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From: Zhen Lei <thunder.leizhen@huawei.com>
To: Robin Murphy <robin.murphy@arm.com>,
	Will Deacon <will.deacon@arm.com>, Joerg Roedel <joro@8bytes.org>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	iommu <iommu@lists.linux-foundation.org>,
	linux-kernel <linux-kernel@vger.kernel.org>
Cc: Zhen Lei <thunder.leizhen@huawei.com>,
	LinuxArm <linuxarm@huawei.com>, Hanjun Guo <guohanjun@huawei.com>,
	Libin <huawei.libin@huawei.com>
Subject: [PATCH v2 0/2] bugfix and optimization about CMD_SYNC
Date: Thu, 9 Aug 2018 19:48:51 +0800	[thread overview]
Message-ID: <1533815333-17320-1-git-send-email-thunder.leizhen@huawei.com> (raw)

v1->v2:
1. move the call to arm_smmu_cmdq_build_cmd into the critical section,
   and keep itself unchange.
2. Although patch2 can make sure no two CMD_SYNCs will be adjacent,
but patch1 is still needed, see below:

cpu0			cpu1			cpu2
msidata=0
			msidata=1
			insert cmd1
						insert a TLBI command
insert cmd0
			smmu execute cmd1
						smmu execute TLBI
smmu execute cmd0
			poll timeout, because msidata=1 is overridden by
			cmd0, that means VAL=0, sync_idx=1.

Zhen Lei (2):
  iommu/arm-smmu-v3: fix unexpected CMD_SYNC timeout
  iommu/arm-smmu-v3: avoid redundant CMD_SYNCs if possible

 drivers/iommu/arm-smmu-v3.c | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

-- 
1.8.3



             reply	other threads:[~2018-08-09 11:50 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-09 11:48 Zhen Lei [this message]
2018-08-09 11:48 ` [PATCH v2 1/2] iommu/arm-smmu-v3: fix unexpected CMD_SYNC timeout Zhen Lei
2018-08-09 11:48 ` [PATCH v2 2/2] iommu/arm-smmu-v3: avoid redundant CMD_SYNCs if possible Zhen Lei
2018-08-09 12:02   ` Robin Murphy

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