[PATCH v14 18/20] vfio: move eventfd support code for VFIO_PCI to a separate file

Baptiste Reynal
2015-03-02T16:59:58Z

From: Antonios Motakis <a.motakis-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J@public.gmane.org>

The virqfd functionality that is used by VFIO_PCI to implement interrupt
masking and unmasking via an eventfd, is generic enough and can be reused
by another driver. Move it to a separate file in order to allow the code
to be shared.

Signed-off-by: Antonios Motakis <a.motakis-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J@public.gmane.org>
Signed-off-by: Baptiste Reynal <b.reynal-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J@public.gmane.org>
---
drivers/vfio/pci/Makefile | 3 +-
drivers/vfio/pci/vfio_pci_intrs.c | 215 ------------------------------------
drivers/vfio/pci/vfio_pci_private.h | 3 -
drivers/vfio/virqfd.c | 213 +++++++++++++++++++++++++++++++++++
include/linux/vfio.h | 27 +++++
5 files changed, 242 insertions(+), 219 deletions(-)
create mode 100644 drivers/vfio/virqfd.c

diff --git a/drivers/vfio/pci/Makefile b/drivers/vfio/pci/Makefile
index 1310792..c7c8644 100644
--- a/drivers/vfio/pci/Makefile
+++ b/drivers/vfio/pci/Makefile
@@ -1,4 +1,5 @@

-vfio-pci-y := vfio_pci.o vfio_pci_intrs.o vfio_pci_rdwr.o vfio_pci_config.o
+vfio-pci-y := vfio_pci.o vfio_pci_intrs.o vfio_pci_rdwr.o vfio_pci_config.o \
+ ../virqfd.o

obj-$(CONFIG_VFIO_PCI) += vfio-pci.o
diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
index 1a16da3..da6616e 100644
--- a/drivers/vfio/pci/vfio_pci_intrs.c
+++ b/drivers/vfio/pci/vfio_pci_intrs.c
@@ -19,228 +19,13 @@
#include <linux/msi.h>
#include <linux/pci.h>
#include <linux/file.h>
-#include <linux/poll.h>
#include <linux/vfio.h>
#include <linux/wait.h>
-#include <linux/workqueue.h>
#include <linux/slab.h>

#include "vfio_pci_private.h"

