Hi,
On 12/21/19 11:03 PM, Tom Murphy wrote:
@@ -5618,9 +5583,13 @@ static int intel_iommu_add_device(struct device *dev) struct iommu_domain *domain; struct intel_iommu *iommu; struct iommu_group *group;
u64 dma_mask = *dev->dma_mask; u8 bus, devfn; int ret;
if (dev->coherent_dma_mask && dev->coherent_dma_mask < dma_mask)
dma_mask = dev->coherent_dma_mask;iommu = device_to_iommu(dev, &bus, &devfn); if (!iommu) return -ENODEV;
@@ -5640,7 +5609,12 @@ static int intel_iommu_add_device(struct device *dev) domain = iommu_get_domain_for_dev(dev); dmar_domain = to_dmar_domain(domain); if (domain->type == IOMMU_DOMAIN_DMA) {
if (device_def_domain_type(dev) == IOMMU_DOMAIN_IDENTITY) {
/** We check dma_mask >= dma_get_required_mask(dev) because* 32 bit DMA falls back to non-identity mapping.*/if (device_def_domain_type(dev) == IOMMU_DOMAIN_IDENTITY &&dma_mask >= dma_get_required_mask(dev)) { ret = iommu_request_dm_for_dev(dev); if (ret) { dmar_remove_one_dev_info(dev);
dev->dma_mask is set to 32bit by default. During loading driver, it sets the real dma_mask with dma_set_mask() according to the real capability. Here you will always see 32bit dma_mask for each device.
Best regards, baolu