported device irq(%d)", irq);
+         return;
 @@ -XXX,XX +XXX,XX @@ static void vfio_ap_realize(DeviceState *dev, Error **errp)
          warn_report_err(err);
      }
 +    if (!vfio_ap_register_irq_notifier(vapdev, VFIO_AP_CFG_CHG_IRQ_INDEX, &err))
 ...
 +    }
 +
      return;
  error:
+@@ -XXX,XX +XXX,XX @@ static void vfio_ap_unrealize(DeviceState *dev)
+     VFIOAPDevice *vapdev = VFIO_AP_DEVICE(dev);
+     vfio_ap_unregister_irq_notifier(vapdev, VFIO_AP_REQ_IRQ_INDEX);
++    vfio_ap_unregister_irq_notifier(vapdev, VFIO_AP_CFG_CHG_IRQ_INDEX);
+     vfio_detach_device(&vapdev->vdev);
+     g_free(vapdev->vdev.name);
+ }
 --
-.39.5 (Apple Git-154)
+.48.1

-[PATCH v1 3/5] hw/vfio/ap: store object indicating AP config changed in a queue
+[RFC PATCH v3 3/5] hw/vfio/ap: store object indicating AP config changed in a queue
 Creates an object indicating that an AP configuration change event
 has been received and stores it in a queue. These objects will later
 be used to store event information for an AP configuration change
 when the CHSC instruction is intercepted.
 Signed-off-by: Rorie Reyes <rreyes@linux.ibm.com>
-Reviewed-by: Anthony Krowiak <akrowiak@linux.ibm.com>
-Tested-by: Anthony Krowiak <akrowiak@linux.ibm.com>
 ---
  hw/vfio/ap.c | 10 ++++++++++
 file changed, 10 insertions(+)
 diff --git a/hw/vfio/ap.c b/hw/vfio/ap.c
 ...
 +    QTAILQ_HEAD_INITIALIZER(cfg_chg_events);
 +
  OBJECT_DECLARE_SIMPLE_TYPE(VFIOAPDevice, VFIO_AP_DEVICE)
  static void vfio_ap_compute_needs_reset(VFIODevice *vdev)
-@@ -XXX,XX +XXX,XX @@ static void vfio_ap_cfg_chg_notifier_handler(void *opaque)
+@@ -XXX,XX +XXX,XX @@ static void vfio_ap_req_notifier_handler(void *opaque)
  static void vfio_ap_cfg_chg_notifier_handler(void *opaque)
  {
      VFIOAPDevice *vapdev = opaque;
++    APConfigChgEvent *cfg_chg_event = g_new0(APConfigChgEvent, 1);
-+    APConfigChgEvent *new_event = g_new0(APConfigChgEvent, 1);
      if (!event_notifier_test_and_clear(&vapdev->cfg_notifier)) {
          return;
      }
 +    QTAILQ_INSERT_TAIL(&cfg_chg_events, cfg_chg_event, next);
 +
-+    QTAILQ_INSERT_TAIL(&cfg_chg_events, new_event, next);
+     css_generate_css_crws(0);
-     if (!event_notifier_test_and_clear(&vapdev->cfg_notifier)) {
-         warn_report("Event notifier not initialized");
+ }
          return;
 --
-.39.5 (Apple Git-154)
+.48.1

