diff options
| author | CQ Tang <cq.tang@intel.com> | 2017-05-10 21:39:03 +0300 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2017-05-17 15:57:56 +0300 |
| commit | 15060aba717115dc9f204c02213a7c6bf341163e (patch) | |
| tree | 7ecaa7018f3cf6259a8b0344f63d727dbfccbab2 | |
| parent | 2ea659a9ef488125eb46da6eb571de5eae5c43f6 (diff) | |
| download | linux-15060aba717115dc9f204c02213a7c6bf341163e.tar.xz | |
iommu/vt-d: Helper function to query if a pasid has any active users
A driver would need to know if there are any active references to a
a PASID before cleaning up its resources. This function helps check
if there are any active users of a PASID before it can perform any
recovery on that device.
To: Joerg Roedel <joro@8bytes.org>
To: linux-kernel@vger.kernel.org
To: David Woodhouse <dwmw2@infradead.org>
Cc: Jean-Phillipe Brucker <jean-philippe.brucker@arm.com>
Cc: iommu@lists.linux-foundation.org
Signed-off-by: CQ Tang <cq.tang@intel.com>
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
| -rw-r--r-- | drivers/iommu/intel-svm.c | 30 | ||||
| -rw-r--r-- | include/linux/intel-svm.h | 20 |
2 files changed, 50 insertions, 0 deletions
diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c index 23c427602c55..f167c0d84ebf 100644 --- a/drivers/iommu/intel-svm.c +++ b/drivers/iommu/intel-svm.c @@ -489,6 +489,36 @@ int intel_svm_unbind_mm(struct device *dev, int pasid) } EXPORT_SYMBOL_GPL(intel_svm_unbind_mm); +int intel_svm_is_pasid_valid(struct device *dev, int pasid) +{ + struct intel_iommu *iommu; + struct intel_svm *svm; + int ret = -EINVAL; + + mutex_lock(&pasid_mutex); + iommu = intel_svm_device_to_iommu(dev); + if (!iommu || !iommu->pasid_table) + goto out; + + svm = idr_find(&iommu->pasid_idr, pasid); + if (!svm) + goto out; + + /* init_mm is used in this case */ + if (!svm->mm) + ret = 1; + else if (atomic_read(&svm->mm->mm_users) > 0) + ret = 1; + else + ret = 0; + + out: + mutex_unlock(&pasid_mutex); + + return ret; +} +EXPORT_SYMBOL_GPL(intel_svm_is_pasid_valid); + /* Page request queue descriptor */ struct page_req_dsc { u64 srr:1; diff --git a/include/linux/intel-svm.h b/include/linux/intel-svm.h index 3c25794042f9..99bc5b3ae26e 100644 --- a/include/linux/intel-svm.h +++ b/include/linux/intel-svm.h @@ -102,6 +102,21 @@ extern int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, */ extern int intel_svm_unbind_mm(struct device *dev, int pasid); +/** + * intel_svm_is_pasid_valid() - check if pasid is valid + * @dev: Device for which PASID was allocated + * @pasid: PASID value to be checked + * + * This function checks if the specified pasid is still valid. A + * valid pasid means the backing mm is still having a valid user. + * For kernel callers init_mm is always valid. for other mm, if mm->mm_users + * is non-zero, it is valid. + * + * returns -EINVAL if invalid pasid, 0 if pasid ref count is invalid + * 1 if pasid is valid. + */ +extern int intel_svm_is_pasid_valid(struct device *dev, int pasid); + #else /* CONFIG_INTEL_IOMMU_SVM */ static inline int intel_svm_bind_mm(struct device *dev, int *pasid, @@ -114,6 +129,11 @@ static inline int intel_svm_unbind_mm(struct device *dev, int pasid) { BUG(); } + +static int intel_svm_is_pasid_valid(struct device *dev, int pasid) +{ + return -EINVAL; +} #endif /* CONFIG_INTEL_IOMMU_SVM */ #define intel_svm_available(dev) (!intel_svm_bind_mm((dev), NULL, 0, NULL)) |