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Groups > linux.kernel > #1721650

[PATCH] intel-iommu: Don't be too aggressive when clearing one context entry

From Filippo Sironi <sironi@amazon.de>
Newsgroups linux.kernel
Subject [PATCH] intel-iommu: Don't be too aggressive when clearing one context entry
Date 2017-08-28 16:20 +0200
Message-ID <ujt3s-6CP-9@gated-at.bofh.it> (permalink)
Organization linux.* mail to news gateway

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Previously, we were invalidating context cache and IOTLB globally when
clearing one context entry.  This is a tad too aggressive.
Invalidate the context cache and IOTLB for the interested device only.

Signed-off-by: Filippo Sironi <sironi@amazon.de>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: iommu@lists.linux-foundation.org
Cc: linux-kernel@vger.kernel.org
---
 drivers/iommu/intel-iommu.c | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 3e8636f1220e..4bf3e59b0929 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -2351,13 +2351,32 @@ static inline int domain_pfn_mapping(struct dmar_domain *domain, unsigned long i
 
 static void domain_context_clear_one(struct intel_iommu *iommu, u8 bus, u8 devfn)
 {
+	unsigned long flags;
+	struct context_entry *context;
+	u16 did_old;
+
 	if (!iommu)
 		return;
 
+	spin_lock_irqsave(&iommu->lock, flags);
+	context = iommu_context_addr(iommu, bus, devfn, 0);
+	if (!context) {
+		spin_unlock_irqrestore(&iommu->lock, flags);
+		return;
+	}
+	did_old = context_domain_id(context);
+	spin_unlock_irqrestore(&iommu->lock, flags);
 	clear_context_table(iommu, bus, devfn);
-	iommu->flush.flush_context(iommu, 0, 0, 0,
-					   DMA_CCMD_GLOBAL_INVL);
-	iommu->flush.flush_iotlb(iommu, 0, 0, 0, DMA_TLB_GLOBAL_FLUSH);
+	iommu->flush.flush_context(iommu,
+				   did_old,
+				   (((u16)bus) << 8) | devfn,
+				   DMA_CCMD_MASK_NOBIT,
+				   DMA_CCMD_DEVICE_INVL);
+	iommu->flush.flush_iotlb(iommu,
+				 did_old,
+				 0,
+				 0,
+				 DMA_TLB_DSI_FLUSH);
 }
 
 static inline void unlink_domain_info(struct device_domain_info *info)
-- 
2.7.4

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Thread

[PATCH] intel-iommu: Don't be too aggressive when clearing one context entry Filippo Sironi <sironi@amazon.de> - 2017-08-28 16:20 +0200
  Re: [PATCH] intel-iommu: Don't be too aggressive when clearing one  context entry Joerg Roedel <joro@8bytes.org> - 2017-08-30 15:40 +0200
    Re: [PATCH] intel-iommu: Don't be too aggressive when clearing one  context entry "Sironi, Filippo" <sironi@amazon.de> - 2017-08-31 10:50 +0200
  Re: [PATCH] intel-iommu: Don't be too aggressive when clearing one  context entry Jacob Pan <jacob.jun.pan@linux.intel.com> - 2017-08-30 17:50 +0200
    Re: [PATCH] intel-iommu: Don't be too aggressive when clearing one  context entry "Sironi, Filippo" <sironi@amazon.de> - 2017-08-31 10:50 +0200
  [PATCH v2] iommu/vt-d: Don't be too aggressive when clearing one context entry Filippo Sironi <sironi@amazon.de> - 2017-08-31 11:10 +0200
    Re: [PATCH v2] iommu/vt-d: Don't be too aggressive when clearing one  context entry Joerg Roedel <joro@8bytes.org> - 2017-09-01 11:40 +0200

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