-[PATCH v1 4/5] hw/vfio/ap: Storing event information for an AP configuration change event
+[RFC PATCH v3 4/5] hw/vfio/ap: Storing event information for an AP configuration change event
 These functions can be invoked by the function that handles interception
 of the CHSC SEI instruction for requests indicating the accessibility of
 one or more adjunct processors has changed.
 Signed-off-by: Rorie Reyes <rreyes@linux.ibm.com>
 ---
- hw/vfio/ap.c                 | 37 ++++++++++++++++++++++++++++++++++++
+ hw/vfio/ap.c                 | 38 ++++++++++++++++++++++++++++++++++++
- include/hw/s390x/ap-bridge.h | 17 +++++++++++++++++
+ include/hw/s390x/ap-bridge.h | 22 +++++++++++++++++++++
-files changed, 54 insertions(+)
+files changed, 60 insertions(+)
 diff --git a/hw/vfio/ap.c b/hw/vfio/ap.c
 index XXXXXXX..XXXXXXX 100644
 --- a/hw/vfio/ap.c
 +++ b/hw/vfio/ap.c
 @@ -XXX,XX +XXX,XX @@ static void vfio_ap_cfg_chg_notifier_handler(void *opaque)
-     css_generate_css_crws(0);
  }
 +int ap_chsc_sei_nt0_get_event(void *res)
 +{
 +    APConfigChgEvent *cfg_chg_event = QTAILQ_FIRST(&cfg_chg_events);
 +    ChscSeiNt0Res *nt0_res  = (ChscSeiNt0Res *)res;
++
 +    memset(nt0_res, 0, sizeof(*nt0_res));
-+    int rc = 1;
 +
-+    if (cfg_chg_event) {
++    if (!cfg_chg_event) {
-+        QTAILQ_REMOVE(&cfg_chg_events, cfg_chg_event, next);
++        return 1;
 +        free(cfg_chg_event);
 +
 +        /*
 +         * If there are any AP configuration change events in the queue,
 +         * indicate to the caller that there is pending event info in
 +         * the response block
 +         */
 +        if (!QTAILQ_EMPTY(&cfg_chg_events)) {
 +            nt0_res->flags |= PENDING_EVENT_INFO_BITMASK;
 +        }
 +
 +        nt0_res->length = sizeof(ChscSeiNt0Res);
 +        nt0_res->code = 1;
 +        nt0_res->nt = 0;
 +        nt0_res->rs = 5;
 +        nt0_res->cc = 3;
 +
 +        rc = 0;
 +    }
 +
-+    return rc;
++    QTAILQ_REMOVE(&cfg_chg_events, cfg_chg_event, next);
 +    g_free(cfg_chg_event);
 +
 +    /*
 +     * If there are any AP configuration change events in the queue,
 +     * indicate to the caller that there is pending event info in
 +     * the response block
 +     */
 +    if (ap_chsc_sei_nt0_have_event()) {
 +        nt0_res->flags |= PENDING_EVENT_INFO_BITMASK;
 +    }
 +
 +    nt0_res->length = sizeof(ChscSeiNt0Res);
 +    nt0_res->code = NT0_RES_RESPONSE_CODE;
 +    nt0_res->nt = NT0_RES_NT_DEFAULT;
 +    nt0_res->rs = NT0_RES_RS_AP_CHANGE;
 +    nt0_res->cc = NT0_RES_CC_AP_CHANGE;
 +
 +    return 0;
 +
 +}
 +
 +int ap_chsc_sei_nt0_have_event(void)
 +{
 +    return !QTAILQ_EMPTY(&cfg_chg_events);
 ...
 +    uint8_t reserved3;
 +    uint8_t rs;
 +    uint8_t cc;
 +} QEMU_PACKED ChscSeiNt0Res;
 +
++#define NT0_RES_RESPONSE_CODE 1;
++#define NT0_RES_NT_DEFAULT    0;
++#define NT0_RES_RS_AP_CHANGE  5;
++#define NT0_RES_CC_AP_CHANGE  3;
++
 +int ap_chsc_sei_nt0_get_event(void *res);
 +
 +int ap_chsc_sei_nt0_have_event(void);
 +
  #endif
 --
-.39.5 (Apple Git-154)
+.48.1

-[PATCH v1 5/5] s390: implementing CHSC SEI for AP config change
+[RFC PATCH v3 5/5] s390: implementing CHSC SEI for AP config change
 ...
 +
      return 0;
  }
 --
-.39.5 (Apple Git-154)
+.48.1

This patch series creates and registers a handler that is called when
userspace is notified by the kernel that a guest's AP configuration has
changed. The handler in turn notifies the guest that its AP configuration
has changed. This allows the guest to immediately respond to AP
configuration changes rather than relying on polling or some other
inefficient mechanism for detecting config changes.

