Commit f0f07a84 authored by Jean-Philippe Brucker's avatar Jean-Philippe Brucker Committed by Joerg Roedel
Browse files

iommu/virtio: Support bypass domains 



The VIRTIO_IOMMU_F_BYPASS_CONFIG feature adds a new flag to the ATTACH
request, that creates a bypass domain. Use it to enable identity
domains.

When VIRTIO_IOMMU_F_BYPASS_CONFIG is not supported by the device, we
currently fail attaching to an identity domain. Future patches will
instead create identity mappings in this case.

Reviewed-by: default avatarKevin Tian <kevin.tian@intel.com>
Signed-off-by: default avatarJean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: default avatarEric Auger <eric.auger@redhat.com>
Link: https://lore.kernel.org/r/20211201173323.1045819-3-jean-philippe@linaro.org


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 063ebb19

drivers/iommu/virtio-iommu.c

+19 −1
Original line number Diff line number Diff line
@@ -71,6 +71,7 @@ struct viommu_domain { 
	struct rb_root_cached		mappings;



	unsigned long			nr_endpoints;

	bool				bypass;

};



struct viommu_endpoint {
@@ -587,7 +588,9 @@ static struct iommu_domain *viommu_domain_alloc(unsigned type) 
{

	struct viommu_domain *vdomain;



	if (type != IOMMU_DOMAIN_UNMANAGED && type != IOMMU_DOMAIN_DMA)

	if (type != IOMMU_DOMAIN_UNMANAGED &&

	    type != IOMMU_DOMAIN_DMA &&

	    type != IOMMU_DOMAIN_IDENTITY)

		return NULL;



	vdomain = kzalloc(sizeof(*vdomain), GFP_KERNEL);
@@ -630,6 +633,17 @@ static int viommu_domain_finalise(struct viommu_endpoint *vdev, 
	vdomain->map_flags	= viommu->map_flags;

	vdomain->viommu		= viommu;



	if (domain->type == IOMMU_DOMAIN_IDENTITY) {

		if (!virtio_has_feature(viommu->vdev,

					VIRTIO_IOMMU_F_BYPASS_CONFIG)) {

			ida_free(&viommu->domain_ids, vdomain->id);

			vdomain->viommu = NULL;

			return -EOPNOTSUPP;

		}



		vdomain->bypass = true;

	}



	return 0;

}
@@ -691,6 +705,9 @@ static int viommu_attach_dev(struct iommu_domain *domain, struct device *dev) 
		.domain		= cpu_to_le32(vdomain->id),

	};



	if (vdomain->bypass)

		req.flags |= cpu_to_le32(VIRTIO_IOMMU_ATTACH_F_BYPASS);



	for (i = 0; i < fwspec->num_ids; i++) {

		req.endpoint = cpu_to_le32(fwspec->ids[i]);
@@ -1132,6 +1149,7 @@ static unsigned int features[] = { 
	VIRTIO_IOMMU_F_DOMAIN_RANGE,

	VIRTIO_IOMMU_F_PROBE,

	VIRTIO_IOMMU_F_MMIO,

	VIRTIO_IOMMU_F_BYPASS_CONFIG,

};



static struct virtio_device_id id_table[] = {