Hi Eric,
> From: Auger Eric <eric.auger@xxxxxxxxxx>
>
> Hi Yi,
>
> Please add a commit message: instead of returning a boolean for
> DOMAIN_ATTR_NESTING, arm_smmu_domain_get_attr() returns a
> iommu_nesting_info handle.
will do. thanks for the suggestion.
>
> On 7/4/20 1:26 PM, Liu Yi L wrote:
> > Cc: Will Deacon <will@xxxxxxxxxx>
> > Cc: Robin Murphy <robin.murphy@xxxxxxx>
> > Cc: Eric Auger <eric.auger@xxxxxxxxxx>
> > Cc: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>
> > Suggested-by: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>
> > Signed-off-by: Liu Yi L <yi.l.liu@xxxxxxxxx>
> > Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> > ---
> > drivers/iommu/arm-smmu-v3.c | 29 +++++++++++++++++++++++++++--
> > drivers/iommu/arm-smmu.c | 29 +++++++++++++++++++++++++++--
> > 2 files changed, 54 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> > index f578677..0c45d4d 100644
> > --- a/drivers/iommu/arm-smmu-v3.c
> > +++ b/drivers/iommu/arm-smmu-v3.c
> > @@ -3019,6 +3019,32 @@ static struct iommu_group
> *arm_smmu_device_group(struct device *dev)
> > return group;
> > }
> >
> > +static int arm_smmu_domain_nesting_info(struct arm_smmu_domain
> *smmu_domain,
> > + void *data)
> > +{
> > + struct iommu_nesting_info *info = (struct iommu_nesting_info *) data;
> > + u32 size;
> > +
> > + if (!info || smmu_domain->stage != ARM_SMMU_DOMAIN_NESTED)
> > + return -ENODEV;
> > +
> > + size = sizeof(struct iommu_nesting_info);
> > +
> > + /*
> > + * if provided buffer size is not equal to the size, should
> > + * return 0 and also the expected buffer size to caller.
> > + */
> > + if (info->size != size) {
> < size?
< size may work as well. but I'd like the caller provide exact buffer size. not sure
if it is demand in kernel. do you have any suggestion?
> > + info->size = size;
> > + return 0;
> > + }
> > +
> > + /* report an empty iommu_nesting_info for now */
> > + memset(info, 0x0, size);
> > + info->size = size;
> For info, the current SMMU NESTED mode is not enabling any nesting. It just forces
> the usage of the 2st stage instead of stage1 for single stage translation.
yep. The intention is as below:
" However it requires changing the get_attr(NESTING) implementations in both
SMMU drivers as a precursor of this series, to avoid breaking
VFIO_TYPE1_NESTING_IOMMU on Arm. Since we haven't yet defined the
nesting_info structs for SMMUv2 and v3, I suppose we could return an empty
struct iommu_nesting_info for now?"
https://lore.kernel.org/linux-iommu/20200617143909.GA886590@myrica/
do you think any other needs to be done for now?
Regards,
Yi Liu
> Thanks
>
> Eric
> > + return 0;
> > +}
> > +
> > static int arm_smmu_domain_get_attr(struct iommu_domain *domain,
> > enum iommu_attr attr, void *data) { @@ -
> 3028,8 +3054,7 @@
> > static int arm_smmu_domain_get_attr(struct iommu_domain *domain,
> > case IOMMU_DOMAIN_UNMANAGED:
> > switch (attr) {
> > case DOMAIN_ATTR_NESTING:
> > - *(int *)data = (smmu_domain->stage ==
> ARM_SMMU_DOMAIN_NESTED);
> > - return 0;
> > + return arm_smmu_domain_nesting_info(smmu_domain,
> data);
> > default:
> > return -ENODEV;
> > }
> > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index
> > 243bc4c..908607d 100644
> > --- a/drivers/iommu/arm-smmu.c
> > +++ b/drivers/iommu/arm-smmu.c
> > @@ -1506,6 +1506,32 @@ static struct iommu_group
> *arm_smmu_device_group(struct device *dev)
> > return group;
> > }
> >
> > +static int arm_smmu_domain_nesting_info(struct arm_smmu_domain
> *smmu_domain,
> > + void *data)
> > +{
> > + struct iommu_nesting_info *info = (struct iommu_nesting_info *) data;
> > + u32 size;
> > +
> > + if (!info || smmu_domain->stage != ARM_SMMU_DOMAIN_NESTED)
> > + return -ENODEV;
> > +
> > + size = sizeof(struct iommu_nesting_info);
> > +
> > + /*
> > + * if provided buffer size is not equal to the size, should
> > + * return 0 and also the expected buffer size to caller.
> > + */
> > + if (info->size != size) {
> > + info->size = size;
> > + return 0;
> > + }
> > +
> > + /* report an empty iommu_nesting_info for now */
> > + memset(info, 0x0, size);
> > + info->size = size;
> > + return 0;
> > +}
> > +
> > static int arm_smmu_domain_get_attr(struct iommu_domain *domain,
> > enum iommu_attr attr, void *data) { @@ -
> 1515,8 +1541,7 @@
> > static int arm_smmu_domain_get_attr(struct iommu_domain *domain,
> > case IOMMU_DOMAIN_UNMANAGED:
> > switch (attr) {
> > case DOMAIN_ATTR_NESTING:
> > - *(int *)data = (smmu_domain->stage ==
> ARM_SMMU_DOMAIN_NESTED);
> > - return 0;
> > + return arm_smmu_domain_nesting_info(smmu_domain,
> data);
> > default:
> > return -ENODEV;
> > }
> >
