[v2,8/8] iommu: Clean up open-coded ownership checks
Commit Message
Some drivers already implement their own defence against the possibility
of being given someone else's device. Since this is now taken care of by
the core code (and via a slightly different path from the original
fwspec-based idea), let's clean them up.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
v2: No change, but I'll note here that it's really about the fwspec->ops
checks; the !fwspec clauses are just going along for the ride where
that's clearly impossible as well. I plan to sweep for other
redundant checks in future when looking at the relevant flows.
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 3 ---
drivers/iommu/arm/arm-smmu/arm-smmu.c | 9 +--------
drivers/iommu/arm/arm-smmu/qcom_iommu.c | 14 ++------------
drivers/iommu/mtk_iommu.c | 7 +------
drivers/iommu/mtk_iommu_v1.c | 3 ---
drivers/iommu/sprd-iommu.c | 8 +-------
drivers/iommu/virtio-iommu.c | 3 ---
7 files changed, 5 insertions(+), 42 deletions(-)
Comments
On Thu, Jan 26, 2023 at 06:26:23PM +0000, Robin Murphy wrote:
> Some drivers already implement their own defence against the possibility
> of being given someone else's device. Since this is now taken care of by
> the core code (and via a slightly different path from the original
> fwspec-based idea), let's clean them up.
>
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> ---
>
> v2: No change, but I'll note here that it's really about the fwspec->ops
> checks; the !fwspec clauses are just going along for the ride where
> that's clearly impossible as well. I plan to sweep for other
> redundant checks in future when looking at the relevant flows.
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Jason
@@ -2642,9 +2642,6 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev)
struct arm_smmu_master *master;
struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
- if (!fwspec || fwspec->ops != &arm_smmu_ops)
- return ERR_PTR(-ENODEV);
-
if (WARN_ON_ONCE(dev_iommu_priv_get(dev)))
return ERR_PTR(-EBUSY);
@@ -1118,11 +1118,6 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
struct arm_smmu_device *smmu;
int ret;
- if (!fwspec || fwspec->ops != &arm_smmu_ops) {
- dev_err(dev, "cannot attach to SMMU, is it on the same bus?\n");
- return -ENXIO;
- }
-
/*
* FIXME: The arch/arm DMA API code tries to attach devices to its own
* domains between of_xlate() and probe_device() - we have no way to cope
@@ -1352,10 +1347,8 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev)
fwspec = dev_iommu_fwspec_get(dev);
if (ret)
goto out_free;
- } else if (fwspec && fwspec->ops == &arm_smmu_ops) {
- smmu = arm_smmu_get_by_fwnode(fwspec->iommu_fwnode);
} else {
- return ERR_PTR(-ENODEV);
+ smmu = arm_smmu_get_by_fwnode(fwspec->iommu_fwnode);
}
ret = -EINVAL;
@@ -79,16 +79,6 @@ static struct qcom_iommu_domain *to_qcom_iommu_domain(struct iommu_domain *dom)
static const struct iommu_ops qcom_iommu_ops;
-static struct qcom_iommu_dev * to_iommu(struct device *dev)
-{
- struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
-
- if (!fwspec || fwspec->ops != &qcom_iommu_ops)
- return NULL;
-
- return dev_iommu_priv_get(dev);
-}
-
static struct qcom_iommu_ctx * to_ctx(struct qcom_iommu_domain *d, unsigned asid)
{
struct qcom_iommu_dev *qcom_iommu = d->iommu;
@@ -361,7 +351,7 @@ static void qcom_iommu_domain_free(struct iommu_domain *domain)
static int qcom_iommu_attach_dev(struct iommu_domain *domain, struct device *dev)
{
- struct qcom_iommu_dev *qcom_iommu = to_iommu(dev);
+ struct qcom_iommu_dev *qcom_iommu = dev_iommu_priv_get(dev);
struct qcom_iommu_domain *qcom_domain = to_qcom_iommu_domain(domain);
int ret;
@@ -486,7 +476,7 @@ static bool qcom_iommu_capable(struct device *dev, enum iommu_cap cap)
static struct iommu_device *qcom_iommu_probe_device(struct device *dev)
{
- struct qcom_iommu_dev *qcom_iommu = to_iommu(dev);
+ struct qcom_iommu_dev *qcom_iommu = dev_iommu_priv_get(dev);
struct device_link *link;
if (!qcom_iommu)
@@ -776,16 +776,11 @@ static phys_addr_t mtk_iommu_iova_to_phys(struct iommu_domain *domain,
static struct iommu_device *mtk_iommu_probe_device(struct device *dev)
{
struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
- struct mtk_iommu_data *data;
+ struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
struct device_link *link;
struct device *larbdev;
unsigned int larbid, larbidx, i;
- if (!fwspec || fwspec->ops != &mtk_iommu_ops)
- return ERR_PTR(-ENODEV); /* Not a iommu client device */
-
- data = dev_iommu_priv_get(dev);
-
if (!MTK_IOMMU_IS_TYPE(data->plat_data, MTK_IOMMU_TYPE_MM))
return &data->iommu;
@@ -478,9 +478,6 @@ static struct iommu_device *mtk_iommu_v1_probe_device(struct device *dev)
idx++;
}
- if (!fwspec || fwspec->ops != &mtk_iommu_v1_ops)
- return ERR_PTR(-ENODEV); /* Not a iommu client device */
-
data = dev_iommu_priv_get(dev);
/* Link the consumer device with the smi-larb device(supplier) */
@@ -358,13 +358,7 @@ static phys_addr_t sprd_iommu_iova_to_phys(struct iommu_domain *domain,
static struct iommu_device *sprd_iommu_probe_device(struct device *dev)
{
- struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
- struct sprd_iommu_device *sdev;
-
- if (!fwspec || fwspec->ops != &sprd_iommu_ops)
- return ERR_PTR(-ENODEV);
-
- sdev = dev_iommu_priv_get(dev);
+ struct sprd_iommu_device *sdev = dev_iommu_priv_get(dev);
return &sdev->iommu;
}
@@ -945,9 +945,6 @@ static struct iommu_device *viommu_probe_device(struct device *dev)
struct viommu_dev *viommu = NULL;
struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
- if (!fwspec || fwspec->ops != &viommu_ops)
- return ERR_PTR(-ENODEV);
-
viommu = viommu_get_by_fwnode(fwspec->iommu_fwnode);
if (!viommu)
return ERR_PTR(-ENODEV);