On 20-10-21, 09:53, Dave Jiang wrote:
> The helper is called at the completion of the interrupt handle refresh
> event. It issues drain descriptors to each of the wq with associated
> interrupt handle. The drain descriptor will have interrupt request set but
> without completion record. This will ensure all descriptors with incorrect
> interrupt completion handle get drained and a completion interrupt is
> triggered for the guest driver to process them.
>
> Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
> Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
> ---
> drivers/dma/idxd/irq.c | 41 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 41 insertions(+)
>
> diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
> index 573a2f6d0f7f..8bca0ed2d23c 100644
> --- a/drivers/dma/idxd/irq.c
> +++ b/drivers/dma/idxd/irq.c
> @@ -55,6 +55,47 @@ static void idxd_device_reinit(struct work_struct *work)
> idxd_device_clear_state(idxd);
> }
>
> +/*
> + * The function sends a drain descriptor for the interrupt handle. The drain ensures
> + * all descriptors with this interrupt handle is flushed and the interrupt
> + * will allow the cleanup of the outstanding descriptors.
> + */
> +static void idxd_int_handle_revoke_drain(struct idxd_irq_entry *ie)
> +{
> + struct idxd_wq *wq = ie->wq;
> + struct idxd_device *idxd = ie->idxd;
> + struct device *dev = &idxd->pdev->dev;
> + struct dsa_hw_desc desc;
> + void __iomem *portal;
> + int rc;
> +
> + memset(&desc, 0, sizeof(desc));
declare and init it and avoid the memset:
struct dsa_hw_desc desc = {};
> +
> + /* Issue a simple drain operation with interrupt but no completion record */
> + desc.flags = IDXD_OP_FLAG_RCI;
> + desc.opcode = DSA_OPCODE_DRAIN;
> + desc.priv = 1;
> +
> + if (ie->pasid != INVALID_IOASID)
> + desc.pasid = ie->pasid;
> + desc.int_handle = ie->int_handle;
> + portal = idxd_wq_portal_addr(wq);
> +
> + /*
> + * The wmb() makes sure that the descriptor is all there before we
> + * issue.
> + */
> + wmb();
> + if (wq_dedicated(wq)) {
> + iosubmit_cmds512(portal, &desc, 1);
> + } else {
> + rc = enqcmds(portal, &desc);
> + /* This should not fail unless hardware failed. */
> + if (rc < 0)
> + dev_warn(dev, "Failed to submit drain desc on wq %d\n", wq->id);
> + }
> +}
> +
> static int process_misc_interrupts(struct idxd_device *idxd, u32 cause)
> {
> struct device *dev = &idxd->pdev->dev;
>
--
~Vinod
