From: Jason Gunthorpe jgg@nvidia.com
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.... Signed-off-by: Will Deacon will@kernel.org Signed-off-by: Kunkun Jiang jiangkunkun@huawei.com --- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c index 0648d1ab3e3a..4792600019d1 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c @@ -2723,7 +2723,6 @@ 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) @@ -2737,11 +2736,6 @@ 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 @@ -3108,9 +3102,18 @@ 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);