Rorie Reyes (5):
  linux-headers: NOTFORMERGE - placeholder uapi updates for AP config
    change
  hw/vfio/ap: notification handler for AP config changed event
  hw/vfio/ap: store object indicating AP config changed in a queue
  hw/vfio/ap: Storing event information for an AP configuration change
    event
  s390: implementing CHSC SEI for AP config change

hw/vfio/ap.c                 | 74 ++++++++++++++++++++++++++++++++++++
 include/hw/s390x/ap-bridge.h | 17 +++++++++
 linux-headers/linux/vfio.h   |  1 +
 target/s390x/ioinst.c        | 11 +++++-
 4 files changed, 101 insertions(+), 2 deletions(-)

-- 
2.39.5 (Apple Git-154)

Register an event notifier handler to process AP configuration
change events by queuing the event and generating a CRW to let
the guest know its AP configuration has changed

Signed-off-by: Rorie Reyes <rreyes@linux.ibm.com>
Reviewed-by: Anthony Krowiak <akrowiak@linux.ibm.com>
Tested-by: Anthony Krowiak <akrowiak@linux.ibm.com>
---
 hw/vfio/ap.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/hw/vfio/ap.c b/hw/vfio/ap.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/vfio/ap.c
+++ b/hw/vfio/ap.c
@@ -XXX,XX +XXX,XX @@
 #include "hw/vfio/vfio-common.h"
 #include "system/iommufd.h"
 #include "hw/s390x/ap-device.h"
+#include "hw/s390x/css.h"
 #include "qemu/error-report.h"
 #include "qemu/event_notifier.h"
 #include "qemu/main-loop.h"
@@ -XXX,XX +XXX,XX @@ struct VFIOAPDevice {
     APDevice apdev;
     VFIODevice vdev;
     EventNotifier req_notifier;
+    EventNotifier cfg_notifier;
 };
 
 OBJECT_DECLARE_SIMPLE_TYPE(VFIOAPDevice, VFIO_AP_DEVICE)
@@ -XXX,XX +XXX,XX @@ static void vfio_ap_req_notifier_handler(void *opaque)
     }
 }
 
+static void vfio_ap_cfg_chg_notifier_handler(void *opaque)
+{
+    VFIOAPDevice *vapdev = opaque;
+
+    if (!event_notifier_test_and_clear(&vapdev->cfg_notifier)) {
+        warn_report("Event notifier not initialized");
+        return;
+    }
+
+    css_generate_css_crws(0);
+}
+
 static bool vfio_ap_register_irq_notifier(VFIOAPDevice *vapdev,
                                           unsigned int irq, Error **errp)
 {
@@ -XXX,XX +XXX,XX @@ static bool vfio_ap_register_irq_notifier(VFIOAPDevice *vapdev,
         notifier = &vapdev->req_notifier;
         fd_read = vfio_ap_req_notifier_handler;
         break;
+    case VFIO_AP_CFG_CHG_IRQ_INDEX:
+        notifier = &vapdev->cfg_notifier;
+        fd_read = vfio_ap_cfg_chg_notifier_handler;
+        break;
     default:
         error_setg(errp, "vfio: Unsupported device irq(%d)", irq);
         return false;
@@ -XXX,XX +XXX,XX @@ static void vfio_ap_realize(DeviceState *dev, Error **errp)
         warn_report_err(err);
     }
 
+    if (!vfio_ap_register_irq_notifier(vapdev, VFIO_AP_CFG_CHG_IRQ_INDEX, &err))
+    {
+        /*
+         * Report this error, but do not make it a failing condition.
+         * Lack of this IRQ in the host does not prevent normal operation.
+         */
+        warn_report_err(err);
+    }
+
     return;
 
 error:
-- 
2.39.5 (Apple Git-154)

Creates an object indicating that an AP configuration change event
has been received and stores it in a queue. These objects will later
be used to store event information for an AP configuration change
when the CHSC instruction is intercepted.

