1. Patchew
  2. Xen
  3. [PATCH v5 0/9] SMMU handling for PCIe Passthrough on ARM
  4. View patch

[PATCH v5 2/9] iommu/arm: Add iommu_dt_xlate()

Stewart Hildebrand posted 9 patches 2 years, 4 months ago
There is a newer version of this series
[PATCH v5 2/9] iommu/arm: Add iommu_dt_xlate()
Posted by Stewart Hildebrand 2 years, 4 months ago 
From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

Move code for processing DT IOMMU specifier to a separate helper.
This helper will be re-used for adding PCI devices by the subsequent
patches as we will need exact the same actions for processing
DT PCI-IOMMU specifier.

While at it introduce NO_IOMMU to avoid magic "1".

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Signed-off-by: Stewart Hildebrand <stewart.hildebrand@amd.com>
---
v4->v5:
* rebase on top of "dynamic node programming using overlay dtbo" series
* move #define NO_IOMMU 1 to header
* s/these/this/ inside comment

v3->v4:
* make dt_phandle_args *iommu_spec const
* move !ops->add_device check to helper

v2->v3:
* no change

v1->v2:
* no change

downstream->v1:
* trivial rebase
* s/dt_iommu_xlate/iommu_dt_xlate/

(cherry picked from commit c26bab0415ca303df86aba1d06ef8edc713734d3 from
 the downstream branch poc/pci-passthrough from
 https://gitlab.com/xen-project/people/bmarquis/xen-arm-poc.git)
---
 xen/drivers/passthrough/device_tree.c | 48 +++++++++++++++++----------
 xen/include/xen/iommu.h               |  2 ++
 2 files changed, 32 insertions(+), 18 deletions(-)

diff --git a/xen/drivers/passthrough/device_tree.c b/xen/drivers/passthrough/device_tree.c
index 075fb25a3706..159ace9856c9 100644
--- a/xen/drivers/passthrough/device_tree.c
+++ b/xen/drivers/passthrough/device_tree.c
@@ -137,6 +137,30 @@ int iommu_release_dt_devices(struct domain *d)
     return 0;
 }
 
+static int iommu_dt_xlate(struct device *dev,
+                          const struct dt_phandle_args *iommu_spec)
+{
+    const struct iommu_ops *ops = iommu_get_ops();
+    int rc;
+
+    if ( !ops->dt_xlate )
+        return -EINVAL;
+
+    if ( !dt_device_is_available(iommu_spec->np) )
+        return NO_IOMMU;
+
+    rc = iommu_fwspec_init(dev, &iommu_spec->np->dev);
+    if ( rc )
+        return rc;
+
+    /*
+     * Provide DT IOMMU specifier which describes the IOMMU master
+     * interfaces of that device (device IDs, etc) to the driver.
+     * The driver is responsible to decide how to interpret them.
+     */
+    return ops->dt_xlate(dev, iommu_spec);
+}
+
 int iommu_remove_dt_device(struct dt_device_node *np)
 {
     const struct iommu_ops *ops = iommu_get_ops();
@@ -146,7 +170,7 @@ int iommu_remove_dt_device(struct dt_device_node *np)
     ASSERT(rw_is_locked(&dt_host_lock));
 
     if ( !iommu_enabled )
-        return 1;
+        return NO_IOMMU;
 
     if ( !ops )
         return -EOPNOTSUPP;
@@ -187,12 +211,12 @@ int iommu_add_dt_device(struct dt_device_node *np)
     const struct iommu_ops *ops = iommu_get_ops();
     struct dt_phandle_args iommu_spec;
     struct device *dev = dt_to_dev(np);
-    int rc = 1, index = 0;
+    int rc = NO_IOMMU, index = 0;
 
     ASSERT(system_state < SYS_STATE_active || rw_is_locked(&dt_host_lock));
 
     if ( !iommu_enabled )
-        return 1;
+        return NO_IOMMU;
 
     if ( !ops )
         return -EINVAL;
@@ -215,27 +239,15 @@ int iommu_add_dt_device(struct dt_device_node *np)
     {
         /*
          * The driver which supports generic IOMMU DT bindings must have
-         * these callback implemented.
+         * this callback implemented.
          */
-        if ( !ops->add_device || !ops->dt_xlate )
+        if ( !ops->add_device )
         {
             rc = -EINVAL;
             goto fail;
         }
 
-        if ( !dt_device_is_available(iommu_spec.np) )
-            break;
-
-        rc = iommu_fwspec_init(dev, &iommu_spec.np->dev);
-        if ( rc )
-            break;
-
-        /*
-         * Provide DT IOMMU specifier which describes the IOMMU master
-         * interfaces of that device (device IDs, etc) to the driver.
-         * The driver is responsible to decide how to interpret them.
-         */
-        rc = ops->dt_xlate(dev, &iommu_spec);
+        rc = iommu_dt_xlate(dev, &iommu_spec);
         if ( rc )
             break;
 
diff --git a/xen/include/xen/iommu.h b/xen/include/xen/iommu.h
index 0e747b0bbc1c..8cd4b9a6bfb2 100644
--- a/xen/include/xen/iommu.h
+++ b/xen/include/xen/iommu.h
@@ -245,6 +245,8 @@ int iommu_do_dt_domctl(struct xen_domctl *domctl, struct domain *d,
  */
 int iommu_remove_dt_device(struct dt_device_node *np);
 
