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authorJoerg Roedel <joerg.roedel@amd.com>2009-11-25 15:59:57 +0100
committerJoerg Roedel <joerg.roedel@amd.com>2009-11-27 14:20:33 +0100
commit241000556f751dacd332df6ab2e903a23746e51e (patch)
treeb3dad45997c5e3c9eb754901e24dbca9c959852a /arch/x86
parent657cbb6b6cba0f9c98c5299e0c803b2c0e67ea0a (diff)
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 <joerg.roedel@amd.com>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/include/asm/amd_iommu_types.h1
-rw-r--r--arch/x86/kernel/amd_iommu.c37
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 9eaa27b4686..434e90ed89c 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 3214e8806f9..f5db7d5e444 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);
}