diff --git a/hw/vfio/ap.c b/hw/vfio/ap.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/vfio/ap.c
+++ b/hw/vfio/ap.c
@@ -XXX,XX +XXX,XX @@ struct VFIOAPDevice {
     EventNotifier cfg_notifier;
 };
 
+typedef struct APConfigChgEvent {
+    QTAILQ_ENTRY(APConfigChgEvent) next;
+} APConfigChgEvent;
+
+QTAILQ_HEAD(, APConfigChgEvent) cfg_chg_events =
+    QTAILQ_HEAD_INITIALIZER(cfg_chg_events);
+
 OBJECT_DECLARE_SIMPLE_TYPE(VFIOAPDevice, VFIO_AP_DEVICE)
 
 static void vfio_ap_compute_needs_reset(VFIODevice *vdev)
@@ -XXX,XX +XXX,XX @@ static void vfio_ap_cfg_chg_notifier_handler(void *opaque)
 {
     VFIOAPDevice *vapdev = opaque;
 
+    APConfigChgEvent *new_event = g_new0(APConfigChgEvent, 1);
+
+    QTAILQ_INSERT_TAIL(&cfg_chg_events, new_event, next);
     if (!event_notifier_test_and_clear(&vapdev->cfg_notifier)) {
         warn_report("Event notifier not initialized");
         return;
-- 
2.39.5 (Apple Git-154)

These functions can be invoked by the function that handles interception
of the CHSC SEI instruction for requests indicating the accessibility of
one or more adjunct processors has changed.

Signed-off-by: Rorie Reyes <rreyes@linux.ibm.com>
---
 hw/vfio/ap.c                 | 37 ++++++++++++++++++++++++++++++++++++
 include/hw/s390x/ap-bridge.h | 17 +++++++++++++++++
 2 files changed, 54 insertions(+)

diff --git a/hw/vfio/ap.c b/hw/vfio/ap.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/vfio/ap.c
+++ b/hw/vfio/ap.c
@@ -XXX,XX +XXX,XX @@ static void vfio_ap_cfg_chg_notifier_handler(void *opaque)
     css_generate_css_crws(0);
 }
 
+int ap_chsc_sei_nt0_get_event(void *res)
+{
+    APConfigChgEvent *cfg_chg_event = QTAILQ_FIRST(&cfg_chg_events);
+    ChscSeiNt0Res *nt0_res  = (ChscSeiNt0Res *)res;
+    memset(nt0_res, 0, sizeof(*nt0_res));
+    int rc = 1;
+
+    if (cfg_chg_event) {
+        QTAILQ_REMOVE(&cfg_chg_events, cfg_chg_event, next);
+        free(cfg_chg_event);
+
+        /*
+         * If there are any AP configuration change events in the queue,
+         * indicate to the caller that there is pending event info in
+         * the response block
+         */
+        if (!QTAILQ_EMPTY(&cfg_chg_events)) {
+            nt0_res->flags |= PENDING_EVENT_INFO_BITMASK;
+        }
+
+        nt0_res->length = sizeof(ChscSeiNt0Res);
+        nt0_res->code = 1;
+        nt0_res->nt = 0;
+        nt0_res->rs = 5;
+        nt0_res->cc = 3;
+
+        rc = 0;
+    }
+
+    return rc;
+}
+
+int ap_chsc_sei_nt0_have_event(void)
+{
+    return !QTAILQ_EMPTY(&cfg_chg_events);
+}
+
 static bool vfio_ap_register_irq_notifier(VFIOAPDevice *vapdev,
                                           unsigned int irq, Error **errp)
 {
diff --git a/include/hw/s390x/ap-bridge.h b/include/hw/s390x/ap-bridge.h
index XXXXXXX..XXXXXXX 100644
--- a/include/hw/s390x/ap-bridge.h
+++ b/include/hw/s390x/ap-bridge.h
@@ -XXX,XX +XXX,XX @@
 
 void s390_init_ap(void);
 
+typedef struct ChscSeiNt0Res {
+    uint16_t length;
+    uint16_t code;
+    uint8_t reserved1;
+    uint16_t reserved2;
+    uint8_t nt;
+#define PENDING_EVENT_INFO_BITMASK 0x80;
+    uint8_t flags;
+    uint8_t reserved3;
+    uint8_t rs;
+    uint8_t cc;
+} QEMU_PACKED ChscSeiNt0Res;
+
+int ap_chsc_sei_nt0_get_event(void *res);
+
+int ap_chsc_sei_nt0_have_event(void);
+
 #endif
-- 
2.39.5 (Apple Git-154)

Handle interception of the CHSC SEI instruction for requests
indicating the guest's AP configuration has changed.

