Messages in this thread Patch in this message | | | Date | Sun, 24 Jul 2022 15:23:19 +0800 | Subject | Re: [PATCH v10 04/12] iommu: Add attach/detach_dev_pasid iommu interface | From | Baolu Lu <> |
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On 2022/7/23 22:11, Jason Gunthorpe wrote: >> + >> + /* >> + * Otherwise, the device came from DT/ACPI, assume it is static and >> + * then singleton can know from the device count in the group. >> + */ >> + return true; >> +} > I would be happer if probe was changed to refuse to add a device to a > group if the group's pasid xarray is not empty, as a protective > measure.
Agreed. I will add below code.
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 047898666b9f..e43cb6776087 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -895,6 +895,14 @@ int iommu_group_add_device(struct iommu_group *group, struct device *dev) int ret, i = 0; struct group_device *device;
+ /* + * The iommu_attach_device_pasid() requires a singleton group. + * Refuse to add a device into it if this assumption has been + * made. + */ + if (!xa_empty(group->pasid_array)) + return -EBUSY; + device = kzalloc(sizeof(*device), GFP_KERNEL); if (!device) return -ENOMEM; > >> +int iommu_attach_device_pasid(struct iommu_domain *domain, struct device *dev, >> + ioasid_t pasid) >> +{ >> + struct iommu_group *group; >> + void *curr; >> + int ret; >> + >> + if (!domain->ops->set_dev_pasid) >> + return -EOPNOTSUPP; >> + >> + group = iommu_group_get(dev); >> + if (!group || !iommu_group_immutable_singleton(group, dev)) { >> + iommu_group_put(group); >> + return -EINVAL; > goto error below > >> + } >> + >> + mutex_lock(&group->mutex); > Just hold the group->mutex a few lines above and don't put locking in > iommu_group_immutable_singleton(), it is clearer
Above two comments agreed. iommu_attach_device_pasid() looks like below after update.
int iommu_attach_device_pasid(struct iommu_domain *domain, struct device *dev, ioasid_t pasid) { struct iommu_group *group; int ret = -EINVAL; void *curr; if (!domain->ops->set_dev_pasid) return -EOPNOTSUPP; group = iommu_group_get(dev); if (!group) return -ENODEV; mutex_lock(&group->mutex); if (!iommu_group_immutable_singleton(group, dev)) goto out_unlock; curr = xa_cmpxchg(&group->pasid_array, pasid, NULL, domain, GFP_KERNEL); if (curr) { ret = xa_err(curr) ? : -EBUSY; goto out_unlock; } ret = domain->ops->set_dev_pasid(domain, dev, pasid); if (ret) xa_erase(&group->pasid_array, pasid); out_unlock: mutex_unlock(&group->mutex); iommu_group_put(group); return ret; } Best regards, baolu
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