From dda2b8c3c6ccc50deae65cc75f246577348e2ec5 Mon Sep 17 00:00:00 2001 From: Lu Baolu Date: Fri, 13 Dec 2024 09:17:52 +0800 Subject: [PATCH] iommu/vt-d: Avoid draining PRQ in sva mm release path When a PASID is used for SVA by a device, it's possible that the PASID entry is cleared before the device flushes all ongoing DMA requests and removes the SVA domain. This can occur when an exception happens and the process terminates before the device driver stops DMA and calls the iommu driver to unbind the PASID. There's no need to drain the PRQ in the mm release path. Instead, the PRQ will be drained in the SVA unbind path. Unfortunately, commit c43e1ccdebf2 ("iommu/vt-d: Drain PRQs when domain removed from RID") changed this behavior by unconditionally draining the PRQ in intel_pasid_tear_down_entry(). This can lead to a potential sleeping-in-atomic-context issue. Smatch static checker warning: drivers/iommu/intel/prq.c:95 intel_iommu_drain_pasid_prq() warn: sleeping in atomic context To avoid this issue, prevent draining the PRQ in the SVA mm release path and restore the previous behavior. Fixes: c43e1ccdebf2 ("iommu/vt-d: Drain PRQs when domain removed from RID") Reported-by: Dan Carpenter Closes: https://lore.kernel.org/linux-iommu/c5187676-2fa2-4e29-94e0-4a279dc88b49@stanley.mountain/ Signed-off-by: Lu Baolu Reviewed-by: Kevin Tian Link: https://lore.kernel.org/r/20241212021529.1104745-1-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel --- drivers/iommu/intel/pasid.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c index 0f2a926d3bd5..5b7d85f1e143 100644 --- a/drivers/iommu/intel/pasid.c +++ b/drivers/iommu/intel/pasid.c @@ -265,7 +265,8 @@ void intel_pasid_tear_down_entry(struct intel_iommu *iommu, struct device *dev, iommu->flush.flush_iotlb(iommu, did, 0, 0, DMA_TLB_DSI_FLUSH); devtlb_invalidation_with_pasid(iommu, dev, pasid); - intel_iommu_drain_pasid_prq(dev, pasid); + if (!fault_ignore) + intel_iommu_drain_pasid_prq(dev, pasid); } /* -- 2.50.1