/*
- * IRQfd - generic
- */
-struct virqfd {
- void *opaque;
- struct eventfd_ctx *eventfd;
- int (*handler)(void *, void *);
- void (*thread)(void *, void *);
- void *data;
- struct work_struct inject;
- wait_queue_t wait;
- poll_table pt;
- struct work_struct shutdown;
- struct virqfd **pvirqfd;
-};
-
-static struct workqueue_struct *vfio_irqfd_cleanup_wq;
-DEFINE_SPINLOCK(virqfd_lock);
-
-int __init vfio_virqfd_init(void)
-{
- vfio_irqfd_cleanup_wq =
- create_singlethread_workqueue("vfio-irqfd-cleanup");
- if (!vfio_irqfd_cleanup_wq)
- return -ENOMEM;
-
- return 0;
-}
-
-void vfio_virqfd_exit(void)
-{
- destroy_workqueue(vfio_irqfd_cleanup_wq);
-}
-
-static void virqfd_deactivate(struct virqfd *virqfd)
-{
- queue_work(vfio_irqfd_cleanup_wq, &virqfd->shutdown);
-}
-
-static int virqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key)
-{
- struct virqfd *virqfd = container_of(wait, struct virqfd, wait);
- unsigned long flags = (unsigned long)key;
-
- if (flags & POLLIN) {
- /* An event has been signaled, call function */
- if ((!virqfd->handler ||
- virqfd->handler(virqfd->opaque, virqfd->data)) &&
- virqfd->thread)
- schedule_work(&virqfd->inject);
- }
-
- if (flags & POLLHUP) {
- unsigned long flags;
- spin_lock_irqsave(&virqfd_lock, flags);
-
- /*
- * The eventfd is closing, if the virqfd has not yet been
- * queued for release, as determined by testing whether the
- * virqfd pointer to it is still valid, queue it now. As
- * with kvm irqfds, we know we won't race against the virqfd
- * going away because we hold the lock to get here.
- */
- if (*(virqfd->pvirqfd) == virqfd) {
- *(virqfd->pvirqfd) = NULL;
- virqfd_deactivate(virqfd);
- }
-
- spin_unlock_irqrestore(&virqfd_lock, flags);
- }
-
- return 0;
-}
-
-static void virqfd_ptable_queue_proc(struct file *file,
- wait_queue_head_t *wqh, poll_table *pt)
-{
- struct virqfd *virqfd = container_of(pt, struct virqfd, pt);
- add_wait_queue(wqh, &virqfd->wait);
-}
-
-static void virqfd_shutdown(struct work_struct *work)
-{
- struct virqfd *virqfd = container_of(work, struct virqfd, shutdown);
- u64 cnt;
-
- eventfd_ctx_remove_wait_queue(virqfd->eventfd, &virqfd->wait, &cnt);
- flush_work(&virqfd->inject);
- eventfd_ctx_put(virqfd->eventfd);
-
- kfree(virqfd);
-}
-
-static void virqfd_inject(struct work_struct *work)
-{
- struct virqfd *virqfd = container_of(work, struct virqfd, inject);
- if (virqfd->thread)
- virqfd->thread(virqfd->opaque, virqfd->data);
-}
-
-int vfio_virqfd_enable(void *opaque,
- int (*handler)(void *, void *),
- void (*thread)(void *, void *),
- void *data, struct virqfd **pvirqfd, int fd)
-{
- struct fd irqfd;
- struct eventfd_ctx *ctx;
- struct virqfd *virqfd;
- int ret = 0;
- unsigned int events;
-
- virqfd = kzalloc(sizeof(*virqfd), GFP_KERNEL);
- if (!virqfd)
- return -ENOMEM;
-
- virqfd->pvirqfd = pvirqfd;
- virqfd->opaque = opaque;
- virqfd->handler = handler;
- virqfd->thread = thread;
- virqfd->data = data;
-
- INIT_WORK(&virqfd->shutdown, virqfd_shutdown);
- INIT_WORK(&virqfd->inject, virqfd_inject);
-
- irqfd = fdget(fd);
- if (!irqfd.file) {
- ret = -EBADF;
- goto err_fd;
- }
-
- ctx = eventfd_ctx_fileget(irqfd.file);
- if (IS_ERR(ctx)) {
- ret = PTR_ERR(ctx);
- goto err_ctx;
- }
-
- virqfd->eventfd = ctx;
-
- /*
- * virqfds can be released by closing the eventfd or directly
- * through ioctl. These are both done through a workqueue, so
- * we update the pointer to the virqfd under lock to avoid
- * pushing multiple jobs to release the same virqfd.
- */
- spin_lock_irq(&virqfd_lock);
-
- if (*pvirqfd) {
- spin_unlock_irq(&virqfd_lock);
- ret = -EBUSY;
- goto err_busy;
- }
- *pvirqfd = virqfd;
-
- spin_unlock_irq(&virqfd_lock);
-
- /*
- * Install our own custom wake-up handling so we are notified via
- * a callback whenever someone signals the underlying eventfd.
- */
- init_waitqueue_func_entry(&virqfd->wait, virqfd_wakeup);
- init_poll_funcptr(&virqfd->pt, virqfd_ptable_queue_proc);
-
- events = irqfd.file->f_op->poll(irqfd.file, &virqfd->pt);
-
- /*
- * Check if there was an event already pending on the eventfd
- * before we registered and trigger it as if we didn't miss it.
- */
- if (events & POLLIN) {
- if ((!handler || handler(opaque, data)) && thread)
- schedule_work(&virqfd->inject);
- }
-
- /*
- * Do not drop the file until the irqfd is fully initialized,
- * otherwise we might race against the POLLHUP.
- */
- fdput(irqfd);
-
- return 0;
-err_busy:
- eventfd_ctx_put(ctx);
-err_ctx:
- fdput(irqfd);
-err_fd:
- kfree(virqfd);
-
- return ret;
-}
-EXPORT_SYMBOL_GPL(vfio_virqfd_enable);
-
-void vfio_virqfd_disable(struct virqfd **pvirqfd)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&virqfd_lock, flags);
-
- if (*pvirqfd) {
- virqfd_deactivate(*pvirqfd);
- *pvirqfd = NULL;
- }
-
- spin_unlock_irqrestore(&virqfd_lock, flags);
-
- /*
- * Block until we know all outstanding shutdown jobs have completed.
- * Even if we don't queue the job, flush the wq to be sure it's
- * been released.
- */
- flush_workqueue(vfio_irqfd_cleanup_wq);
-}
-EXPORT_SYMBOL_GPL(vfio_virqfd_disable);
-
-/*
* INTx
*/
static void vfio_send_intx_eventfd(void *opaque, void *unused)
diff --git a/drivers/vfio/pci/vfio_pci_private.h b/drivers/vfio/pci/vfio_pci_private.h
index 0253965..ae0e1b4 100644
--- a/drivers/vfio/pci/vfio_pci_private.h
+++ b/drivers/vfio/pci/vfio_pci_private.h
@@ -87,9 +87,6 @@ extern ssize_t vfio_pci_vga_rw(struct vfio_pci_device *vdev, char __user *buf,
extern int vfio_pci_init_perm_bits(void);
extern void vfio_pci_uninit_perm_bits(void);