Signed-off-by: Rorie Reyes <rreyes@linux.ibm.com>
Reviewed-by: Anthony Krowiak <akrowiak@linux.ibm.com>
Tested-by: Anthony Krowiak <akrowiak@linux.ibm.com>
---
 target/s390x/ioinst.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/target/s390x/ioinst.c b/target/s390x/ioinst.c
index XXXXXXX..XXXXXXX 100644
--- a/target/s390x/ioinst.c
+++ b/target/s390x/ioinst.c
@@ -XXX,XX +XXX,XX @@
 #include "trace.h"
 #include "hw/s390x/s390-pci-bus.h"
 #include "target/s390x/kvm/pv.h"
+#include "hw/s390x/ap-bridge.h"
 
 /* All I/O instructions but chsc use the s format */
 static uint64_t get_address_from_regs(CPUS390XState *env, uint32_t ipb,
@@ -XXX,XX +XXX,XX @@ out:
 
 static int chsc_sei_nt0_get_event(void *res)
 {
-    /* no events yet */
+    if (s390_has_feat(S390_FEAT_AP)) {
+        return ap_chsc_sei_nt0_get_event(res);
+    }
+
     return 1;
 }
 
 static int chsc_sei_nt0_have_event(void)
 {
-    /* no events yet */
+    if (s390_has_feat(S390_FEAT_AP)) {
+        return ap_chsc_sei_nt0_have_event();
+    }
+
     return 0;
 }
 
-- 
2.39.5 (Apple Git-154)

Changelog:

v3:
- changes that were made to patch 3/5 should have been made in
patch 2/5

v2:
- removed warnings that weren't needed
- added unregister function
- removed whitelines
- changed variable names for consistency
- removed rc variable and returning 1 or 0 outright
- reversed logics for if statements
- using g_free() instead of free()
- replaced hardcoded numeric values by defining them with #define
in the header

--------------------------------------------------------------------------
This patch series creates and registers a handler that is called when
userspace is notified by the kernel that a guest's AP configuration has
changed. The handler in turn notifies the guest that its AP configuration
has changed. This allows the guest to immediately respond to AP
configuration changes rather than relying on polling or some other
inefficient mechanism for detecting config changes.

hw/vfio/ap.c                 | 79 ++++++++++++++++++++++++++++++++++++
 include/hw/s390x/ap-bridge.h | 22 ++++++++++
 linux-headers/linux/vfio.h   |  1 +
 target/s390x/ioinst.c        | 11 ++++-
 4 files changed, 111 insertions(+), 2 deletions(-)

-- 
2.48.1

Register an event notifier handler to process AP configuration
change events by queuing the event and generating a CRW to let
the guest know its AP configuration has changed

Signed-off-by: Rorie Reyes <rreyes@linux.ibm.com>
---
 hw/vfio/ap.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/hw/vfio/ap.c b/hw/vfio/ap.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/vfio/ap.c
+++ b/hw/vfio/ap.c
@@ -XXX,XX +XXX,XX @@
 #include "hw/vfio/vfio-common.h"
 #include "system/iommufd.h"
 #include "hw/s390x/ap-device.h"
+#include "hw/s390x/css.h"
 #include "qemu/error-report.h"
 #include "qemu/event_notifier.h"
 #include "qemu/main-loop.h"
@@ -XXX,XX +XXX,XX @@ struct VFIOAPDevice {
     APDevice apdev;
     VFIODevice vdev;
     EventNotifier req_notifier;
+    EventNotifier cfg_notifier;
 };
 
