iommu/arm-smmu: Don't fail device attach if already attached to a domain
The ARM SMMU attach_dev implementations returns -EEXIST if the device
being attached is already attached to a domain. This doesn't play nicely
with the default domain, resulting in splats such as:
WARNING: at drivers/iommu/iommu.c:1257
Modules linked in:
CPU: 3 PID: 1939 Comm: virtio-net-tx Tainted: G S 4.5.0-rc4+ #1
Hardware name: FVP Base (DT)
task: ffffffc87a9d0000 ti: ffffffc07a278000 task.ti: ffffffc07a278000
PC is at __iommu_detach_group+0x68/0xe8
LR is at __iommu_detach_group+0x48/0xe8
This patch fixes the problem by forcefully detaching the device from
its old domain, if present, when attaching to a new one. The unused
->detach_dev callback is also removed the iommu_ops structures.
Signed-off-by: Will Deacon <will.deacon@arm.com>
diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 7012531..f21332a 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1131,6 +1131,16 @@
arm_smmu_master_free_smrs(smmu, cfg);
}
+static void arm_smmu_detach_dev(struct device *dev,
+ struct arm_smmu_master_cfg *cfg)
+{
+ struct iommu_domain *domain = dev->archdata.iommu;
+ struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+
+ dev->archdata.iommu = NULL;
+ arm_smmu_domain_remove_master(smmu_domain, cfg);
+}
+
static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
{
int ret;
@@ -1144,11 +1154,6 @@
return -ENXIO;
}
- if (dev->archdata.iommu) {
- dev_err(dev, "already attached to IOMMU domain\n");
- return -EEXIST;
- }
-
/* Ensure that the domain is finalised */
ret = arm_smmu_init_domain_context(domain, smmu);
if (IS_ERR_VALUE(ret))
@@ -1170,25 +1175,16 @@
if (!cfg)
return -ENODEV;
+ /* Detach the dev from its current domain */
+ if (dev->archdata.iommu)
+ arm_smmu_detach_dev(dev, cfg);
+
ret = arm_smmu_domain_add_master(smmu_domain, cfg);
if (!ret)
dev->archdata.iommu = domain;
return ret;
}
-static void arm_smmu_detach_dev(struct iommu_domain *domain, struct device *dev)
-{
- struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
- struct arm_smmu_master_cfg *cfg;
-
- cfg = find_smmu_master_cfg(dev);
- if (!cfg)
- return;
-
- dev->archdata.iommu = NULL;
- arm_smmu_domain_remove_master(smmu_domain, cfg);
-}
-
static int arm_smmu_map(struct iommu_domain *domain, unsigned long iova,
phys_addr_t paddr, size_t size, int prot)
{
@@ -1464,7 +1460,6 @@
.domain_alloc = arm_smmu_domain_alloc,
.domain_free = arm_smmu_domain_free,
.attach_dev = arm_smmu_attach_dev,
- .detach_dev = arm_smmu_detach_dev,
.map = arm_smmu_map,
.unmap = arm_smmu_unmap,
.map_sg = default_iommu_map_sg,