Add a function which allows the max optimised IOMMU DMA size to be set. When set successfully, return -EPROBE_DEFER to inform the caller that the device driver needs to be reprobed to take effect.
Signed-off-by: John Garry <[email protected]> --- drivers/iommu/iommu.c | 47 +++++++++++++++++++++++++++++++++++++++++++ include/linux/iommu.h | 7 +++++++ 2 files changed, 54 insertions(+) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index bdb9aa47dfca..263d78e26c48 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -3058,6 +3058,53 @@ u32 iommu_sva_get_pasid(struct iommu_sva *handle) } EXPORT_SYMBOL_GPL(iommu_sva_get_pasid); +int iommu_set_dev_dma_opt_size(struct device *dev, size_t size) +{ + struct iommu_group *group = iommu_group_get(dev); + struct group_device *grp_dev; + struct device *_dev; + int ret, group_count; + + if (!group) + return 0; + + mutex_lock(&group->mutex); + + /* + * If already set, then ignore. We may have been set via sysfs, so + * honour that. + */ + if (group->max_opt_dma_size) { + ret = 0; + goto out; + } + + group_count = iommu_group_device_count(group); + if (group_count != 1) { + dev_err_ratelimited(dev, "Cannot change DMA opt size: Group has more than one device group_count=%d\n", + group_count); + ret = -EINVAL; + goto out; + } + + /* Since group has only one device */ + grp_dev = list_first_entry(&group->devices, struct group_device, list); + _dev = grp_dev->dev; + + if (_dev != dev) { + dev_err_ratelimited(dev, "Cannot set DMA max opt size - device has changed\n"); + ret = -EBUSY; + goto out; + } + + group->max_opt_dma_size = size; + ret = -EPROBE_DEFER; +out: + mutex_unlock(&group->mutex); + iommu_group_put(group); + return ret; +} + /* * Changes the default domain of an iommu group that has *only* one device * diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 6e187746af0f..36871e8ae636 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -428,6 +428,7 @@ extern void iommu_get_resv_regions(struct device *dev, struct list_head *list); extern void iommu_put_resv_regions(struct device *dev, struct list_head *list); extern void generic_iommu_put_resv_regions(struct device *dev, struct list_head *list); +extern int iommu_set_dev_dma_opt_size(struct device *dev, size_t size); extern void iommu_set_default_passthrough(bool cmd_line); extern void iommu_set_default_translated(bool cmd_line); extern bool iommu_default_passthrough(void); @@ -740,6 +741,12 @@ static inline int iommu_get_group_resv_regions(struct iommu_group *group, return -ENODEV; } +static inline int iommu_set_dev_dma_opt_size(struct device *dev, + size_t size) +{ + return -ENODEV; +} + static inline void iommu_set_default_passthrough(bool cmd_line) { } -- 2.26.2 _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