 OBJECT_DECLARE_SIMPLE_TYPE(VFIOAPDevice, VFIO_AP_DEVICE)
@@ -XXX,XX +XXX,XX @@ static void vfio_ap_req_notifier_handler(void *opaque)
     }
 }
 
+static void vfio_ap_cfg_chg_notifier_handler(void *opaque)
+{
+    VFIOAPDevice *vapdev = opaque;
+
+    if (!event_notifier_test_and_clear(&vapdev->cfg_notifier)) {
+        return;
+    }
+
+    css_generate_css_crws(0);
+
+}
+
 static bool vfio_ap_register_irq_notifier(VFIOAPDevice *vapdev,
                                           unsigned int irq, Error **errp)
 {
@@ -XXX,XX +XXX,XX @@ static bool vfio_ap_register_irq_notifier(VFIOAPDevice *vapdev,
         notifier = &vapdev->req_notifier;
         fd_read = vfio_ap_req_notifier_handler;
         break;
+    case VFIO_AP_CFG_CHG_IRQ_INDEX:
+        notifier = &vapdev->cfg_notifier;
+        fd_read = vfio_ap_cfg_chg_notifier_handler;
+        break;
     default:
         error_setg(errp, "vfio: Unsupported device irq(%d)", irq);
         return false;
@@ -XXX,XX +XXX,XX @@ static void vfio_ap_unregister_irq_notifier(VFIOAPDevice *vapdev,
     case VFIO_AP_REQ_IRQ_INDEX:
         notifier = &vapdev->req_notifier;
         break;
+    case VFIO_AP_CFG_CHG_IRQ_INDEX:
+        notifier = &vapdev->cfg_notifier;
+        break;
     default:
         error_report("vfio: Unsupported device irq(%d)", irq);
         return;
@@ -XXX,XX +XXX,XX @@ static void vfio_ap_realize(DeviceState *dev, Error **errp)
         warn_report_err(err);
     }
 
+    if (!vfio_ap_register_irq_notifier(vapdev, VFIO_AP_CFG_CHG_IRQ_INDEX, &err))
+    {
+        /*
+         * Report this error, but do not make it a failing condition.
+         * Lack of this IRQ in the host does not prevent normal operation.
+         */
+        warn_report_err(err);
+    }
+
     return;
 
 error:
@@ -XXX,XX +XXX,XX @@ static void vfio_ap_unrealize(DeviceState *dev)
     VFIOAPDevice *vapdev = VFIO_AP_DEVICE(dev);
 
     vfio_ap_unregister_irq_notifier(vapdev, VFIO_AP_REQ_IRQ_INDEX);
+    vfio_ap_unregister_irq_notifier(vapdev, VFIO_AP_CFG_CHG_IRQ_INDEX);
     vfio_detach_device(&vapdev->vdev);
     g_free(vapdev->vdev.name);
 }
-- 
2.48.1

Signed-off-by: Rorie Reyes <rreyes@linux.ibm.com>
---
 hw/vfio/ap.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/hw/vfio/ap.c b/hw/vfio/ap.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/vfio/ap.c
+++ b/hw/vfio/ap.c
@@ -XXX,XX +XXX,XX @@ struct VFIOAPDevice {
     EventNotifier cfg_notifier;
 };
 
+typedef struct APConfigChgEvent {
+    QTAILQ_ENTRY(APConfigChgEvent) next;
+} APConfigChgEvent;
+
+QTAILQ_HEAD(, APConfigChgEvent) cfg_chg_events =
+    QTAILQ_HEAD_INITIALIZER(cfg_chg_events);
+
 OBJECT_DECLARE_SIMPLE_TYPE(VFIOAPDevice, VFIO_AP_DEVICE)
 
 static void vfio_ap_compute_needs_reset(VFIODevice *vdev)
@@ -XXX,XX +XXX,XX @@ static void vfio_ap_req_notifier_handler(void *opaque)
 static void vfio_ap_cfg_chg_notifier_handler(void *opaque)
 {
     VFIOAPDevice *vapdev = opaque;
+    APConfigChgEvent *cfg_chg_event = g_new0(APConfigChgEvent, 1);
 
     if (!event_notifier_test_and_clear(&vapdev->cfg_notifier)) {
         return;
     }
 
+    QTAILQ_INSERT_TAIL(&cfg_chg_events, cfg_chg_event, next);
+
     css_generate_css_crws(0);
 
 }
-- 
2.48.1

These functions can be invoked by the function that handles interception
of the CHSC SEI instruction for requests indicating the accessibility of
one or more adjunct processors has changed.