+#define NO_IOMMU    1
+
 #endif /* HAS_DEVICE_TREE */
 
 struct page_info;
-- 
2.42.0
Re: [PATCH v5 2/9] iommu/arm: Add iommu_dt_xlate()
Posted by Julien Grall 2 years, 3 months ago 
Hi Stewart,

On 04/10/2023 15:55, Stewart Hildebrand wrote:
> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
> 
> Move code for processing DT IOMMU specifier to a separate helper.
> This helper will be re-used for adding PCI devices by the subsequent
> patches as we will need exact the same actions for processing
> DT PCI-IOMMU specifier.
> 
> While at it introduce NO_IOMMU to avoid magic "1".
> 
> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
> Signed-off-by: Stewart Hildebrand <stewart.hildebrand@amd.com>
> ---
> v4->v5:
> * rebase on top of "dynamic node programming using overlay dtbo" series
> * move #define NO_IOMMU 1 to header
> * s/these/this/ inside comment
> 
> v3->v4:
> * make dt_phandle_args *iommu_spec const
> * move !ops->add_device check to helper
> 
> v2->v3:
> * no change
> 
> v1->v2:
> * no change
> 
> downstream->v1:
> * trivial rebase
> * s/dt_iommu_xlate/iommu_dt_xlate/
> 
> (cherry picked from commit c26bab0415ca303df86aba1d06ef8edc713734d3 from
>   the downstream branch poc/pci-passthrough from
>   https://gitlab.com/xen-project/people/bmarquis/xen-arm-poc.git)
> ---
>   xen/drivers/passthrough/device_tree.c | 48 +++++++++++++++++----------
>   xen/include/xen/iommu.h               |  2 ++
>   2 files changed, 32 insertions(+), 18 deletions(-)
> 
> diff --git a/xen/drivers/passthrough/device_tree.c b/xen/drivers/passthrough/device_tree.c
> index 075fb25a3706..159ace9856c9 100644
> --- a/xen/drivers/passthrough/device_tree.c
> +++ b/xen/drivers/passthrough/device_tree.c
> @@ -137,6 +137,30 @@ int iommu_release_dt_devices(struct domain *d)
>       return 0;
>   }
>   
> +static int iommu_dt_xlate(struct device *dev,
> +                          const struct dt_phandle_args *iommu_spec)
> +{
> +    const struct iommu_ops *ops = iommu_get_ops();

NIT: Rather than calling iommu_get_ops(), how about passing the ops as a 
parameter of iommu_dt_xlate()?

Reviewed-by: Julien Grall <jgrall@amazon.com>

Cheers,

-- 
Julien Grall
Re: [PATCH v5 2/9] iommu/arm: Add iommu_dt_xlate()
Posted by Stewart Hildebrand 2 years, 3 months ago 
On 10/24/23 14:39, Julien Grall wrote:
> Hi Stewart,
> 
> On 04/10/2023 15:55, Stewart Hildebrand wrote:
>> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
>>
>> Move code for processing DT IOMMU specifier to a separate helper.
>> This helper will be re-used for adding PCI devices by the subsequent
>> patches as we will need exact the same actions for processing
>> DT PCI-IOMMU specifier.
>>
>> While at it introduce NO_IOMMU to avoid magic "1".
>>
>> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
>> Signed-off-by: Stewart Hildebrand <stewart.hildebrand@amd.com>
>> ---
>> v4->v5:
>> * rebase on top of "dynamic node programming using overlay dtbo" series
>> * move #define NO_IOMMU 1 to header
>> * s/these/this/ inside comment
>>
>> v3->v4:
>> * make dt_phandle_args *iommu_spec const
>> * move !ops->add_device check to helper
>>
>> v2->v3:
>> * no change
>>
>> v1->v2:
>> * no change
>>
>> downstream->v1:
>> * trivial rebase
>> * s/dt_iommu_xlate/iommu_dt_xlate/
>>
>> (cherry picked from commit c26bab0415ca303df86aba1d06ef8edc713734d3 from
>>   the downstream branch poc/pci-passthrough from
>>   https://gitlab.com/xen-project/people/bmarquis/xen-arm-poc.git)
>> ---
>>   xen/drivers/passthrough/device_tree.c | 48 +++++++++++++++++----------
>>   xen/include/xen/iommu.h               |  2 ++
>>   2 files changed, 32 insertions(+), 18 deletions(-)
>>
>> diff --git a/xen/drivers/passthrough/device_tree.c b/xen/drivers/passthrough/device_tree.c
>> index 075fb25a3706..159ace9856c9 100644
>> --- a/xen/drivers/passthrough/device_tree.c
>> +++ b/xen/drivers/passthrough/device_tree.c
>> @@ -137,6 +137,30 @@ int iommu_release_dt_devices(struct domain *d)
>>       return 0;
>>   }
>>
>> +static int iommu_dt_xlate(struct device *dev,
>> +                          const struct dt_phandle_args *iommu_spec)
>> +{
>> +    const struct iommu_ops *ops = iommu_get_ops();
> 
> NIT: Rather than calling iommu_get_ops(), how about passing the ops as a
> parameter of iommu_dt_xlate()?

Yes, will do.

> 
> Reviewed-by: Julien Grall <jgrall@amazon.com>

Thanks!

> 
> Cheers,
> 
> -- 
> Julien Grall

Patchew 2.1-devel-b67e4c2

© 2016 - 2026 Red Hat, Inc.