From: Will Deacon <will@kernel.org>
To: iommu@lists.linux-foundation.org
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>,
Robin Murphy <robin.murphy@arm.com>,
stable@vger.kernel.org, Will Deacon <will@kernel.org>
Subject: [PATCH v2 2/8] iommu/arm-smmu-v3: Disable detection of ATS and PRI
Date: Wed, 21 Aug 2019 16:17:43 +0100 [thread overview]
Message-ID: <20190821151749.23743-3-will@kernel.org> (raw)
In-Reply-To: <20190821151749.23743-1-will@kernel.org>
Detecting the ATS capability of the SMMU at probe time introduces a
spinlock into the ->unmap() fast path, even when ATS is not actually
in use. Furthermore, the ATC invalidation that exists is broken, as it
occurs before invalidation of the main SMMU TLB which leaves a window
where the ATC can be repopulated with stale entries.
Given that ATS is both a new feature and a specialist sport, disable it
for now whilst we fix it properly in subsequent patches. Since PRI
requires ATS, disable that too.
Cc: <stable@vger.kernel.org>
Fixes: 9ce27afc0830 ("iommu/arm-smmu-v3: Add support for PCI ATS")
Signed-off-by: Will Deacon <will@kernel.org>
---
drivers/iommu/arm-smmu-v3.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 3402b1bc8e94..7a368059cd7d 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -3295,11 +3295,13 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
}
/* Boolean feature flags */
+#if 0 /* ATS invalidation is slow and broken */
if (IS_ENABLED(CONFIG_PCI_PRI) && reg & IDR0_PRI)
smmu->features |= ARM_SMMU_FEAT_PRI;
if (IS_ENABLED(CONFIG_PCI_ATS) && reg & IDR0_ATS)
smmu->features |= ARM_SMMU_FEAT_ATS;
+#endif
if (reg & IDR0_SEV)
smmu->features |= ARM_SMMU_FEAT_SEV;
--
2.11.0
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2019-08-21 15:19 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-21 15:17 [PATCH v2 0/8] Sort out SMMUv3 ATC invalidation and locking Will Deacon
2019-08-21 15:17 ` [PATCH v2 1/8] iommu/arm-smmu-v3: Document ordering guarantees of command insertion Will Deacon
2019-08-21 15:17 ` Will Deacon [this message]
2019-08-21 15:36 ` [PATCH v2 2/8] iommu/arm-smmu-v3: Disable detection of ATS and PRI Robin Murphy
2019-08-21 15:17 ` [PATCH v2 3/8] iommu/arm-smmu-v3: Remove boolean bitfield for 'ats_enabled' flag Will Deacon
2019-08-21 15:17 ` [PATCH v2 4/8] iommu/arm-smmu-v3: Don't issue CMD_SYNC for zero-length invalidations Will Deacon
2019-08-21 15:17 ` [PATCH v2 5/8] iommu/arm-smmu-v3: Rework enabling/disabling of ATS for PCI masters Will Deacon
2019-08-21 15:50 ` Robin Murphy
2019-08-21 15:17 ` [PATCH v2 6/8] iommu/arm-smmu-v3: Fix ATC invalidation ordering wrt main TLBs Will Deacon
2019-08-21 16:25 ` Robin Murphy
2019-08-21 15:17 ` [PATCH v2 7/8] iommu/arm-smmu-v3: Avoid locking on invalidation path when not using ATS Will Deacon
2019-08-22 12:36 ` Robin Murphy
2019-08-21 15:17 ` [PATCH v2 8/8] Revert "iommu/arm-smmu-v3: Disable detection of ATS and PRI" Will Deacon
2020-01-02 17:44 ` arm-smmu-v3 high cpu usage for NVMe John Garry
2020-03-18 20:53 ` Will Deacon
2020-03-19 12:54 ` John Garry
2020-03-19 18:43 ` Jean-Philippe Brucker
2020-03-20 10:41 ` John Garry
2020-03-20 11:18 ` Jean-Philippe Brucker
2020-03-20 16:20 ` John Garry
2020-03-20 16:33 ` Marc Zyngier
2020-03-23 9:03 ` John Garry
2020-03-23 9:16 ` Marc Zyngier
2020-03-24 9:18 ` John Garry
2020-03-24 10:43 ` Marc Zyngier
2020-03-24 11:55 ` John Garry
2020-03-24 12:07 ` Robin Murphy
2020-03-24 12:37 ` John Garry
2020-03-25 15:31 ` John Garry
2020-05-22 14:52 ` John Garry
2020-05-25 5:57 ` Song Bao Hua (Barry Song)
[not found] ` <482c00d5-8e6d-1484-820e-1e89851ad5aa@huawei.com>
2020-04-06 15:11 ` John Garry
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190821151749.23743-3-will@kernel.org \
--to=will@kernel.org \
--cc=iommu@lists.linux-foundation.org \
--cc=jean-philippe@linaro.org \
--cc=robin.murphy@arm.com \
--cc=stable@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).