Signed-off-by: Rorie Reyes <rreyes@linux.ibm.com>
---
 hw/vfio/ap.c                 | 38 ++++++++++++++++++++++++++++++++++++
 include/hw/s390x/ap-bridge.h | 22 +++++++++++++++++++++
 2 files changed, 60 insertions(+)

diff --git a/hw/vfio/ap.c b/hw/vfio/ap.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/vfio/ap.c
+++ b/hw/vfio/ap.c
@@ -XXX,XX +XXX,XX @@ static void vfio_ap_cfg_chg_notifier_handler(void *opaque)
 
 }
 
+int ap_chsc_sei_nt0_get_event(void *res)
+{
+    APConfigChgEvent *cfg_chg_event = QTAILQ_FIRST(&cfg_chg_events);
+    ChscSeiNt0Res *nt0_res  = (ChscSeiNt0Res *)res;
+
+    memset(nt0_res, 0, sizeof(*nt0_res));
+
+    if (!cfg_chg_event) {
+        return 1;
+    }
+
+    QTAILQ_REMOVE(&cfg_chg_events, cfg_chg_event, next);
+    g_free(cfg_chg_event);
+
+    /*
+     * If there are any AP configuration change events in the queue,
+     * indicate to the caller that there is pending event info in
+     * the response block
+     */
+    if (ap_chsc_sei_nt0_have_event()) {
+        nt0_res->flags |= PENDING_EVENT_INFO_BITMASK;
+    }
+
+    nt0_res->length = sizeof(ChscSeiNt0Res);
+    nt0_res->code = NT0_RES_RESPONSE_CODE;
+    nt0_res->nt = NT0_RES_NT_DEFAULT;
+    nt0_res->rs = NT0_RES_RS_AP_CHANGE;
+    nt0_res->cc = NT0_RES_CC_AP_CHANGE;
+
+    return 0;
+
+}
+
+int ap_chsc_sei_nt0_have_event(void)
+{
+    return !QTAILQ_EMPTY(&cfg_chg_events);
+}
+
 static bool vfio_ap_register_irq_notifier(VFIOAPDevice *vapdev,
                                           unsigned int irq, Error **errp)
 {
diff --git a/include/hw/s390x/ap-bridge.h b/include/hw/s390x/ap-bridge.h
index XXXXXXX..XXXXXXX 100644
--- a/include/hw/s390x/ap-bridge.h
+++ b/include/hw/s390x/ap-bridge.h
@@ -XXX,XX +XXX,XX @@
 
 void s390_init_ap(void);
 
+typedef struct ChscSeiNt0Res {
+    uint16_t length;
+    uint16_t code;
+    uint8_t reserved1;
+    uint16_t reserved2;
+    uint8_t nt;
+#define PENDING_EVENT_INFO_BITMASK 0x80;
+    uint8_t flags;
+    uint8_t reserved3;
+    uint8_t rs;
+    uint8_t cc;
+} QEMU_PACKED ChscSeiNt0Res;
+
+#define NT0_RES_RESPONSE_CODE 1;
+#define NT0_RES_NT_DEFAULT    0;
+#define NT0_RES_RS_AP_CHANGE  5;
+#define NT0_RES_CC_AP_CHANGE  3;
+
+int ap_chsc_sei_nt0_get_event(void *res);
+
+int ap_chsc_sei_nt0_have_event(void);
+
 #endif
-- 
2.48.1

Handle interception of the CHSC SEI instruction for requests
indicating the guest's AP configuration has changed.