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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>
This commit is contained in:
Joerg Roedel 2009-11-25 15:59:57 +01:00
parent 657cbb6b6c
commit 241000556f
2 changed files with 30 additions and 8 deletions
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1
arch/x86/include/asm/amd_iommu_types.h
View File

@ -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 */
};
/*

37
arch/x86/kernel/amd_iommu.c
View File

@ -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);
}