[v12] Report vfio-ap configuration changes

[RFC PATCH v12 3/4] hw/vfio/ap: Storing event information for an AP configuration change event

Posted by Rorie Reyes 5 months, 1 week ago

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                 | 43 ++++++++++++++++++++++++++++++++++++
 include/hw/s390x/ap-bridge.h | 39 ++++++++++++++++++++++++++++++++
 2 files changed, 82 insertions(+)

diff --git a/hw/vfio/ap.c b/hw/vfio/ap.c
index fc435f5c5b..7e3c6278b3 100644
--- a/hw/vfio/ap.c
+++ b/hw/vfio/ap.c
@@ -10,6 +10,7 @@
  * directory.
  */
 
+#include <stdbool.h>
 #include "qemu/osdep.h"
 #include CONFIG_DEVICES /* CONFIG_IOMMUFD */
 #include <linux/vfio.h>
@@ -21,6 +22,7 @@
 #include "hw/s390x/css.h"
 #include "qemu/error-report.h"
 #include "qemu/event_notifier.h"
+#include "qemu/lockable.h"
 #include "qemu/main-loop.h"
 #include "qemu/module.h"
 #include "qemu/option.h"
@@ -48,6 +50,8 @@ typedef struct APConfigChgEvent {
 static QTAILQ_HEAD(, APConfigChgEvent) cfg_chg_events =
     QTAILQ_HEAD_INITIALIZER(cfg_chg_events);
 
+static QemuMutex cfg_chg_events_lock;
+
 OBJECT_DECLARE_SIMPLE_TYPE(VFIOAPDevice, VFIO_AP_DEVICE)
 
 static void vfio_ap_compute_needs_reset(VFIODevice *vdev)
@@ -96,6 +100,38 @@ static void vfio_ap_cfg_chg_notifier_handler(void *opaque)
 
 }
 
+int ap_chsc_sei_nt0_get_event(void *res)
+{
+    ChscSeiNt0Res *nt0_res  = (ChscSeiNt0Res *)res;
+    APConfigChgEvent *cfg_chg_event;
+
+    WITH_QEMU_LOCK_GUARD(&cfg_chg_events_lock) {
+        if (QTAILQ_EMPTY(&cfg_chg_events)) {
+            return EVENT_INFORMATION_NOT_STORED;
+        }
+
+        cfg_chg_event = QTAILQ_FIRST(&cfg_chg_events);
+        QTAILQ_REMOVE(&cfg_chg_events, cfg_chg_event, next);
+    }
+
+    memset(nt0_res, 0, sizeof(*nt0_res));
+    g_free(cfg_chg_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 EVENT_INFORMATION_STORED;
+}
+
+bool ap_chsc_sei_nt0_have_event(void)
+{
+    QEMU_LOCK_GUARD(&cfg_chg_events_lock);
+    return !QTAILQ_EMPTY(&cfg_chg_events);
+}
+
 static bool vfio_ap_register_irq_notifier(VFIOAPDevice *vapdev,
                                           unsigned int irq, Error **errp)
 {
@@ -192,6 +228,13 @@ static void vfio_ap_realize(DeviceState *dev, Error **errp)
     VFIOAPDevice *vapdev = VFIO_AP_DEVICE(dev);
     VFIODevice *vbasedev = &vapdev->vdev;
 
+    static bool lock_initialized;
+
+    if (!lock_initialized) {
+        qemu_mutex_init(&cfg_chg_events_lock);
+        lock_initialized = true;
+    }
+
     if (!vfio_device_get_name(vbasedev, errp)) {
         return;
     }
diff --git a/include/hw/s390x/ap-bridge.h b/include/hw/s390x/ap-bridge.h
index 470e439a98..7efc52928d 100644
--- a/include/hw/s390x/ap-bridge.h
+++ b/include/hw/s390x/ap-bridge.h
@@ -16,4 +16,43 @@
 
 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
+
+#define EVENT_INFORMATION_NOT_STORED 1
+#define EVENT_INFORMATION_STORED     0
+
+/**
+ * ap_chsc_sei_nt0_get_event - Retrieve the next pending AP config
+ * change event
+ * @res: Pointer to a ChscSeiNt0Res struct to be filled with event
+ * data
+ *
+ * This function checks for any pending AP config change events and,
+ * if present, populates the provided response structure with the
+ * appropriate SEI NT0 fields.
+ *
+ * Return:
+ *   EVENT_INFORMATION_STORED - An event was available and written to @res
+ *   EVENT_INFORMATION_NOT_STORED - No event was available
+ */
+int ap_chsc_sei_nt0_get_event(void *res);
+
+bool ap_chsc_sei_nt0_have_event(void);
+
 #endif
-- 
2.48.1

Re: [RFC PATCH v12 3/4] hw/vfio/ap: Storing event information for an AP configuration change event

Posted by Anthony Krowiak 5 months, 1 week ago



On 6/6/25 2:37 PM, Rorie Reyes wrote:
> 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>

