Re: [PATCH v4 7/8] vfio/type1: Add domain at(de)taching group helpers

[Auger Eric <eric.auger@redhat.com>]

Hi Lu,

On 11/5/18 8:34 AM, Lu Baolu wrote:
> This adds helpers to attach or detach a domain to a
> group. This will replace iommu_attach_group() which
> only works for pci devices.
s/pci/non mdev?
> 
> If a domain is attaching to a group which includes the
> mediated devices, it should attach to the iommu device
> (a pci device which represents the mdev in iommu scope)
> instead. The added helper supports attaching domain to
> groups for both pci and mdev devices.
> 
> Cc: Ashok Raj <ashok.raj@intel.com>
> Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Cc: Kevin Tian <kevin.tian@intel.com>
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
> ---
>  drivers/vfio/vfio_iommu_type1.c | 114 ++++++++++++++++++++++++++++++--
>  1 file changed, 107 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index d9fd3188615d..178264b330e7 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -91,6 +91,7 @@ struct vfio_dma {
>  struct vfio_group {
>  	struct iommu_group	*iommu_group;
>  	struct list_head	next;
> +	bool			mdev_group;	/* An mdev group */
>  };
>  
>  /*
> @@ -1327,6 +1328,105 @@ static bool vfio_iommu_has_sw_msi(struct iommu_group *group, phys_addr_t *base)
>  	return ret;
>  }
>  
> +static struct device *vfio_mdev_get_iommu_device(struct device *dev)
> +{
> +	struct device *(*fn)(struct device *dev);
> +	struct device *iommu_parent;
> +
> +	fn = symbol_get(mdev_get_iommu_device);
> +	if (fn) {
> +		iommu_parent = fn(dev);
> +		symbol_put(mdev_get_iommu_device);
> +
> +		return iommu_parent;
> +	}
> +
> +	return NULL;
> +}
> +
> +static int vfio_mdev_set_domain(struct device *dev, struct iommu_domain *domain)
> +{
> +	int (*fn)(struct device *dev, void *domain);
> +	int ret;
> +
> +	fn = symbol_get(mdev_set_iommu_domain);
> +	if (fn) {
> +		ret = fn(dev, domain);
> +		symbol_put(mdev_set_iommu_domain);
> +
> +		return ret;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static int vfio_mdev_attach_domain(struct device *dev, void *data)
> +{
> +	struct iommu_domain *domain = data;
> +	struct device *iommu_device;
> +	int ret;
> +
> +	ret = vfio_mdev_set_domain(dev, domain);
> +	if (ret)
> +		return ret;
> +
> +	iommu_device = vfio_mdev_get_iommu_device(dev);
> +	if (iommu_device) {
> +		bool aux_mode = false;
> +
> +		iommu_get_dev_attr(iommu_device,
> +				   IOMMU_DEV_ATTR_AUXD_ENABLED, &aux_mode);
Don' you need to test the returned value before using aux_mode?
> +		if (aux_mode)
> +			return iommu_attach_device_aux(domain, iommu_device);
> +		else
> +			return iommu_attach_device(domain, iommu_device);
if for some reason the above ops fail, don't you want to call
vfio_mdev_set_domain(dev, NULL)

> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static int vfio_mdev_detach_domain(struct device *dev, void *data)
> +{
> +	struct iommu_domain *domain = data;
> +	struct device *iommu_device;
> +
> +	vfio_mdev_set_domain(dev, NULL);
> +	iommu_device = vfio_mdev_get_iommu_device(dev);
> +	if (iommu_device) {
> +		bool aux_mode = false;
> +
> +		iommu_get_dev_attr(iommu_device,
> +				   IOMMU_DEV_ATTR_AUXD_ENABLED, &aux_mode);
same here
> +		if (aux_mode)
> +			iommu_detach_device_aux(domain, iommu_device);
> +		else
> +			iommu_detach_device(domain, iommu_device);
> +	}
> +
> +	return 0;
> +}
> +
> +static int vfio_iommu_attach_group(struct vfio_domain *domain,
> +				   struct vfio_group *group)
> +{
> +	if (group->mdev_group)
> +		return iommu_group_for_each_dev(group->iommu_group,
> +						domain->domain,
> +						vfio_mdev_attach_domain);
> +	else
> +		return iommu_attach_group(domain->domain, group->iommu_group);
> +}
> +
> +static void vfio_iommu_detach_group(struct vfio_domain *domain,
> +				    struct vfio_group *group)
> +{
> +	if (group->mdev_group)
> +		iommu_group_for_each_dev(group->iommu_group, domain->domain,
> +					 vfio_mdev_detach_domain);
> +	else
> +		iommu_detach_group(domain->domain, group->iommu_group);
> +}
> +
>  static int vfio_iommu_type1_attach_group(void *iommu_data,
>  					 struct iommu_group *iommu_group)
>  {
> @@ -1402,7 +1502,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
>  			goto out_domain;
>  	}
>  
> -	ret = iommu_attach_group(domain->domain, iommu_group);
> +	ret = vfio_iommu_attach_group(domain, group);
>  	if (ret)
>  		goto out_domain;
>  
> @@ -1434,8 +1534,8 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
>  	list_for_each_entry(d, &iommu->domain_list, next) {
>  		if (d->domain->ops == domain->domain->ops &&
>  		    d->prot == domain->prot) {
> -			iommu_detach_group(domain->domain, iommu_group);
> -			if (!iommu_attach_group(d->domain, iommu_group)) {
> +			vfio_iommu_detach_group(domain, group);
> +			if (!vfio_iommu_attach_group(d, group)) {
>  				list_add(&group->next, &d->group_list);
>  				iommu_domain_free(domain->domain);
>  				kfree(domain);
> @@ -1443,7 +1543,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
>  				return 0;
>  			}
>  
> -			ret = iommu_attach_group(domain->domain, iommu_group);
> +			ret = vfio_iommu_attach_group(domain, group);
>  			if (ret)
>  				goto out_domain;
>  		}
> @@ -1469,7 +1569,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
>  	return 0;
>  
>  out_detach:
> -	iommu_detach_group(domain->domain, iommu_group);
> +	vfio_iommu_detach_group(domain, group);
>  out_domain:
>  	iommu_domain_free(domain->domain);
>  out_free:
> @@ -1560,7 +1660,7 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
>  		if (!group)
>  			continue;
>  
> -		iommu_detach_group(domain->domain, iommu_group);
> +		vfio_iommu_detach_group(domain, group);
>  		list_del(&group->next);
>  		kfree(group);
>  		/*
> @@ -1625,7 +1725,7 @@ static void vfio_release_domain(struct vfio_domain *domain, bool external)
>  	list_for_each_entry_safe(group, group_tmp,
>  				 &domain->group_list, next) {
>  		if (!external)
> -			iommu_detach_group(domain->domain, group->iommu_group);
> +			vfio_iommu_detach_group(domain, group);
>  		list_del(&group->next);
>  		kfree(group);
>  	}
> 
Thanks

Eric