linux-kernel - [PATCH AUTOSEL 5.2 229/249] iommu/arm-smmu-v3: Invalidate ATC when detaching a device

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Message-Id: <20190715134655.4076-229-sashal@kernel.org>
Date:   Mon, 15 Jul 2019 09:46:34 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Jean-Philippe Brucker <jean-philippe.brucker@....com>,
        Manoj Kumar <Manoj.Kumar3@....com>,
        Robin Murphy <Robin.Murphy@....com>,
        Will Deacon <will@...nel.org>, Joerg Roedel <jroedel@...e.de>,
        Sasha Levin <sashal@...nel.org>,
        iommu@...ts.linux-foundation.org
Subject: [PATCH AUTOSEL 5.2 229/249] iommu/arm-smmu-v3: Invalidate ATC when detaching a device

From: Jean-Philippe Brucker <jean-philippe.brucker@....com>

[ Upstream commit 8dd8f005bdd45823fc153ef490239558caf6ff20 ]

We make the invalid assumption in arm_smmu_detach_dev() that the ATC is
clear after calling pci_disable_ats(). For one thing, only enabling the
PCIe ATS capability constitutes an implicit invalidation event, so the
comment was wrong. More importantly, the ATS capability isn't necessarily
disabled by pci_disable_ats() in a PF, if the associated VFs have ATS
enabled. Explicitly invalidate all ATC entries in arm_smmu_detach_dev().
The endpoint cannot form new ATC entries because STE.EATS is clear.

Fixes: 9ce27afc0830 ("iommu/arm-smmu-v3: Add support for PCI ATS")
Reported-by: Manoj Kumar <Manoj.Kumar3@....com>
Reported-by: Robin Murphy <Robin.Murphy@....com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@....com>
Acked-by: Will Deacon <will@...nel.org>
Signed-off-by: Joerg Roedel <jroedel@...e.de>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/iommu/arm-smmu-v3.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 4d5a694f02c2..0fee8f7957ec 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -1884,9 +1884,13 @@ static int arm_smmu_enable_ats(struct arm_smmu_master *master)
 
 static void arm_smmu_disable_ats(struct arm_smmu_master *master)
 {
+	struct arm_smmu_cmdq_ent cmd;
+
 	if (!master->ats_enabled || !dev_is_pci(master->dev))
 		return;
 
+	arm_smmu_atc_inv_to_cmd(0, 0, 0, &cmd);
+	arm_smmu_atc_inv_master(master, &cmd);
 	pci_disable_ats(to_pci_dev(master->dev));
 	master->ats_enabled = false;
 }
@@ -1906,7 +1910,6 @@ static void arm_smmu_detach_dev(struct arm_smmu_master *master)
 	master->domain = NULL;
 	arm_smmu_install_ste_for_dev(master);
 
-	/* Disabling ATS invalidates all ATC entries */
 	arm_smmu_disable_ats(master);
 }
 
-- 
2.20.1