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[XEN,v5,10/17] xen/iommu: Introduce iommu_remove_dt_device()

Message ID 20230411191636.26926-11-vikram.garhwal@amd.com (mailing list archive)
State Superseded
Headers show
Series dynamic node programming using overlay dtbo | expand

Commit Message

Vikram Garhwal April 11, 2023, 7:16 p.m. UTC
Remove master device from the IOMMU. This will be helpful when removing the
overlay nodes using dynamic programming during run time.

Signed-off-by: Vikram Garhwal <vikram.garhwal@amd.com>
---
 xen/drivers/passthrough/device_tree.c | 38 +++++++++++++++++++++++++++
 xen/include/xen/iommu.h               |  2 ++
 2 files changed, 40 insertions(+)

Comments

Michal Orzel April 17, 2023, 10:49 a.m. UTC | #1
Hi Vikram,

On 11/04/2023 21:16, Vikram Garhwal wrote:
> 
> 
> Remove master device from the IOMMU. This will be helpful when removing the
> overlay nodes using dynamic programming during run time.
> 
> Signed-off-by: Vikram Garhwal <vikram.garhwal@amd.com>
> ---
>  xen/drivers/passthrough/device_tree.c | 38 +++++++++++++++++++++++++++
>  xen/include/xen/iommu.h               |  2 ++
>  2 files changed, 40 insertions(+)
> 
> diff --git a/xen/drivers/passthrough/device_tree.c b/xen/drivers/passthrough/device_tree.c
> index 457df333a0..a77a217f3d 100644
> --- a/xen/drivers/passthrough/device_tree.c
> +++ b/xen/drivers/passthrough/device_tree.c
> @@ -126,6 +126,44 @@ int iommu_release_dt_devices(struct domain *d)
>      return 0;
>  }
> 
> +int iommu_remove_dt_device(struct dt_device_node *np)
> +{
> +    const struct iommu_ops *ops = iommu_get_ops();
> +    struct device *dev = dt_to_dev(np);
> +    int rc;
> +
> +    if ( !ops )
> +        return -EOPNOTSUPP;
> +
> +    spin_lock(&dtdevs_lock);
> +
> +    if ( iommu_dt_device_is_assigned_locked(np) )
> +    {
> +        rc = -EBUSY;
> +        goto fail;
> +    }
> +
> +    /*
> +     * The driver which supports generic IOMMU DT bindings must have
> +     * these callback implemented.
s/these/this since you are checking for a single callback.

> +     */
> +    if ( !ops->remove_device )
> +    {
> +        rc = -EOPNOTSUPP;
> +        goto fail;
> +    }
> +
> +    /* Remove master device from the IOMMU if latter is present and available. */
80 chars length exceeded -> please fix.
Apart from that, similarly to comment inside iommu_add_dt_device(), I would also write
something that the driver is responsible for unsetting is_protected flag.

Apart from that:
Reviewed-by: Michal Orzel <michal.orzel@amd.com>

~Michal
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Patch

diff --git a/xen/drivers/passthrough/device_tree.c b/xen/drivers/passthrough/device_tree.c
index 457df333a0..a77a217f3d 100644
--- a/xen/drivers/passthrough/device_tree.c
+++ b/xen/drivers/passthrough/device_tree.c
@@ -126,6 +126,44 @@  int iommu_release_dt_devices(struct domain *d)
     return 0;
 }
 
+int iommu_remove_dt_device(struct dt_device_node *np)
+{
+    const struct iommu_ops *ops = iommu_get_ops();
+    struct device *dev = dt_to_dev(np);
+    int rc;
+
+    if ( !ops )
+        return -EOPNOTSUPP;
+
+    spin_lock(&dtdevs_lock);
+
+    if ( iommu_dt_device_is_assigned_locked(np) )
+    {
+        rc = -EBUSY;
+        goto fail;
+    }
+
+    /*
+     * The driver which supports generic IOMMU DT bindings must have
+     * these callback implemented.
+     */
+    if ( !ops->remove_device )
+    {
+        rc = -EOPNOTSUPP;
+        goto fail;
+    }
+
+    /* Remove master device from the IOMMU if latter is present and available. */
+    rc = ops->remove_device(0, dev);
+
+    if ( !rc )
+        iommu_fwspec_free(dev);
+
+fail:
+    spin_unlock(&dtdevs_lock);
+    return rc;
+}
+
 int iommu_add_dt_device(struct dt_device_node *np)
 {
     const struct iommu_ops *ops = iommu_get_ops();
diff --git a/xen/include/xen/iommu.h b/xen/include/xen/iommu.h
index 405db59971..079c06321e 100644
--- a/xen/include/xen/iommu.h
+++ b/xen/include/xen/iommu.h
@@ -218,6 +218,8 @@  int iommu_deassign_dt_device(struct domain *d, struct dt_device_node *dev);
 int iommu_dt_domain_init(struct domain *d);
 int iommu_release_dt_devices(struct domain *d);
 
+int iommu_remove_dt_device(struct dt_device_node *np);
+
 /*
  * Helper to add master device to the IOMMU using generic IOMMU DT bindings.
  *