diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/iommu/intel/iommu.c | 28 |
1 files changed, 25 insertions, 3 deletions
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index b9d058c27568..b155c7af7d15 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -390,14 +390,36 @@ static inline int domain_pfn_supported(struct dmar_domain *domain, return !(addr_width < BITS_PER_LONG && pfn >> addr_width); } +/* + * Calculate the Supported Adjusted Guest Address Widths of an IOMMU. + * Refer to 11.4.2 of the VT-d spec for the encoding of each bit of + * the returned SAGAW. + */ +static unsigned long __iommu_calculate_sagaw(struct intel_iommu *iommu) +{ + unsigned long fl_sagaw, sl_sagaw; + + fl_sagaw = BIT(2) | (cap_fl1gp_support(iommu->cap) ? BIT(3) : 0); + sl_sagaw = cap_sagaw(iommu->cap); + + /* Second level only. */ + if (!sm_supported(iommu) || !ecap_flts(iommu->ecap)) + return sl_sagaw; + + /* First level only. */ + if (!ecap_slts(iommu->ecap)) + return fl_sagaw; + + return fl_sagaw & sl_sagaw; +} + static int __iommu_calculate_agaw(struct intel_iommu *iommu, int max_gaw) { unsigned long sagaw; int agaw; - sagaw = cap_sagaw(iommu->cap); - for (agaw = width_to_agaw(max_gaw); - agaw >= 0; agaw--) { + sagaw = __iommu_calculate_sagaw(iommu); + for (agaw = width_to_agaw(max_gaw); agaw >= 0; agaw--) { if (test_bit(agaw, &sagaw)) break; } |