On Sun, 19 Feb 2017 22:47:07 +0800
Lan Tianyu <tianyu.lan@xxxxxxxxx> wrote:
> This patch is to receive IOMMU fault eventfd and IOMMU fault event flag
> from userspace. VFIO should register IOMMU fault event handler according
> fault event flag which designates what kind of fault events need to be
> reported. When VFIO get IOMMU fault event from IOMMU driver, it should
> notify userspace via received fd.
>
> Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx>
> ---
> drivers/vfio/vfio_iommu_type1.c | 45 +++++++++++++++++++++++++++++++++++++++++
> include/uapi/linux/vfio.h | 15 ++++++++++++++
> 2 files changed, 60 insertions(+)
>
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index b3cc33f..46674ea 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -38,6 +38,7 @@
> #include <linux/workqueue.h>
> #include <linux/mdev.h>
> #include <linux/notifier.h>
> +#include <linux/eventfd.h>
>
> #define DRIVER_VERSION "0.2"
> #define DRIVER_AUTHOR "Alex Williamson <alex.williamson@xxxxxxxxxx>"
> @@ -61,6 +62,8 @@ struct vfio_iommu {
> struct mutex lock;
> struct rb_root dma_list;
> struct blocking_notifier_head notifier;
> + struct eventfd_ctx *iommu_fault_fd;
> + struct mutex fault_lock;
> bool v2;
> bool nesting;
> };
> @@ -1452,6 +1455,7 @@ static void *vfio_iommu_type1_open(unsigned long arg)
> INIT_LIST_HEAD(&iommu->domain_list);
> iommu->dma_list = RB_ROOT;
> mutex_init(&iommu->lock);
> + mutex_init(&iommu->fault_lock);
> BLOCKING_INIT_NOTIFIER_HEAD(&iommu->notifier);
>
> return iommu;
> @@ -1582,6 +1586,47 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
>
> return copy_to_user((void __user *)arg, &unmap, minsz) ?
> -EFAULT : 0;
> + } else if (cmd == VFIO_IOMMU_SET_FAULT_EVENTFD) {
> + struct vfio_iommu_type1_set_fault_eventfd eventfd;
> + int fd;
> + int ret;
> +
> + minsz = offsetofend(struct vfio_iommu_type1_set_fault_eventfd,
> + fd);
> +
> + if (copy_from_user(&eventfd, (void __user *)arg, minsz))
> + return -EFAULT;
> +
> + if (eventfd.argsz < minsz)
> + return -EINVAL;
> +
> +
> + mutex_lock(&iommu->fault_lock);
> +
> + fd = eventfd.fd;
> + if (fd == -1) {
> + if (iommu->iommu_fault_fd)
> + eventfd_ctx_put(iommu->iommu_fault_fd);
> + iommu->iommu_fault_fd = NULL;
> + ret = 0;
> + } else if (fd >= 0) {
> + struct eventfd_ctx *ctx;
> +
> + ctx = eventfd_ctx_fdget(fd);
> + if (IS_ERR(ctx))
> + return PTR_ERR(ctx);
> +
> + if (ctx)
> + eventfd_ctx_put(ctx);
> +
> + iommu->iommu_fault_fd = ctx;
> + ret = 0;
> + } else
> + ret = -EINVAL;
> +
> + mutex_unlock(&iommu->fault_lock);
> +
> + return ret;
> }
>
> return -ENOTTY;
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index 519eff3..8616334 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -547,6 +547,21 @@ struct vfio_iommu_type1_dma_unmap {
> #define VFIO_IOMMU_ENABLE _IO(VFIO_TYPE, VFIO_BASE + 15)
> #define VFIO_IOMMU_DISABLE _IO(VFIO_TYPE, VFIO_BASE + 16)
>
> +/*
> + * VFIO_IOMMU_SET_FAULT_EVENT_FD _IO(VFIO_TYPE, VFIO_BASE + 17)
> + *
> + * Receive eventfd from userspace to notify fault event from IOMMU.
> + */
> +struct vfio_iommu_type1_set_fault_eventfd {
> + __u32 argsz;
> + __u32 flags;
> +/* What IOMMU Fault events should be reported. */
> +#define VFIO_IOMMU_UR_FAULT_WITHOUT_PASID (1 << 0)
Is this a filter? Would multiple filters be allowed using the same
eventfd or would each type require a separate eventfd? How would a
user be able to probe what flags/filters are available? Should this
simply use the IRQ_INFO and SET_IRQ ioctls from the device file
descriptor for consistency?
> + __s32 fd; /* Eventfd from user space */
> +};
> +
> +#define VFIO_IOMMU_SET_FAULT_EVENTFD _IO(VFIO_TYPE, VFIO_BASE + 17)
> +
> /* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU -------- */
>
> /*
