Re: [PATCH] xen/arm : smmuv3: Fix to handle multiple StreamIds per device.

[Bertrand Marquis <Bertrand.Marquis@xxxxxxx>]

Hi Rahul,


> On 17 Feb 2021, at 10:05, Rahul Singh <Rahul.Singh@xxxxxxx> wrote:
> 
> SMMUv3 driver does not handle multiple StreamId if the master device
> supports more than one StreamID.
> 
> This bug was introduced when the driver was ported from Linux to XEN.
> dt_device_set_protected(..) should be called from add_device(..) not
> from the dt_xlate(..).
> 
> Move dt_device_set_protected(..) from dt_xlate(..) to add_device().
> 
> Signed-off-by: Rahul Singh <rahul.singh@xxxxxxx>
Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>

Thanks a lot, this is fixing issues with multiple stream ids for one device :-)

Cheers
Bertrand

> ---
> This patch is a candidate for 4.15 as without this patch it is not possible to
> assign multiple StreamIds to the same device when device is protected behind
> SMMUv3.
> ---
> xen/drivers/passthrough/arm/smmu-v3.c | 29 ++++++++++-----------------
> 1 file changed, 11 insertions(+), 18 deletions(-)
> 
> diff --git a/xen/drivers/passthrough/arm/smmu-v3.c 
> b/xen/drivers/passthrough/arm/smmu-v3.c
> index 914cdc1cf4..53d150cdb6 100644
> --- a/xen/drivers/passthrough/arm/smmu-v3.c
> +++ b/xen/drivers/passthrough/arm/smmu-v3.c
> @@ -2207,24 +2207,6 @@ static int arm_smmu_add_device(u8 devfn, struct device 
> *dev)
>        */
>       arm_smmu_enable_pasid(master);
> 
> -     return 0;
> -
> -err_free_master:
> -     xfree(master);
> -     dev_iommu_priv_set(dev, NULL);
> -     return ret;
> -}
> -
> -static int arm_smmu_dt_xlate(struct device *dev,
> -                             const struct dt_phandle_args *args)
> -{
> -     int ret;
> -     struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> -
> -     ret = iommu_fwspec_add_ids(dev, args->args, 1);
> -     if (ret)
> -             return ret;
> -
>       if (dt_device_is_protected(dev_to_dt(dev))) {
>               dev_err(dev, "Already added to SMMUv3\n");
>               return -EEXIST;
> @@ -2237,6 +2219,17 @@ static int arm_smmu_dt_xlate(struct device *dev,
>                       dev_name(fwspec->iommu_dev), fwspec->num_ids);
> 
>       return 0;
> +
> +err_free_master:
> +     xfree(master);
> +     dev_iommu_priv_set(dev, NULL);
> +     return ret;
> +}
> +
> +static int arm_smmu_dt_xlate(struct device *dev,
> +                             const struct dt_phandle_args *args)
> +{
> +     return iommu_fwspec_add_ids(dev, args->args, 1);
> }
> 
> /* Probing and initialisation functions */
> -- 
> 2.17.1
>