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iommu/vt-d: Handle 32bit device with identity default domain

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The iommu driver doesn't know whether the bit width of a PCI
device is sufficient for access to the whole system memory.
Hence, the driver checks this when the driver calls into the
dma APIs. If a device is using an identity domain, but the
bit width is less than the system requirement, we need to use
a dma domain instead. This also applies after we delegated
the domain life cycle management to the upper layer.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Lu Baolu 2019-05-25 13:41:30 +08:00 committed by Joerg Roedel
parent 942067f1b6
commit 98b2fffb5e
1 changed files with 22 additions and 33 deletions
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55
drivers/iommu/intel-iommu.c
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@ -2984,25 +2984,6 @@ static int device_def_domain_type(struct device *dev, int startup)
return IOMMU_DOMAIN_DMA;
}
/*
* At boot time, we don't yet know if devices will be 64-bit capable.
* Assume that they will — if they turn out not to be, then we can
* take them out of the 1:1 domain later.
*/
if (!startup) {
/*
* If the device's dma_mask is less than the system's memory
* size then this is not a candidate for identity mapping.
*/
u64 dma_mask = *dev->dma_mask;
if (dev->coherent_dma_mask &&
dev->coherent_dma_mask < dma_mask)
dma_mask = dev->coherent_dma_mask;
return dma_mask >= dma_get_required_mask(dev);
}
return (iommu_identity_mapping & IDENTMAP_ALL) ?
IOMMU_DOMAIN_IDENTITY : 0;
}
@ -3614,14 +3595,19 @@ out:
/* Check if the dev needs to go through non-identity map and unmap process.*/
static bool iommu_need_mapping(struct device *dev)
{
int found;
int ret;
if (iommu_dummy(dev))
return false;
found = identity_mapping(dev);
if (found) {
if (iommu_should_identity_map(dev, 0))
ret = identity_mapping(dev);
if (ret) {
u64 dma_mask = *dev->dma_mask;
if (dev->coherent_dma_mask && dev->coherent_dma_mask < dma_mask)
dma_mask = dev->coherent_dma_mask;
if (dma_mask >= dma_get_required_mask(dev))
return false;
/*
@ -3629,17 +3615,20 @@ static bool iommu_need_mapping(struct device *dev)
* non-identity mapping.
*/
dmar_remove_one_dev_info(dev);
dev_info(dev, "32bit DMA uses non-identity mapping\n");
} else {
/*
* In case of a detached 64 bit DMA device from vm, the device
* is put into si_domain for identity mapping.
*/
if (iommu_should_identity_map(dev, 0) &&
!domain_add_dev_info(si_domain, dev)) {
dev_info(dev, "64bit DMA uses identity mapping\n");
return false;
ret = iommu_request_dma_domain_for_dev(dev);
if (ret) {
struct iommu_domain *domain;
struct dmar_domain *dmar_domain;
domain = iommu_get_domain_for_dev(dev);
if (domain) {
dmar_domain = to_dmar_domain(domain);
dmar_domain->flags |= DOMAIN_FLAG_LOSE_CHILDREN;
}
get_valid_domain_for_dev(dev);
}
dev_info(dev, "32bit DMA uses non-identity mapping\n");
}
return true;