On Wed, Dec 13, 2023 at 05:17:59PM +0000, Robin Murphy wrote:
> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> index 27a167f4cd3e..d808c8dcf5cb 100644
> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -1724,25 +1724,20 @@ static const struct dma_map_ops iommu_dma_ops = {
> .opt_mapping_size = iommu_dma_opt_mapping_size,
> };
>
> -/*
> - * The IOMMU core code allocates the default DMA domain, which the underlying
> - * IOMMU driver needs to support via the dma-iommu layer.
> - */
> -void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 dma_limit)
> +void iommu_setup_dma_ops(struct device *dev)
> {
> struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
>
> - if (!domain)
> - goto out_err;
> + if (dev_is_pci(dev))
> + dev->iommu->pci_32bit_workaround = !iommu_dma_forcedac;
>
> - /*
> - * The IOMMU core code allocates the default DMA domain, which the
> - * underlying IOMMU driver needs to support via the dma-iommu layer.
> - */
> if (iommu_is_dma_domain(domain)) {
...
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index 824989874dee..43f630d0530e 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -560,10 +560,10 @@ static int __iommu_probe_device(struct device *dev, struct list_head *group_list
> if (list_empty(&group->entry))
> list_add_tail(&group->entry, group_list);
> }
> - mutex_unlock(&group->mutex);
>
> - if (dev_is_pci(dev))
> - iommu_dma_set_pci_32bit_workaround(dev);
> + iommu_setup_dma_ops(dev);
With Intel VT-d (QEMU emulation) I get a crash in iommu_setup_dma_ops()
because at this point group->domain and group->default_domain are still
NULL, group_list is non-NULL.
No problem with x86 virtio-iommu, it goes through
iommu_setup_default_domain() earlier in the function. Arm virtio-iommu is
fine too.
Thanks,
Jean