-extern int vfio_virqfd_init(void);
-extern void vfio_virqfd_exit(void);
-
extern int vfio_config_init(struct vfio_pci_device *vdev);
extern void vfio_config_free(struct vfio_pci_device *vdev);
#endif /* VFIO_PCI_PRIVATE_H */
diff --git a/drivers/vfio/virqfd.c b/drivers/vfio/virqfd.c
new file mode 100644
index 0000000..5967899
--- /dev/null
+++ b/drivers/vfio/virqfd.c
@@ -0,0 +1,213 @@
+/*
+ * VFIO generic eventfd code for IRQFD support.
+ * Derived from drivers/vfio/pci/vfio_pci_intrs.c
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All rights reserved.
+ * Author: Alex Williamson <alex.williamson-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/vfio.h>
+#include <linux/eventfd.h>
+#include <linux/file.h>
+#include <linux/slab.h>
+
+static struct workqueue_struct *vfio_irqfd_cleanup_wq;
+DEFINE_SPINLOCK(virqfd_lock);
+
+int __init vfio_virqfd_init(void)
+{
+ vfio_irqfd_cleanup_wq =
+ create_singlethread_workqueue("vfio-irqfd-cleanup");
+ if (!vfio_irqfd_cleanup_wq)
+ return -ENOMEM;
+
+ return 0;
+}
+
+void vfio_virqfd_exit(void)
+{
+ destroy_workqueue(vfio_irqfd_cleanup_wq);
+}
+
+static void virqfd_deactivate(struct virqfd *virqfd)
+{
+ queue_work(vfio_irqfd_cleanup_wq, &virqfd->shutdown);
+}
+
+static int virqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key)
+{
+ struct virqfd *virqfd = container_of(wait, struct virqfd, wait);
+ unsigned long flags = (unsigned long)key;
+
+ if (flags & POLLIN) {
+ /* An event has been signaled, call function */
+ if ((!virqfd->handler ||
+ virqfd->handler(virqfd->opaque, virqfd->data)) &&
+ virqfd->thread)
+ schedule_work(&virqfd->inject);
+ }
+
+ if (flags & POLLHUP) {
+ unsigned long flags;
+ spin_lock_irqsave(&virqfd_lock, flags);
+
+ /*
+ * The eventfd is closing, if the virqfd has not yet been
+ * queued for release, as determined by testing whether the
+ * virqfd pointer to it is still valid, queue it now. As
+ * with kvm irqfds, we know we won't race against the virqfd
+ * going away because we hold the lock to get here.
+ */
+ if (*(virqfd->pvirqfd) == virqfd) {
+ *(virqfd->pvirqfd) = NULL;
+ virqfd_deactivate(virqfd);
+ }
+
+ spin_unlock_irqrestore(&virqfd_lock, flags);
+ }
+
+ return 0;
+}
+
+static void virqfd_ptable_queue_proc(struct file *file,
+ wait_queue_head_t *wqh, poll_table *pt)
+{
+ struct virqfd *virqfd = container_of(pt, struct virqfd, pt);
+ add_wait_queue(wqh, &virqfd->wait);
+}
+
+static void virqfd_shutdown(struct work_struct *work)
+{
+ struct virqfd *virqfd = container_of(work, struct virqfd, shutdown);
+ u64 cnt;
+
+ eventfd_ctx_remove_wait_queue(virqfd->eventfd, &virqfd->wait, &cnt);
+ flush_work(&virqfd->inject);
+ eventfd_ctx_put(virqfd->eventfd);
+
+ kfree(virqfd);
+}
+
+static void virqfd_inject(struct work_struct *work)
+{
+ struct virqfd *virqfd = container_of(work, struct virqfd, inject);
+ if (virqfd->thread)
+ virqfd->thread(virqfd->opaque, virqfd->data);
+}
+
+int vfio_virqfd_enable(void *opaque,
+ int (*handler)(void *, void *),
+ void (*thread)(void *, void *),
+ void *data, struct virqfd **pvirqfd, int fd)
+{
+ struct fd irqfd;
+ struct eventfd_ctx *ctx;
+ struct virqfd *virqfd;
+ int ret = 0;
+ unsigned int events;
+
+ virqfd = kzalloc(sizeof(*virqfd), GFP_KERNEL);
+ if (!virqfd)
+ return -ENOMEM;
+
+ virqfd->pvirqfd = pvirqfd;
