diff options
Diffstat (limited to 'drivers/iommu/intel/iommu.c')
| -rw-r--r-- | drivers/iommu/intel/iommu.c | 32 |
1 files changed, 31 insertions, 1 deletions
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index f665322a0991..06b00b5363d8 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -5440,6 +5440,36 @@ intel_iommu_domain_set_attr(struct iommu_domain *domain, return ret; } +static bool domain_use_flush_queue(void) +{ + struct dmar_drhd_unit *drhd; + struct intel_iommu *iommu; + bool r = true; + + if (intel_iommu_strict) + return false; + + /* + * The flush queue implementation does not perform page-selective + * invalidations that are required for efficient TLB flushes in virtual + * environments. The benefit of batching is likely to be much lower than + * the overhead of synchronizing the virtual and physical IOMMU + * page-tables. + */ + rcu_read_lock(); + for_each_active_iommu(iommu, drhd) { + if (!cap_caching_mode(iommu->cap)) + continue; + + pr_warn_once("IOMMU batching is disabled due to virtualization"); + r = false; + break; + } + rcu_read_unlock(); + + return r; +} + static int intel_iommu_domain_get_attr(struct iommu_domain *domain, enum iommu_attr attr, void *data) @@ -5450,7 +5480,7 @@ intel_iommu_domain_get_attr(struct iommu_domain *domain, case IOMMU_DOMAIN_DMA: switch (attr) { case DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE: - *(int *)data = !intel_iommu_strict; + *(int *)data = domain_use_flush_queue(); return 0; default: return -ENODEV; |