This is a note to let you know that I've just added the patch titled
vfio: Introduce interface to flush virqfd inject workqueue
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
vfio-introduce-interface-to-flush-virqfd-inject-workqueue.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From b620ecbd17a03cacd06f014a5d3f3a11285ce053 Mon Sep 17 00:00:00 2001
From: Alex Williamson <alex.williamson@xxxxxxxxxx>
Date: Fri, 8 Mar 2024 16:05:24 -0700
Subject: vfio: Introduce interface to flush virqfd inject workqueue
From: Alex Williamson <alex.williamson@xxxxxxxxxx>
commit b620ecbd17a03cacd06f014a5d3f3a11285ce053 upstream.
In order to synchronize changes that can affect the thread callback,
introduce an interface to force a flush of the inject workqueue. The
irqfd pointer is only valid under spinlock, but the workqueue cannot
be flushed under spinlock. Therefore the flush work for the irqfd is
queued under spinlock. The vfio_irqfd_cleanup_wq workqueue is re-used
for queuing this work such that flushing the workqueue is also ordered
relative to shutdown.
Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Reviewed-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240308230557.805580-4-alex.williamson@xxxxxxxxxx
Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
Stable-dep-of: 18c198c96a81 ("vfio/pci: Create persistent INTx handler")
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/vfio/virqfd.c | 21 +++++++++++++++++++++
include/linux/vfio.h | 2 ++
2 files changed, 23 insertions(+)
--- a/drivers/vfio/virqfd.c
+++ b/drivers/vfio/virqfd.c
@@ -101,6 +101,13 @@ static void virqfd_inject(struct work_st
virqfd->thread(virqfd->opaque, virqfd->data);
}
+static void virqfd_flush_inject(struct work_struct *work)
+{
+ struct virqfd *virqfd = container_of(work, struct virqfd, flush_inject);
+
+ flush_work(&virqfd->inject);
+}
+
int vfio_virqfd_enable(void *opaque,
int (*handler)(void *, void *),
void (*thread)(void *, void *),
@@ -124,6 +131,7 @@ int vfio_virqfd_enable(void *opaque,
INIT_WORK(&virqfd->shutdown, virqfd_shutdown);
INIT_WORK(&virqfd->inject, virqfd_inject);
+ INIT_WORK(&virqfd->flush_inject, virqfd_flush_inject);
irqfd = fdget(fd);
if (!irqfd.file) {
@@ -213,3 +221,16 @@ void vfio_virqfd_disable(struct virqfd *
flush_workqueue(vfio_irqfd_cleanup_wq);
}
EXPORT_SYMBOL_GPL(vfio_virqfd_disable);
+
+void vfio_virqfd_flush_thread(struct virqfd **pvirqfd)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&virqfd_lock, flags);
+ if (*pvirqfd && (*pvirqfd)->thread)
+ queue_work(vfio_irqfd_cleanup_wq, &(*pvirqfd)->flush_inject);
+ spin_unlock_irqrestore(&virqfd_lock, flags);
+
+ flush_workqueue(vfio_irqfd_cleanup_wq);
+}
+EXPORT_SYMBOL_GPL(vfio_virqfd_flush_thread);
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -349,6 +349,7 @@ struct virqfd {
wait_queue_entry_t wait;
poll_table pt;
struct work_struct shutdown;
+ struct work_struct flush_inject;
struct virqfd **pvirqfd;
};
@@ -356,5 +357,6 @@ int vfio_virqfd_enable(void *opaque, int
void (*thread)(void *, void *), void *data,
struct virqfd **pvirqfd, int fd);
void vfio_virqfd_disable(struct virqfd **pvirqfd);
+void vfio_virqfd_flush_thread(struct virqfd **pvirqfd);
#endif /* VFIO_H */
Patches currently in stable-queue which might be from alex.williamson@xxxxxxxxxx are
queue-6.6/vfio-pci-create-persistent-intx-handler.patch
queue-6.6/vfio-fsl-mc-block-calling-interrupt-handler-without-trigger.patch
queue-6.6/vfio-platform-disable-virqfds-on-cleanup.patch
queue-6.6/vfio-pci-disable-auto-enable-of-exclusive-intx-irq.patch
queue-6.6/vfio-pci-lock-external-intx-masking-ops.patch
queue-6.6/vfio-introduce-interface-to-flush-virqfd-inject-workqueue.patch
queue-6.6/vfio-pds-always-clear-the-save-restore-fds-on-reset.patch
queue-6.6/vfio-platform-create-persistent-irq-handlers.patch
