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iommu/arm-smmu-v3: Do not change the STE twice during arm_smmu_attach_dev()

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This was needed because the STE code required the STE to be in
ABORT/BYPASS inorder to program a cdtable or S2 STE. Now that the STE code
can automatically handle all transitions we can remove this step
from the attach_dev flow.

A few small bugs exist because of this:

1) If the core code does BLOCKED -> UNMANAGED with disable_bypass=false
   then there will be a moment where the STE points at BYPASS. Since
   this can be done by VFIO/IOMMUFD it is a small security race.

2) If the core code does IDENTITY -> DMA then any IOMMU_RESV_DIRECT
   regions will temporarily become BLOCKED. We'd like drivers to
   work in a way that allows IOMMU_RESV_DIRECT to be continuously
   functional during these transitions.

Make arm_smmu_release_device() put the STE back to the correct
ABORT/BYPASS setting. Fix a bug where a IOMMU_RESV_DIRECT was ignored on
this path.

As noted before the reordering of the linked list/STE/CD changes is OK
against concurrent arm_smmu_share_asid() because of the
arm_smmu_asid_lock.

Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Moritz Fischer <moritzf@google.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/7-v6-96275f25c39d+2d4-smmuv3_newapi_p1_jgg@nvidia.com
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Jason Gunthorpe 2024-02-26 13:07:18 -04:00 committed by Will Deacon
parent 65547275d7
commit 8c73c32c83
1 changed files with 9 additions and 6 deletions
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15
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
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@ -2509,7 +2509,6 @@ static void arm_smmu_disable_pasid(struct arm_smmu_master *master)
static void arm_smmu_detach_dev(struct arm_smmu_master *master)
{
unsigned long flags;
struct arm_smmu_ste target;
struct arm_smmu_domain *smmu_domain = master->domain;
if (!smmu_domain)
@ -2523,11 +2522,6 @@ static void arm_smmu_detach_dev(struct arm_smmu_master *master)
master->domain = NULL;
master->ats_enabled = false;
if (disable_bypass)
arm_smmu_make_abort_ste(&target);
else
arm_smmu_make_bypass_ste(&target);
arm_smmu_install_ste_for_dev(master, &target);
/*
* Clearing the CD entry isn't strictly required to detach the domain
* since the table is uninstalled anyway, but it helps avoid confusion
@ -2875,9 +2869,18 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev)
static void arm_smmu_release_device(struct device *dev)
{
struct arm_smmu_master *master = dev_iommu_priv_get(dev);
struct arm_smmu_ste target;
if (WARN_ON(arm_smmu_master_sva_enabled(master)))
iopf_queue_remove_device(master->smmu->evtq.iopf, dev);
/* Put the STE back to what arm_smmu_init_strtab() sets */
if (disable_bypass && !dev->iommu->require_direct)
arm_smmu_make_abort_ste(&target);
else
arm_smmu_make_bypass_ste(&target);
arm_smmu_install_ste_for_dev(master, &target);
arm_smmu_detach_dev(master);
arm_smmu_disable_pasid(master);
arm_smmu_remove_master(master);