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Subject[PATCH AUTOSEL 5.2 229/249] iommu/arm-smmu-v3: Invalidate ATC when detaching a device
Date
From: Jean-Philippe Brucker <jean-philippe.brucker@arm.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@arm.com>
Reported-by: Robin Murphy <Robin.Murphy@arm.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.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
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