+ virqfd->opaque = opaque;
+ virqfd->handler = handler;
+ virqfd->thread = thread;
+ virqfd->data = data;
+
+ INIT_WORK(&virqfd->shutdown, virqfd_shutdown);
+ INIT_WORK(&virqfd->inject, virqfd_inject);
+
+ irqfd = fdget(fd);
+ if (!irqfd.file) {
+ ret = -EBADF;
+ goto err_fd;
+ }
+
+ ctx = eventfd_ctx_fileget(irqfd.file);
+ if (IS_ERR(ctx)) {
+ ret = PTR_ERR(ctx);
+ goto err_ctx;
+ }
+
+ virqfd->eventfd = ctx;
+
+ /*
+ * virqfds can be released by closing the eventfd or directly
+ * through ioctl. These are both done through a workqueue, so
+ * we update the pointer to the virqfd under lock to avoid
+ * pushing multiple jobs to release the same virqfd.
+ */
+ spin_lock_irq(&virqfd_lock);
+
+ if (*pvirqfd) {
+ spin_unlock_irq(&virqfd_lock);
+ ret = -EBUSY;
+ goto err_busy;
+ }
+ *pvirqfd = virqfd;
+
+ spin_unlock_irq(&virqfd_lock);
+
+ /*
+ * Install our own custom wake-up handling so we are notified via
+ * a callback whenever someone signals the underlying eventfd.
+ */
+ init_waitqueue_func_entry(&virqfd->wait, virqfd_wakeup);
+ init_poll_funcptr(&virqfd->pt, virqfd_ptable_queue_proc);
+
+ events = irqfd.file->f_op->poll(irqfd.file, &virqfd->pt);
+
+ /*
+ * Check if there was an event already pending on the eventfd
+ * before we registered and trigger it as if we didn't miss it.
+ */
+ if (events & POLLIN) {
+ if ((!handler || handler(opaque, data)) && thread)
+ schedule_work(&virqfd->inject);
+ }
+
+ /*
+ * Do not drop the file until the irqfd is fully initialized,
+ * otherwise we might race against the POLLHUP.
+ */
+ fdput(irqfd);
+
+ return 0;
+err_busy:
+ eventfd_ctx_put(ctx);
+err_ctx:
+ fdput(irqfd);
+err_fd:
+ kfree(virqfd);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(vfio_virqfd_enable);
+
+void vfio_virqfd_disable(struct virqfd **pvirqfd)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&virqfd_lock, flags);
+
+ if (*pvirqfd) {
+ virqfd_deactivate(*pvirqfd);
+ *pvirqfd = NULL;
+ }
+
+ spin_unlock_irqrestore(&virqfd_lock, flags);
+
+ /*
+ * Block until we know all outstanding shutdown jobs have completed.
+ * Even if we don't queue the job, flush the wq to be sure it's
+ * been released.
+ */
+ flush_workqueue(vfio_irqfd_cleanup_wq);
+}
+EXPORT_SYMBOL_GPL(vfio_virqfd_disable);
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 2d67b89..683b514 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -14,6 +14,8 @@

#include <linux/iommu.h>
#include <linux/mm.h>
+#include <linux/workqueue.h>
+#include <linux/poll.h>
#include <uapi/linux/vfio.h>

/**
@@ -123,4 +125,29 @@ static inline long vfio_spapr_iommu_eeh_ioctl(struct iommu_group *group,
return -ENOTTY;
}
#endif /* CONFIG_EEH */
+
+/*
+ * IRQfd - generic
+ */
+struct virqfd {
+ void *opaque;
+ struct eventfd_ctx *eventfd;
+ int (*handler)(void *, void *);
+ void (*thread)(void *, void *);
+ void *data;
+ struct work_struct inject;
+ wait_queue_t wait;
+ poll_table pt;
+ struct work_struct shutdown;
+ struct virqfd **pvirqfd;
+};
+
+extern int vfio_virqfd_init(void);
+extern void vfio_virqfd_exit(void);
+extern int vfio_virqfd_enable(void *opaque,
+ int (*handler)(void *, void *),
+ void (*thread)(void *, void *),
+ void *data, struct virqfd **pvirqfd, int fd);
+extern void vfio_virqfd_disable(struct virqfd **pvirqfd);
+
#endif /* VFIO_H */
--
2.3.1