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iommu/vt-d: Identify domains using first level page table

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This checks whether a domain should use the first level page
table for map/unmap and marks it in the domain structure.

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 2020-01-02 08:18:14 +08:00 committed by Joerg Roedel
parent 8e3391cfdc
commit a1948f2e0a
1 changed files with 39 additions and 0 deletions
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39
drivers/iommu/intel-iommu.c
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@ -307,6 +307,14 @@ static int hw_pass_through = 1;
*/
#define DOMAIN_FLAG_LOSE_CHILDREN BIT(1)
/*
* When VT-d works in the scalable mode, it allows DMA translation to
* happen through either first level or second level page table. This
* bit marks that the DMA translation for the domain goes through the
* first level page table, otherwise, it goes through the second level.
*/
#define DOMAIN_FLAG_USE_FIRST_LEVEL BIT(2)
#define for_each_domain_iommu(idx, domain) \
for (idx = 0; idx < g_num_of_iommus; idx++) \
if (domain->iommu_refcnt[idx])
@ -1714,6 +1722,35 @@ static void free_dmar_iommu(struct intel_iommu *iommu)
#endif
}
/*
* Check and return whether first level is used by default for
* DMA translation. Currently, we make it off by setting
* first_level_support = 0, and will change it to -1 after all
* map/unmap paths support first level page table.
*/
static bool first_level_by_default(void)
{
struct dmar_drhd_unit *drhd;
struct intel_iommu *iommu;
static int first_level_support = 0;
if (likely(first_level_support != -1))
return first_level_support;
first_level_support = 1;
rcu_read_lock();
for_each_active_iommu(iommu, drhd) {
if (!sm_supported(iommu) || !ecap_flts(iommu->ecap)) {
first_level_support = 0;
break;
}
}
rcu_read_unlock();
return first_level_support;
}
static struct dmar_domain *alloc_domain(int flags)
{
struct dmar_domain *domain;
@ -1725,6 +1762,8 @@ static struct dmar_domain *alloc_domain(int flags)
memset(domain, 0, sizeof(*domain));
domain->nid = NUMA_NO_NODE;
domain->flags = flags;
if (first_level_by_default())
domain->flags |= DOMAIN_FLAG_USE_FIRST_LEVEL;
domain->has_iotlb_device = false;
INIT_LIST_HEAD(&domain->devices);