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Diffstat (limited to 'drivers/pci/intel-iommu.c')
| -rw-r--r-- | drivers/pci/intel-iommu.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c index 9dca689215eb..3ecfa2304c2c 100644 --- a/drivers/pci/intel-iommu.c +++ b/drivers/pci/intel-iommu.c @@ -362,6 +362,28 @@ void free_iova_mem(struct iova *iova) kmem_cache_free(iommu_iova_cache, iova); } + +static inline int width_to_agaw(int width); + +/* calculate agaw for each iommu. + * "SAGAW" may be different across iommus, use a default agaw, and + * get a supported less agaw for iommus that don't support the default agaw. + */ +int iommu_calculate_agaw(struct intel_iommu *iommu) +{ + unsigned long sagaw; + int agaw = -1; + + sagaw = cap_sagaw(iommu->cap); + for (agaw = width_to_agaw(DEFAULT_DOMAIN_ADDRESS_WIDTH); + agaw >= 0; agaw--) { + if (test_bit(agaw, &sagaw)) + break; + } + + return agaw; +} + /* in native case, each domain is related to only one iommu */ static struct intel_iommu *domain_get_iommu(struct dmar_domain *domain) { |