Skip to content

Commit

Permalink
vfio: move eventfd support code for VFIO_PCI to a separate file
Browse files Browse the repository at this point in the history 
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@virtualopensystems.com>
Signed-off-by: Baptiste Reynal <b.reynal@virtualopensystems.com>
Reviewed-by: Eric Auger <eric.auger@linaro.org>
Tested-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
  • Loading branch information
Antonios Motakis authored and Alex Williamson committed Mar 16, 2015
1 parent 09bbcb8 commit 7e992d6
Show file tree
Hide file tree
Showing 5 changed files with 242 additions and 219 deletions.
3 changes: 2 additions & 1 deletion drivers/vfio/pci/Makefile
View file
Original file line number Diff line number Diff line change
@@ -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
215 changes: 0 additions & 215 deletions drivers/vfio/pci/vfio_pci_intrs.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -19,227 +19,12 @@
#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
*/
Expand Down
3 changes: 0 additions & 3 deletions drivers/vfio/pci/vfio_pci_private.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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 */
Loading

0 comments on commit 7e992d6

Please sign in to comment.