Jean-Philippe Brucker
2021-Nov-23 15:52 UTC
[PATCH v2 2/5] 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: Kevin Tian <kevin.tian at intel.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe at linaro.org>
---
drivers/iommu/virtio-iommu.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index 80930ce04a16..ee8a7afd667b 100644
--- a/drivers/iommu/virtio-iommu.c
+++ b/drivers/iommu/virtio-iommu.c
@@ -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 = 0;
+ 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[] = {
--
2.33.1
Hi Jean, On 11/23/21 4:52 PM, Jean-Philippe Brucker wrote:> 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: Kevin Tian <kevin.tian at intel.com> > Signed-off-by: Jean-Philippe Brucker <jean-philippe at linaro.org> > --- > drivers/iommu/virtio-iommu.c | 20 +++++++++++++++++++- > 1 file changed, 19 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c > index 80930ce04a16..ee8a7afd667b 100644 > --- a/drivers/iommu/virtio-iommu.c > +++ b/drivers/iommu/virtio-iommu.c > @@ -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,nit: couldn't the check be done before the ida_alloc_range(), simplifying the failure cleanup? Thanks Eric> + VIRTIO_IOMMU_F_BYPASS_CONFIG)) { > + ida_free(&viommu->domain_ids, vdomain->id); > + vdomain->viommu = 0; > + 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[] = {