xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

iommu/vt-d: Implement SVM_FLAG_SUPERVISOR_MODE for kernel access

Browse Source 
This is only usable for the static 1:1 mapping of physical memory.

Any access to vmalloc or module regions will require some way of doing
an IOTLB flush. It's theoretically possible to hook into the
tlb_flush_kernel_range() function, but that seems like overkill — most
of the addresses accessed through a kernel PASID *will* be in the 1:1
mapping.

If we really need to allow access to more interesting kernel regions,
then the answer will probably be an explicit IOTLB flush call after use,
akin to the DMA API's unmap function.

In fact, it might be worth introducing that sooner rather than later, and
making it just BUG() if the address isn't in the static 1:1 mapping.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This commit is contained in:
David Woodhouse
2015-10-15 15:52:15 +01:00
parent 569e4f7782
commit 5cec753709
2 changed files with 45 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

43
drivers/iommu/intel-svm.c
View File

@@ -269,11 +269,10 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_
struct intel_iommu *iommu = intel_svm_device_to_iommu(dev);
struct intel_svm_dev *sdev;
struct intel_svm *svm = NULL;
struct mm_struct *mm = NULL;
int pasid_max;
int ret;
BUG_ON(pasid && !current->mm);
if (WARN_ON(!iommu))
return -EINVAL;
@@ -284,12 +283,20 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_
} else
pasid_max = 1 << 20;
if ((flags & SVM_FLAG_SUPERVISOR_MODE)) {
if (!ecap_srs(iommu->ecap))
return -EINVAL;
} else if (pasid) {
mm = get_task_mm(current);
BUG_ON(!mm);
}
mutex_lock(&pasid_mutex);
if (pasid && !(flags & SVM_FLAG_PRIVATE_PASID)) {
int i;
idr_for_each_entry(&iommu->pasid_idr, svm, i) {
if (svm->mm != current->mm ||
if (svm->mm != mm ||
(svm->flags & SVM_FLAG_PRIVATE_PASID))
continue;
@@ -355,17 +362,22 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_
}
svm->pasid = ret;
svm->notifier.ops = &intel_mmuops;
svm->mm = get_task_mm(current);
svm->mm = mm;
svm->flags = flags;
INIT_LIST_HEAD_RCU(&svm->devs);
ret = -ENOMEM;
if (!svm->mm || (ret = mmu_notifier_register(&svm->notifier, svm->mm))) {
idr_remove(&svm->iommu->pasid_idr, svm->pasid);
kfree(svm);
kfree(sdev);
goto out;
}
iommu->pasid_table[svm->pasid].val = (u64)__pa(svm->mm->pgd) | 1;
if (mm) {
ret = mmu_notifier_register(&svm->notifier, mm);
if (ret) {
idr_remove(&svm->iommu->pasid_idr, svm->pasid);
kfree(svm);
kfree(sdev);
goto out;
}
iommu->pasid_table[svm->pasid].val = (u64)__pa(mm->pgd) | 1;
mm = NULL;
} else
iommu->pasid_table[svm->pasid].val = (u64)__pa(init_mm.pgd) | 1 | (1ULL << 11);
wmb();
}
list_add_rcu(&sdev->list, &svm->devs);
@@ -375,6 +387,8 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_
ret = 0;
out:
mutex_unlock(&pasid_mutex);
if (mm)
mmput(mm);
return ret;
}
EXPORT_SYMBOL_GPL(intel_svm_bind_mm);
@@ -416,7 +430,8 @@ int intel_svm_unbind_mm(struct device *dev, int pasid)
mmu_notifier_unregister(&svm->notifier, svm->mm);
idr_remove(&svm->iommu->pasid_idr, svm->pasid);
mmput(svm->mm);
if (svm->mm)
mmput(svm->mm);
/* We mandate that no page faults may be outstanding
* for the PASID when intel_svm_unbind_mm() is called.
* If that is not obeyed, subtle errors will happen.
@@ -500,6 +515,10 @@ static irqreturn_t prq_event_thread(int irq, void *d)
}
result = QI_RESP_INVALID;
/* Since we're using init_mm.pgd directly, we should never take
* any faults on kernel addresses. */
if (!svm->mm)
goto bad_req;
down_read(&svm->mm->mmap_sem);
vma = find_extend_vma(svm->mm, address);
if (!vma || address < vma->vm_start)