From bc7f2ce0a7b54ba7703f81995fe434f0926424d2 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Wed, 17 Feb 2016 17:41:57 +0000 Subject: [PATCH] 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 --- drivers/iommu/arm-smmu-v3.c | 33 ++++++++++++--------------------- drivers/iommu/arm-smmu.c | 33 ++++++++++++++------------------- 2 files changed, 26 insertions(+), 40 deletions(-) diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c index f003b3ab646b..d96d45ddf500 100644 --- a/drivers/iommu/arm-smmu-v3.c +++ b/drivers/iommu/arm-smmu-v3.c @@ -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 @@ out_unlock: 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, diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index 7012531abe62..f21332a15040 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -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,