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Message-ID: <5579C862.6090804@arm.com>
Date: Thu, 11 Jun 2015 18:41:54 +0100
From: Robin Murphy <robin.murphy@....com>
To: Joerg Roedel <joro@...tes.org>,
"iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>
CC: Will Deacon <Will.Deacon@....com>, Kukjin Kim <kgene@...nel.org>,
David Woodhouse <dwmw2@...radead.org>,
Heiko Stuebner <heiko@...ech.de>,
Hiroshi Doyu <hdoyu@...dia.com>,
Thierry Reding <thierry.reding@...il.com>,
Alex Williamson <alex.williamson@...hat.com>,
Laurent Pinchart <laurent.pinchart@...asonboard.com>,
Oded Gabbay <oded.gabbay@...il.com>,
"jroedel@...e.de" <jroedel@...e.de>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 08/22] iommu: Make sure a device is always attached to
a domain
On 28/05/15 17:41, Joerg Roedel wrote:
> From: Joerg Roedel <jroedel@...e.de>
>
> Make use of the default domain and re-attach a device to it
> when it is detached from another domain. Also enforce that a
> device has to be in the default domain before it can be
> attached to a different domain.
>
> Signed-off-by: Joerg Roedel <jroedel@...e.de>
> ---
> drivers/iommu/iommu.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 75 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index adeedd2..7bce522 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -52,6 +52,7 @@ struct iommu_group {
> char *name;
> int id;
> struct iommu_domain *default_domain;
> + struct iommu_domain *domain;
> };
>
> struct iommu_device {
> @@ -78,6 +79,12 @@ struct iommu_group_attribute iommu_group_attr_##_name = \
>
> static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus,
> unsigned type);
> +static int __iommu_attach_device(struct iommu_domain *domain,
> + struct device *dev);
> +static int __iommu_attach_group(struct iommu_domain *domain,
> + struct iommu_group *group);
> +static void __iommu_detach_group(struct iommu_domain *domain,
> + struct iommu_group *group);
>
> static ssize_t iommu_group_attr_show(struct kobject *kobj,
> struct attribute *__attr, char *buf)
> @@ -376,6 +383,8 @@ rename:
>
> mutex_lock(&group->mutex);
> list_add_tail(&device->list, &group->devices);
> + if (group->domain)
> + __iommu_attach_device(group->domain, dev);
> mutex_unlock(&group->mutex);
>
> /* Notify any listeners about change to group. */
> @@ -455,19 +464,30 @@ static int iommu_group_device_count(struct iommu_group *group)
> * The group->mutex is held across callbacks, which will block calls to
> * iommu_group_add/remove_device.
> */
> -int iommu_group_for_each_dev(struct iommu_group *group, void *data,
> - int (*fn)(struct device *, void *))
> +static int __iommu_group_for_each_dev(struct iommu_group *group, void *data,
> + int (*fn)(struct device *, void *))
> {
> struct iommu_device *device;
> int ret = 0;
>
> - mutex_lock(&group->mutex);
> list_for_each_entry(device, &group->devices, list) {
Maybe worth using list_for_each_entry_safe so we can reuse this for
things like group teardown?
> ret = fn(device->dev, data);
> if (ret)
> break;
> }
> + return ret;
> +}
> +
> +
> +int iommu_group_for_each_dev(struct iommu_group *group, void *data,
> + int (*fn)(struct device *, void *))
> +{
> + int ret;
> +
> + mutex_lock(&group->mutex);
> + ret = __iommu_group_for_each_dev(group, data, fn);
> mutex_unlock(&group->mutex);
> +
> return ret;
> }
> EXPORT_SYMBOL_GPL(iommu_group_for_each_dev);
> @@ -1013,7 +1033,7 @@ int iommu_attach_device(struct iommu_domain *domain, struct device *dev)
> if (iommu_group_device_count(group) != 1)
> goto out_unlock;
>
> - ret = __iommu_attach_device(domain, dev);
> + ret = __iommu_attach_group(domain, group);
>
> out_unlock:
> mutex_unlock(&group->mutex);
> @@ -1048,7 +1068,7 @@ void iommu_detach_device(struct iommu_domain *domain, struct device *dev)
> goto out_unlock;
> }
>
> - __iommu_detach_device(domain, dev);
> + __iommu_detach_group(domain, group);
>
> out_unlock:
> mutex_unlock(&group->mutex);
> @@ -1073,10 +1093,31 @@ static int iommu_group_do_attach_device(struct device *dev, void *data)
> return __iommu_attach_device(domain, dev);
> }
>
> +static int __iommu_attach_group(struct iommu_domain *domain,
> + struct iommu_group *group)
> +{
> + int ret;
> +
> + if (group->default_domain && group->domain != group->default_domain)
> + return -EBUSY;
> +
> + ret = __iommu_group_for_each_dev(group, domain,
> + iommu_group_do_attach_device);
> + if (ret == 0)
> + group->domain = domain;
> +
> + return ret;
> +}
> +
> int iommu_attach_group(struct iommu_domain *domain, struct iommu_group *group)
> {
> - return iommu_group_for_each_dev(group, domain,
> - iommu_group_do_attach_device);
> + int ret;
> +
> + mutex_lock(&group->mutex);
> + ret = __iommu_attach_group(domain, group);
> + mutex_unlock(&group->mutex);
> +
> + return ret;
> }
> EXPORT_SYMBOL_GPL(iommu_attach_group);
>
> @@ -1089,9 +1130,35 @@ static int iommu_group_do_detach_device(struct device *dev, void *data)
> return 0;
> }
>
> +static void __iommu_detach_group(struct iommu_domain *domain,
> + struct iommu_group *group)
> +{
> + int ret;
> +
> + if (!group->default_domain) {
> + __iommu_group_for_each_dev(group, domain,
> + iommu_group_do_detach_device);
> + group->domain = NULL;
> + return;
> + }
> +
> + if (group->domain == group->default_domain)
> + return;
> +
> + /* Detach by re-attaching to the default domain */
> + ret = __iommu_group_for_each_dev(group, group->default_domain,
> + iommu_group_do_attach_device);
> + if (ret != 0)
> + WARN_ON(1);
> + else
if (!(WARN_ON(ret)) ?
Robin.
> + group->domain = group->default_domain;
> +}
> +
> void iommu_detach_group(struct iommu_domain *domain, struct iommu_group *group)
> {
> - iommu_group_for_each_dev(group, domain, iommu_group_do_detach_device);
> + mutex_lock(&group->mutex);
> + __iommu_detach_group(domain, group);
> + mutex_unlock(&group->mutex);
> }
> EXPORT_SYMBOL_GPL(iommu_detach_group);
>
>
--
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