On 6/4/25 9:47 AM, Anthony Krowiak wrote:
On 6/3/25 4:30 PM, Cédric Le Goater wrote:
On 6/3/25 20:01, Rorie Reyes wrote:
On 6/3/25 10:21 AM, Cédric Le Goater wrote:
On 6/3/25 14:58, Rorie Reyes wrote:
Hey Cedric,
You mentioned the following in my v9 patches
"In that case, let's keep it simple (no mutex) and add a
assert(bql_locked())
statement where we think the bql should be protecting access to
shared
resources. "
Does this still apply down bellow?
Anthony replied :
https://lore.kernel.org/qemu-devel/ed2a2aa3-68a7-480c-a6a4-a8219af12...@linux.ibm.com/
Thanks,
C.
So we'll still use WITH_QEMU_LOCK_GUARD?
If a lock is needed to protect the list, then
ap_chsc_sei_nt0_have_event()
should lock/unlock too. WITH_QEMU_LOCK_GUARD() is just a pratical way to
do so.
Since ap_chsc_sei_nt0_have_event() is a single line that returns
!QTAILQ_EMPTY(&cfg_chg_events), wouldn't it be better to just
use the QEMU_LOCK_GUARD macro which, if I'm not mistaken,
will unlock on the return statement?
Thanks,
C.
On 5/26/25 4:40 AM, Cédric Le Goater wrote:
On 5/23/25 18:03, 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 <rre...@linux.ibm.com>
---
hw/vfio/ap.c | 53
++++++++++++++++++++++++++++++++++++
include/hw/s390x/ap-bridge.h | 39 ++++++++++++++++++++++++++
2 files changed, 92 insertions(+)
diff --git a/hw/vfio/ap.c b/hw/vfio/ap.c
index fc435f5c5b..97a42a575a 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>
@@ -48,6 +49,8 @@ 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 +99,49 @@ 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;
+
+ qemu_mutex_lock(&cfg_chg_events_lock);
please consider using WITH_QEMU_LOCK_GUARD()
See note above about bql_locked
+ if (!ap_chsc_sei_nt0_have_event()) {
+ qemu_mutex_unlock(&cfg_chg_events_lock);
+ return EVENT_INFORMATION_NOT_STORED;
+ }
+
+ cfg_chg_event = QTAILQ_FIRST(&cfg_chg_events);
+ QTAILQ_REMOVE(&cfg_chg_events, cfg_chg_event, next);
+
+ qemu_mutex_unlock(&cfg_chg_events_lock);
+
+ memset(nt0_res, 0, sizeof(*nt0_res));
+ 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 EVENT_INFORMATION_STORED;
+}
+
+bool ap_chsc_sei_nt0_have_event(void)
hmm, no locking ?
How important do we need to lock this? When I lock this method my guest
freezes every time. But when I only lock the get event, my code
continues to work as designed
See not above for bql_locked
+{
+ return !QTAILQ_EMPTY(&cfg_chg_events);
+}
+
static bool vfio_ap_register_irq_notifier(VFIOAPDevice *vapdev,
unsigned int irq,
Error **errp)
