From: Lu Baolu <baolu.lu@linux.intel.com>
To: Jacob jun Pan <jacob.jun.pan@intel.com>,
Kevin Tian <kevin.tian@intel.com>,
Ashok Raj <ashok.raj@intel.com>, Liu Yi L <yi.l.liu@intel.com>
Cc: iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
Lu Baolu <baolu.lu@linux.intel.com>,
Jacob Pan <jacob.jun.pan@linux.intel.com>
Subject: [PATCH 2/3] iommu/vt-d: Drop stop marker messages
Date: Sat, 16 Apr 2022 20:30:48 +0800 [thread overview]
Message-ID: <20220416123049.879969-3-baolu.lu@linux.intel.com> (raw)
In-Reply-To: <20220416123049.879969-1-baolu.lu@linux.intel.com>
The VT-d driver explicitly drains the pending page requests when a CPU
page table (represented by a mm struct) is unbound from a PASID according
to the procedures defined in the VT-d spec. Hence, there's no need to
report the stop-marker message in prq_event_thread(). The stop marker
messages do not need a response. This drops stop marker messages silently
if any of them is found in the page request queue.
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
---
drivers/iommu/intel/svm.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index d88af37c20ef..d1c42dfae6ca 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -758,6 +758,10 @@ static irqreturn_t prq_event_thread(int irq, void *d)
goto bad_req;
}
+ /* Drop Stop Marker message. No need for a response. */
+ if (unlikely(req->lpig && !req->rd_req && !req->wr_req))
+ goto prq_advance;
+
if (!svm || svm->pasid != req->pasid) {
/*
* It can't go away, because the driver is not permitted
--
2.25.1
next prev parent reply other threads:[~2022-04-16 12:33 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-16 12:30 [PATCH 0/3] iommu/vt-d: Some fine tuning of SVA Lu Baolu
2022-04-16 12:30 ` [PATCH 1/3] iommu/vt-d: Set PGSNP bit in pasid table entry for sva binding Lu Baolu
2022-04-18 6:56 ` Tian, Kevin
2022-04-18 11:28 ` Lu Baolu
2022-04-16 12:30 ` Lu Baolu [this message]
2022-04-18 6:58 ` [PATCH 2/3] iommu/vt-d: Drop stop marker messages Tian, Kevin
2022-04-18 11:37 ` Lu Baolu
2022-04-16 12:30 ` [PATCH 3/3] iommu/vt-d: Size Page Request Queue to avoid overflow condition Lu Baolu
2022-04-18 7:00 ` Tian, Kevin
2022-04-18 11:44 ` Lu Baolu
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