Reviewed-by: Anthony Krowiak <akrowiak@linux.ibm.com>

> ---
>   hw/vfio/ap.c                 | 43 ++++++++++++++++++++++++++++++++++++
>   include/hw/s390x/ap-bridge.h | 39 ++++++++++++++++++++++++++++++++
>   2 files changed, 82 insertions(+)
>
> diff --git a/hw/vfio/ap.c b/hw/vfio/ap.c
> index fc435f5c5b..7e3c6278b3 100644
> --- a/hw/vfio/ap.c
> +++ b/hw/vfio/ap.c
> @@ -10,6 +10,7 @@
>    * directory.
>    */
>   
> +#include <stdbool.h>
>   #include "qemu/osdep.h"
>   #include CONFIG_DEVICES /* CONFIG_IOMMUFD */
>   #include <linux/vfio.h>
> @@ -21,6 +22,7 @@
>   #include "hw/s390x/css.h"
>   #include "qemu/error-report.h"
>   #include "qemu/event_notifier.h"
> +#include "qemu/lockable.h"
>   #include "qemu/main-loop.h"
>   #include "qemu/module.h"
>   #include "qemu/option.h"
> @@ -48,6 +50,8 @@ typedef struct APConfigChgEvent {
>   static QTAILQ_HEAD(, APConfigChgEvent) cfg_chg_events =
>       QTAILQ_HEAD_INITIALIZER(cfg_chg_events);
>   
> +static QemuMutex cfg_chg_events_lock;
> +
>   OBJECT_DECLARE_SIMPLE_TYPE(VFIOAPDevice, VFIO_AP_DEVICE)
>   
>   static void vfio_ap_compute_needs_reset(VFIODevice *vdev)
> @@ -96,6 +100,38 @@ static void vfio_ap_cfg_chg_notifier_handler(void *opaque)
>   
>   }
>   
> +int ap_chsc_sei_nt0_get_event(void *res)
> +{
> +    ChscSeiNt0Res *nt0_res  = (ChscSeiNt0Res *)res;
> +    APConfigChgEvent *cfg_chg_event;
> +
> +    WITH_QEMU_LOCK_GUARD(&cfg_chg_events_lock) {
> +        if (QTAILQ_EMPTY(&cfg_chg_events)) {
> +            return EVENT_INFORMATION_NOT_STORED;
> +        }
> +
> +        cfg_chg_event = QTAILQ_FIRST(&cfg_chg_events);
> +        QTAILQ_REMOVE(&cfg_chg_events, cfg_chg_event, next);
> +    }
> +
> +    memset(nt0_res, 0, sizeof(*nt0_res));
> +    g_free(cfg_chg_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 EVENT_INFORMATION_STORED;
> +}
> +
> +bool ap_chsc_sei_nt0_have_event(void)
> +{
> +    QEMU_LOCK_GUARD(&cfg_chg_events_lock);
> +    return !QTAILQ_EMPTY(&cfg_chg_events);
> +}
> +
>   static bool vfio_ap_register_irq_notifier(VFIOAPDevice *vapdev,
>                                             unsigned int irq, Error **errp)
>   {
> @@ -192,6 +228,13 @@ static void vfio_ap_realize(DeviceState *dev, Error **errp)
>       VFIOAPDevice *vapdev = VFIO_AP_DEVICE(dev);
>       VFIODevice *vbasedev = &vapdev->vdev;
>   
> +    static bool lock_initialized;
> +
> +    if (!lock_initialized) {
> +        qemu_mutex_init(&cfg_chg_events_lock);
> +        lock_initialized = true;
> +    }
> +
>       if (!vfio_device_get_name(vbasedev, errp)) {
>           return;
>       }
> diff --git a/include/hw/s390x/ap-bridge.h b/include/hw/s390x/ap-bridge.h
> index 470e439a98..7efc52928d 100644
> --- a/include/hw/s390x/ap-bridge.h
> +++ b/include/hw/s390x/ap-bridge.h
> @@ -16,4 +16,43 @@
>   
>   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
> +
> +#define EVENT_INFORMATION_NOT_STORED 1
> +#define EVENT_INFORMATION_STORED     0
> +
> +/**
> + * ap_chsc_sei_nt0_get_event - Retrieve the next pending AP config
> + * change event
> + * @res: Pointer to a ChscSeiNt0Res struct to be filled with event
> + * data
> + *
> + * This function checks for any pending AP config change events and,
> + * if present, populates the provided response structure with the
> + * appropriate SEI NT0 fields.
> + *
> + * Return:
> + *   EVENT_INFORMATION_STORED - An event was available and written to @res
> + *   EVENT_INFORMATION_NOT_STORED - No event was available
> + */
> +int ap_chsc_sei_nt0_get_event(void *res);
> +
> +bool ap_chsc_sei_nt0_have_event(void);
> +
>   #endif

[RFC PATCH v12 1/4] hw/vfio/ap: notification handler for AP config changed event
[RFC PATCH v12 2/4] hw/vfio/ap: store object indicating AP config changed in a queue
[RFC PATCH v12 3/4] hw/vfio/ap: Storing event information for an AP configuration change event
[RFC PATCH v12 4/4] s390: implementing CHSC SEI for AP config change