Re: [PATCH v3 3/5] iommu/uapi: Use named union for user data

Lu Baolu
2020-06-24T06:30:08Z

Hi Jacob,

On 2020/6/24 1:03, Jacob Pan wrote:
> IOMMU UAPI data size is filled by the user space which must be validated
> by ther kernel. To ensure backward compatibility, user data can only be
> extended by either re-purpose padding bytes or extend the variable sized
> union at the end. No size change is allowed before the union. Therefore,
> the minimum size is the offset of the union.
>
> To use offsetof() on the union, we must make it named.
>
> Link: https://lkml.org/lkml/2020/6/11/834
> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> ---
> drivers/iommu/intel/iommu.c | 24 ++++++++++++------------
> drivers/iommu/intel/svm.c | 2 +-
> include/uapi/linux/iommu.h | 4 ++--
> 3 files changed, 15 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 50fc62413a35..59cba214ef13 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -5409,8 +5409,8 @@ intel_iommu_sva_invalidate(struct iommu_domain *domain, struct device *dev,
>
> /* Size is only valid in address selective invalidation */
> if (inv_info->granularity == IOMMU_INV_GRANU_ADDR)
> - size = to_vtd_size(inv_info->addr_info.granule_size,
> - inv_info->addr_info.nb_granules);
> + size = to_vtd_size(inv_info->granu.addr_info.granule_size,
> + inv_info->granu.addr_info.nb_granules);
>
> for_each_set_bit(cache_type,
> (unsigned long *)&inv_info->cache,
> @@ -5431,20 +5431,20 @@ intel_iommu_sva_invalidate(struct iommu_domain *domain, struct device *dev,
> * granularity.
> */
> if (inv_info->granularity == IOMMU_INV_GRANU_PASID &&
> - (inv_info->pasid_info.flags & IOMMU_INV_PASID_FLAGS_PASID))
> - pasid = inv_info->pasid_info.pasid;
> + (inv_info->granu.pasid_info.flags & IOMMU_INV_PASID_FLAGS_PASID))
> + pasid = inv_info->granu.pasid_info.pasid;
> else if (inv_info->granularity == IOMMU_INV_GRANU_ADDR &&
> - (inv_info->addr_info.flags & IOMMU_INV_ADDR_FLAGS_PASID))
> - pasid = inv_info->addr_info.pasid;
> + (inv_info->granu.addr_info.flags & IOMMU_INV_ADDR_FLAGS_PASID))
> + pasid = inv_info->granu.addr_info.pasid;
>
> switch (BIT(cache_type)) {
> case IOMMU_CACHE_INV_TYPE_IOTLB:
> /* HW will ignore LSB bits based on address mask */
> if (inv_info->granularity == IOMMU_INV_GRANU_ADDR &&
> size &&
> - (inv_info->addr_info.addr & ((BIT(VTD_PAGE_SHIFT + size)) - 1))) {
> + (inv_info->granu.addr_info.addr & ((BIT(VTD_PAGE_SHIFT + size)) - 1))) {

Nit: Keep it aligned. With this tweaked,

Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>

Best regards,
baolu

> WARN_ONCE(1, "Address out of range, 0x%llx, size order %llu\n",
> - inv_info->addr_info.addr, size);
> + inv_info->granu.addr_info.addr, size);
> }
>
> /*
> @@ -5452,9 +5452,9 @@ intel_iommu_sva_invalidate(struct iommu_domain *domain, struct device *dev,
> * We use npages = -1 to indicate that.
> */
> qi_flush_piotlb(iommu, did, pasid,
> - mm_to_dma_pfn(inv_info->addr_info.addr),
> + mm_to_dma_pfn(inv_info->granu.addr_info.addr),
> (granu == QI_GRAN_NONG_PASID) ? -1 : 1 << size,
> - inv_info->addr_info.flags & IOMMU_INV_ADDR_FLAGS_LEAF);
> + inv_info->granu.addr_info.flags & IOMMU_INV_ADDR_FLAGS_LEAF);
>
> if (!info->ats_enabled)
> break;
> @@ -5475,13 +5475,13 @@ intel_iommu_sva_invalidate(struct iommu_domain *domain, struct device *dev,
> size = 64 - VTD_PAGE_SHIFT;
> addr = 0;
> } else if (inv_info->granularity == IOMMU_INV_GRANU_ADDR)
> - addr = inv_info->addr_info.addr;
> + addr = inv_info->granu.addr_info.addr;
>
> if (info->ats_enabled)
> qi_flush_dev_iotlb_pasid(iommu, sid,
> info->pfsid, pasid,
> info->ats_qdep,
> - inv_info->addr_info.addr,
> + inv_info->granu.addr_info.addr,
> size);
> else
> pr_warn_ratelimited("Passdown device IOTLB flush w/o ATS!\n");
> diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
> index d386853121a2..713b3a218483 100644
> --- a/drivers/iommu/intel/svm.c
> +++ b/drivers/iommu/intel/svm.c
> @@ -338,7 +338,7 @@ int intel_svm_bind_gpasid(struct iommu_domain *domain, struct device *dev,
> spin_lock(&iommu->lock);
> ret = intel_pasid_setup_nested(iommu, dev,
> (pgd_t *)(uintptr_t)data->gpgd,
> - data->hpasid, &data->vtd, dmar_domain,
> + data->hpasid, &data->vendor.vtd, dmar_domain,
> data->addr_width);
> spin_unlock(&iommu->lock);
> if (ret) {
> diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h
> index 303f148a5cd7..1afc6610b0ad 100644
> --- a/include/uapi/linux/iommu.h
> +++ b/include/uapi/linux/iommu.h
> @@ -263,7 +263,7 @@ struct iommu_cache_invalidate_info {
> union {
> struct iommu_inv_pasid_info pasid_info;
> struct iommu_inv_addr_info addr_info;
> - };
> + } granu;
> };
>
> /**
> @@ -329,7 +329,7 @@ struct iommu_gpasid_bind_data {
> /* Vendor specific data */
> union {
> struct iommu_gpasid_bind_data_vtd vtd;
> - };
> + } vendor;
> };
>
> #endif /* _UAPI_IOMMU_H */