Re: [PATCH kernel v9 09/32] vfio: powerpc/spapr: Rework groups attaching

David Gibson
2015-04-29T03:27:45Z

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On Sat, Apr 25, 2015 at 10:14:33PM +1000, Alexey Kardashevskiy wrote:
> This is to make extended ownership and multiple groups support patches
> simpler for review.
>
> This should cause no behavioural change.

Um.. this doesn't appear to be true. Previously removing a group from
an enabled container would fail with EBUSY, now it forces a disable.

>
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> [aw: for the vfio related changes]
> Acked-by: Alex Williamson <alex.williamson@redhat.com>
> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
> ---
> drivers/vfio/vfio_iommu_spapr_tce.c | 40 ++++++++++++++++++++++---------------
> 1 file changed, 24 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
> index 115d5e6..0fbe03e 100644
> --- a/drivers/vfio/vfio_iommu_spapr_tce.c
> +++ b/drivers/vfio/vfio_iommu_spapr_tce.c
> @@ -460,16 +460,21 @@ static int tce_iommu_attach_group(void *iommu_data,
> iommu_group_id(container->tbl->it_group),
> iommu_group_id(iommu_group));
> ret = -EBUSY;
> - } else if (container->enabled) {
> + goto unlock_exit;
> + }
> +
> + if (container->enabled) {
> pr_err("tce_vfio: attaching group #%u to enabled container\n",
> iommu_group_id(iommu_group));
> ret = -EBUSY;
> - } else {
> - ret = iommu_take_ownership(tbl);
> - if (!ret)
> - container->tbl = tbl;
> + goto unlock_exit;
> }
>
> + ret = iommu_take_ownership(tbl);
> + if (!ret)
> + container->tbl = tbl;
> +
> +unlock_exit:
> mutex_unlock(&container->lock);
>
> return ret;
> @@ -487,19 +492,22 @@ static void tce_iommu_detach_group(void *iommu_data,
> pr_warn("tce_vfio: detaching group #%u, expected group is #%u\n",
> iommu_group_id(iommu_group),
> iommu_group_id(tbl->it_group));
> - } else {
> - if (container->enabled) {
> - pr_warn("tce_vfio: detaching group #%u from enabled container, forcing disable\n",
> - iommu_group_id(tbl->it_group));
> - tce_iommu_disable(container);
> - }
> + goto unlock_exit;
> + }
>
> - /* pr_debug("tce_vfio: detaching group #%u from iommu %p\n",
> - iommu_group_id(iommu_group), iommu_group); */
> - container->tbl = NULL;
> - tce_iommu_clear(container, tbl, tbl->it_offset, tbl->it_size);
> - iommu_release_ownership(tbl);
> + if (container->enabled) {
> + pr_warn("tce_vfio: detaching group #%u from enabled container, forcing disable\n",
> + iommu_group_id(tbl->it_group));
> + tce_iommu_disable(container);
> }
> +
> + /* pr_debug("tce_vfio: detaching group #%u from iommu %p\n",
> + iommu_group_id(iommu_group), iommu_group); */
> + container->tbl = NULL;
> + tce_iommu_clear(container, tbl, tbl->it_offset, tbl->it_size);
> + iommu_release_ownership(tbl);
> +
> +unlock_exit:
> mutex_unlock(&container->lock);
> }
>

--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson

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