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AMD IOMMU: don't assign preallocated protection domains to devices 

In isolation mode the protection domains for the devices are
preallocated and preassigned. This is bad if a device should be passed
to a virtualization guest because the IOMMU code does not know if it is
in use by a driver. This patch changes the code to assign the device to
the preallocated domain only if there are dma mapping requests for it.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Joerg Roedel 2008-09-11 10:24:48 +02:00 committed by Ingo Molnar
parent b39ba6ad00
commit bd60b735c6
2 changed files with 44 additions and 5 deletions
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43
arch/x86/kernel/amd_iommu.c
View File

@ -33,6 +33,10 @@
static DEFINE_RWLOCK(amd_iommu_devtable_lock);
/* A list of preallocated protection domains */
static LIST_HEAD(iommu_pd_list);
static DEFINE_SPINLOCK(iommu_pd_list_lock);
/*
* general struct to manage commands send to an IOMMU
*/
@ -663,6 +667,7 @@ static struct dma_ops_domain *dma_ops_domain_alloc(struct amd_iommu *iommu,
dma_dom->next_bit = 0;
dma_dom->need_flush = false;
dma_dom->target_dev = 0xffff;
/* Intialize the exclusion range if necessary */
if (iommu->exclusion_start &&
@ -768,6 +773,33 @@ static bool check_device(struct device *dev)
return true;
}
/*
* In this function the list of preallocated protection domains is traversed to
* find the domain for a specific device
*/
static struct dma_ops_domain *find_protection_domain(u16 devid)
{
struct dma_ops_domain *entry, *ret = NULL;
unsigned long flags;
if (list_empty(&iommu_pd_list))
return NULL;
spin_lock_irqsave(&iommu_pd_list_lock, flags);
list_for_each_entry(entry, &iommu_pd_list, list) {
if (entry->target_dev == devid) {
ret = entry;
list_del(&ret->list);
break;
}
}
spin_unlock_irqrestore(&iommu_pd_list_lock, flags);
return ret;
}
/*
* In the dma_ops path we only have the struct device. This function
* finds the corresponding IOMMU, the protection domain and the
@ -803,9 +835,11 @@ static int get_device_resources(struct device *dev,
*iommu = amd_iommu_rlookup_table[*bdf];
if (*iommu == NULL)
return 0;
dma_dom = (*iommu)->default_dom;
*domain = domain_for_device(*bdf);
if (*domain == NULL) {
dma_dom = find_protection_domain(*bdf);
if (!dma_dom)
dma_dom = (*iommu)->default_dom;
*domain = &dma_dom->domain;
set_device_domain(*iommu, *domain, *bdf);
printk(KERN_INFO "AMD IOMMU: Using protection domain %d for "
@ -1257,10 +1291,9 @@ void prealloc_protection_domains(void)
if (!dma_dom)
continue;
init_unity_mappings_for_device(dma_dom, devid);
set_device_domain(iommu, &dma_dom->domain, devid);
printk(KERN_INFO "AMD IOMMU: Allocated domain %d for device ",
dma_dom->domain.id);
print_devid(devid, 1);
dma_dom->target_dev = devid;
list_add_tail(&dma_dom->list, &iommu_pd_list);
}
}

6
include/asm-x86/amd_iommu_types.h
View File

@ -227,6 +227,12 @@ struct dma_ops_domain {
/* This will be set to true when TLB needs to be flushed */
bool need_flush;
/*
* if this is a preallocated domain, keep the device for which it was
* preallocated in this variable
*/
u16 target_dev;
};
/*