From 15060aba717115dc9f204c02213a7c6bf341163e Mon Sep 17 00:00:00 2001 From: CQ Tang Date: Wed, 10 May 2017 11:39:03 -0700 Subject: 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 To: linux-kernel@vger.kernel.org To: David Woodhouse Cc: Jean-Phillipe Brucker Cc: iommu@lists.linux-foundation.org Signed-off-by: CQ Tang Signed-off-by: Ashok Raj Signed-off-by: Joerg Roedel --- drivers/iommu/intel-svm.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) (limited to 'drivers/iommu/intel-svm.c') 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; -- cgit v1.2.3