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x86/amd-iommu: Add passthrough mode initialization functions

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When iommu=pt is passed on kernel command line the devices
should run untranslated. This requires the allocation of a
special domain for that purpose. This patch implements the
allocation and initialization path for iommu=pt.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This commit is contained in:
Joerg Roedel
2009-08-26 15:26:30 +02:00
parent 2650815fb0
commit 0feae533dd
3 changed files with 69 additions and 8 deletions
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72
arch/x86/kernel/amd_iommu.c
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@@ -41,6 +41,12 @@ static DEFINE_RWLOCK(amd_iommu_devtable_lock);
static LIST_HEAD(iommu_pd_list);
static DEFINE_SPINLOCK(iommu_pd_list_lock);
/*
* Domain for untranslated devices - only allocated
* if iommu=pt passed on kernel cmd line.
*/
static struct protection_domain *pt_domain;
#ifdef CONFIG_IOMMU_API
static struct iommu_ops amd_iommu_ops;
#endif
@@ -1067,9 +1073,9 @@ static struct protection_domain *domain_for_device(u16 devid)
* If a device is not yet associated with a domain, this function does
* assigns it visible for the hardware
*/
static void attach_device(struct amd_iommu *iommu,
struct protection_domain *domain,
u16 devid)
static void __attach_device(struct amd_iommu *iommu,
struct protection_domain *domain,
u16 devid)
{
unsigned long flags;
u64 pte_root = virt_to_phys(domain->pt_root);
@@ -1087,12 +1093,19 @@ static void attach_device(struct amd_iommu *iommu,
amd_iommu_pd_table[devid] = domain;
write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
}
/*
* We might boot into a crash-kernel here. The crashed kernel
* left the caches in the IOMMU dirty. So we have to flush
* here to evict all dirty stuff.
*/
static void attach_device(struct amd_iommu *iommu,
struct protection_domain *domain,
u16 devid)
{
__attach_device(iommu, domain, devid);
/*
* We might boot into a crash-kernel here. The crashed kernel
* left the caches in the IOMMU dirty. So we have to flush
* here to evict all dirty stuff.
*/
iommu_queue_inv_dev_entry(iommu, devid);
iommu_flush_tlb_pde(iommu, domain->id);
}
@@ -2219,3 +2232,46 @@ static struct iommu_ops amd_iommu_ops = {
.domain_has_cap = amd_iommu_domain_has_cap,
};
/*****************************************************************************
*
* The next functions do a basic initialization of IOMMU for pass through
* mode
*
* In passthrough mode the IOMMU is initialized and enabled but not used for
* DMA-API translation.
*
*****************************************************************************/
int __init amd_iommu_init_passthrough(void)
{
struct pci_dev *dev = NULL;
u16 devid, devid2;
/* allocate passthroug domain */
pt_domain = protection_domain_alloc();
if (!pt_domain)
return -ENOMEM;
pt_domain->mode |= PAGE_MODE_NONE;
while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
struct amd_iommu *iommu;
devid = calc_devid(dev->bus->number, dev->devfn);
if (devid > amd_iommu_last_bdf)
continue;
devid2 = amd_iommu_alias_table[devid];
iommu = amd_iommu_rlookup_table[devid2];
if (!iommu)
continue;
__attach_device(iommu, pt_domain, devid);
__attach_device(iommu, pt_domain, devid2);
}
pr_info("AMD-Vi: Initialized for Passthrough Mode\n");
return 0;
}