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Commit bc7f2ce0 authored by Will Deacon's avatar Will Deacon
Browse files

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: default avatarWill Deacon <will.deacon@arm.com>
parent 25a1c96c

drivers/iommu/arm-smmu-v3.c

+12 −21
Original line number Diff line number Diff line
@@ -1638,6 +1638,17 @@ static int arm_smmu_install_ste_for_group(struct arm_smmu_group *smmu_group) 
	return 0;

}



static void arm_smmu_detach_dev(struct device *dev)

{

	struct arm_smmu_group *smmu_group = arm_smmu_group_get(dev);



	smmu_group->ste.bypass = true;

	if (IS_ERR_VALUE(arm_smmu_install_ste_for_group(smmu_group)))

		dev_warn(dev, "failed to install bypass STE\n");



	smmu_group->domain = NULL;

}



static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)

{

	int ret = 0;
@@ -1650,7 +1661,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) 


	/* Already attached to a different domain? */

	if (smmu_group->domain && smmu_group->domain != smmu_domain)

		return -EEXIST;

		arm_smmu_detach_dev(dev);



	smmu = smmu_group->smmu;

	mutex_lock(&smmu_domain->init_mutex);
@@ -1687,25 +1698,6 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) 
	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_group *smmu_group = arm_smmu_group_get(dev);



	BUG_ON(!smmu_domain);

	BUG_ON(!smmu_group);



	mutex_lock(&smmu_domain->init_mutex);

	BUG_ON(smmu_group->domain != smmu_domain);



	smmu_group->ste.bypass = true;

	if (IS_ERR_VALUE(arm_smmu_install_ste_for_group(smmu_group)))

		dev_warn(dev, "failed to install bypass STE\n");



	smmu_group->domain = NULL;

	mutex_unlock(&smmu_domain->init_mutex);

}



static int arm_smmu_map(struct iommu_domain *domain, unsigned long iova,

			phys_addr_t paddr, size_t size, int prot)

{
@@ -1943,7 +1935,6 @@ static struct iommu_ops arm_smmu_ops = { 
	.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,

	.iova_to_phys		= arm_smmu_iova_to_phys,

drivers/iommu/arm-smmu.c

+14 −19
Original line number Diff line number Diff line
@@ -1131,6 +1131,16 @@ static void arm_smmu_domain_remove_master(struct arm_smmu_domain *smmu_domain, 
	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 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) 
		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 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) 
	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 @@ static struct iommu_ops arm_smmu_ops = { 
	.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,