From 241000556f751dacd332df6ab2e903a23746e51e Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Wed, 25 Nov 2009 15:59:57 +0100 Subject: [PATCH] x86/amd-iommu: Add device bind reference counting This patch adds a reference count to each device to count how often the device was bound to that domain. This is important for single devices that act as an alias for a number of others. These devices must stay bound to their domains until all devices that alias to it are unbound from the same domain. Signed-off-by: Joerg Roedel --- arch/x86/include/asm/amd_iommu_types.h | 1 + arch/x86/kernel/amd_iommu.c | 37 ++++++++++++++++++++------ 2 files changed, 30 insertions(+), 8 deletions(-) diff --git a/arch/x86/include/asm/amd_iommu_types.h b/arch/x86/include/asm/amd_iommu_types.h index 9eaa27b46860..434e90ed89c5 100644 --- a/arch/x86/include/asm/amd_iommu_types.h +++ b/arch/x86/include/asm/amd_iommu_types.h @@ -253,6 +253,7 @@ struct protection_domain { struct iommu_dev_data { struct device *alias; /* The Alias Device */ struct protection_domain *domain; /* Domain the device is bound to */ + atomic_t bind; /* Domain attach reverent count */ }; /* diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c index 3214e8806f95..f5db7d5e444e 100644 --- a/arch/x86/kernel/amd_iommu.c +++ b/arch/x86/kernel/amd_iommu.c @@ -152,6 +152,8 @@ static int iommu_init_device(struct device *dev) if (pdev) dev_data->alias = &pdev->dev; + atomic_set(&dev_data->bind, 0); + dev->archdata.iommu = dev_data; @@ -1403,10 +1405,13 @@ static int __attach_device(struct device *dev, return -EBUSY; /* Do real assignment */ - if (alias != devid && - alias_data->domain == NULL) { - alias_data->domain = domain; - set_dte_entry(alias, domain); + if (alias != devid) { + if (alias_data->domain == NULL) { + alias_data->domain = domain; + set_dte_entry(alias, domain); + } + + atomic_inc(&alias_data->bind); } if (dev_data->domain == NULL) { @@ -1414,6 +1419,8 @@ static int __attach_device(struct device *dev, set_dte_entry(devid, domain); } + atomic_inc(&dev_data->bind); + /* ready */ spin_unlock(&domain->lock); @@ -1449,20 +1456,34 @@ static int attach_device(struct device *dev, */ static void __detach_device(struct device *dev) { - u16 devid = get_device_id(dev); + u16 devid = get_device_id(dev), alias; struct amd_iommu *iommu = amd_iommu_rlookup_table[devid]; struct iommu_dev_data *dev_data = get_dev_data(dev); + struct iommu_dev_data *alias_data; BUG_ON(!iommu); - clear_dte_entry(devid); - dev_data->domain = NULL; + devid = get_device_id(dev); + alias = get_device_id(dev_data->alias); + + if (devid != alias) { + alias_data = get_dev_data(dev_data->alias); + if (atomic_dec_and_test(&alias_data->bind)) { + clear_dte_entry(alias); + alias_data->domain = NULL; + } + } + + if (atomic_dec_and_test(&dev_data->bind)) { + clear_dte_entry(devid); + dev_data->domain = NULL; + } /* * If we run in passthrough mode the device must be assigned to the * passthrough domain if it is detached from any other domain */ - if (iommu_pass_through) + if (iommu_pass_through && dev_data->domain == NULL) __attach_device(dev, pt_domain); }