Re: [Minios-devel] [UNIKRAFT PATCH v3 09/17] plat/xen/drivers/blk: Enable/disable interrupts for queues

[Costin Lupu <costin.lupu@xxxxxxxxx>]

Reviewed-by: Costin Lupu <costin.lupu@xxxxxxxxx>

On 10/30/19 5:54 PM, Roxana Nicolescu wrote:
> This patch introduces support for the user to enable/disable interrupts
> on queues.
> 
> Signed-off-by: Roxana Nicolescu <nicolescu.roxana1996@xxxxxxxxx>
> ---
>  plat/xen/drivers/blk/blkfront.c | 66 +++++++++++++++++++++++++++++++++
>  plat/xen/drivers/blk/blkfront.h |  2 +
>  2 files changed, 68 insertions(+)
> 
> diff --git a/plat/xen/drivers/blk/blkfront.c b/plat/xen/drivers/blk/blkfront.c
> index 62b14f4c..63b1e778 100644
> --- a/plat/xen/drivers/blk/blkfront.c
> +++ b/plat/xen/drivers/blk/blkfront.c
> @@ -41,6 +41,8 @@
>  #include <uk/essentials.h>
>  #include <uk/arch/limits.h>
>  #include <uk/blkdev_driver.h>
> +#include <xen-x86/mm.h>
> +#include <xen-x86/mm_pv.h>
>  #include <xenbus/xenbus.h>
>  #include "blkfront.h"
>  #include "blkfront_xb.h"
> @@ -48,12 +50,34 @@
>  #define DRIVER_NAME          "xen-blkfront"
>  
>  
> +/* TODO Same interrupt macros we use in virtio-blk */
> +#define BLKFRONT_INTR_EN             (1 << 0)
> +#define BLKFRONT_INTR_EN_MASK        (1)
> +#define BLKFRONT_INTR_USR_EN         (1 << 1)
> +#define BLKFRONT_INTR_USR_EN_MASK    (2)
> +
>  /* Get blkfront_dev* which contains blkdev */
>  #define to_blkfront(blkdev) \
>       __containerof(blkdev, struct blkfront_dev, blkdev)
>  
>  static struct uk_alloc *drv_allocator;
>  
> +
> +/* Returns 1 if more responses available */
> +static int blkfront_xen_ring_intr_enable(struct uk_blkdev_queue *queue)
> +{
> +     int more;
> +
> +     /* Check if there are no more responses enabled */
> +     RING_FINAL_CHECK_FOR_RESPONSES(&queue->ring, more);
> +     if (!more) {
> +             /* No more responses, we can enable interrupts */
> +             queue->intr_enabled |= BLKFRONT_INTR_EN;
> +             unmask_evtchn(queue->evtchn);
> +     }
> +
> +     return (more > 0);
> +}
>  static int blkfront_ring_init(struct uk_blkdev_queue *queue)
>  {
>       struct blkif_sring *sring = NULL;
> @@ -98,6 +122,10 @@ static void blkfront_handler(evtchn_port_t port __unused,
>       UK_ASSERT(arg);
>       queue = (struct uk_blkdev_queue *)arg;
>  
> +     /* Disable the interrupt for the ring */
> +     queue->intr_enabled &= ~(BLKFRONT_INTR_EN);
> +     mask_evtchn(queue->evtchn);
> +
>       uk_blkdev_drv_queue_event(&queue->dev->blkdev, queue->queue_id);
>  }
>  
> @@ -122,6 +150,7 @@ static struct uk_blkdev_queue 
> *blkfront_queue_setup(struct uk_blkdev *blkdev,
>       queue->a = queue_conf->a;
>       queue->queue_id = queue_id;
>       queue->dev = dev;
> +     queue->intr_enabled = 0;
>       err = blkfront_ring_init(queue);
>       if (err) {
>               uk_pr_err("Failed to init ring: %d.\n", err);
> @@ -154,6 +183,41 @@ static int blkfront_queue_release(struct uk_blkdev 
> *blkdev,
>       unbind_evtchn(queue->evtchn);
>       blkfront_ring_fini(queue);
>  
> +
> +static int blkfront_queue_intr_enable(struct uk_blkdev *blkdev,
> +             struct uk_blkdev_queue *queue)
> +{
> +     int rc = 0;
> +
> +     UK_ASSERT(blkdev != NULL);
> +     UK_ASSERT(queue != NULL);
> +
> +     /* If the interrupt is enabled */
> +     if (queue->intr_enabled & BLKFRONT_INTR_EN)
> +             return 0;
> +
> +     /**
> +      * Enable the user configuration bit. This would cause the interrupt to
> +      * be enabled automatically if the interrupt could not be enabled now
> +      * due to data in the queue.
> +      */
> +     queue->intr_enabled = BLKFRONT_INTR_USR_EN;
> +     rc = blkfront_xen_ring_intr_enable(queue);
> +     if (!rc)
> +             queue->intr_enabled |= BLKFRONT_INTR_EN;
> +
> +     return rc;
> +}
> +
> +static int blkfront_queue_intr_disable(struct uk_blkdev *blkdev,
> +             struct uk_blkdev_queue *queue)
> +{
> +     UK_ASSERT(blkdev);
> +     UK_ASSERT(queue);
> +
> +     queue->intr_enabled &= ~(BLKFRONT_INTR_USR_EN | BLKFRONT_INTR_EN);
> +     mask_evtchn(queue->evtchn);
> +
>       return 0;
>  }
>  
> @@ -239,6 +303,8 @@ static const struct uk_blkdev_ops blkfront_ops = {
>       .queue_setup = blkfront_queue_setup,
>       .queue_release = blkfront_queue_release,
>       .dev_unconfigure = blkfront_unconfigure,
> +     .queue_intr_enable = blkfront_queue_intr_enable,
> +     .queue_intr_disable = blkfront_queue_intr_disable,
>  };
>  
>  /**
> diff --git a/plat/xen/drivers/blk/blkfront.h b/plat/xen/drivers/blk/blkfront.h
> index a8b0ca85..037c627a 100644
> --- a/plat/xen/drivers/blk/blkfront.h
> +++ b/plat/xen/drivers/blk/blkfront.h
> @@ -60,6 +60,8 @@ struct uk_blkdev_queue {
>       struct uk_alloc *a;
>       /* The libukblkdev queue identifier */
>       uint16_t queue_id;
> +     /* The flag to interrupt on the queue */
> +     int intr_enabled;
>       /* Reference to the Blkfront Device */
>       struct blkfront_dev *dev;
>  };
> 

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