Re: [PATCH RFC 04/11] iommu/vt-d: Add SVA domain support

Jason Gunthorpe
2022-03-21T11:57:26Z

On Sun, Mar 20, 2022 at 02:40:23PM +0800, Lu Baolu wrote:
> Add support for SVA domain allocation and provide an SVA-specific
> iommu_domain_ops.
>
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> include/linux/intel-iommu.h | 1 +
> drivers/iommu/intel/iommu.c | 12 ++++++++++++
> drivers/iommu/intel/svm.c | 34 ++++++++++++++++++++++++++++++++++
> 3 files changed, 47 insertions(+)
>
> diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
> index 2f9891cb3d00..c14283137fb5 100644
> +++ b/include/linux/intel-iommu.h
> @@ -744,6 +744,7 @@ void intel_svm_unbind(struct iommu_sva *handle);
> u32 intel_svm_get_pasid(struct iommu_sva *handle);
> int intel_svm_page_response(struct device *dev, struct iommu_fault_event *evt,
> struct iommu_page_response *msg);
> +extern const struct iommu_domain_ops intel_svm_domain_ops;
>
> struct intel_svm_dev {
> struct list_head list;
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index c1b91bce1530..d55dca3eacf8 100644
> +++ b/drivers/iommu/intel/iommu.c
> @@ -4318,6 +4318,18 @@ static struct iommu_domain *intel_iommu_domain_alloc(unsigned type)
> return domain;
> case IOMMU_DOMAIN_IDENTITY:
> return &si_domain->domain;
> +#ifdef CONFIG_INTEL_IOMMU_SVM
> + case IOMMU_DOMAIN_SVA:
> + dmar_domain = alloc_domain(type);
> + if (!dmar_domain) {
> + pr_err("Can't allocate sva domain\n");

Don't put random pr_err's/etc in drivers. At least try to use dev_err

> + return NULL;
> + }
> + domain = &dmar_domain->domain;
> + domain->ops = &intel_svm_domain_ops;
> +
> + return domain;
> +#endif /* CONFIG_INTEL_IOMMU_SVM */
> default:
> return NULL;
> }
> diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
> index ee5ecde5b318..b9f4dd7057d1 100644
> +++ b/drivers/iommu/intel/svm.c
> @@ -932,3 +932,37 @@ int intel_svm_page_response(struct device *dev,
> mutex_unlock(&pasid_mutex);
> return ret;
> }
> +
> +static int intel_svm_attach_dev_pasid(struct iommu_domain *domain,
> + struct device *dev, ioasid_t pasid)
> +{
> + struct device_domain_info *info = dev_iommu_priv_get(dev);
> + struct mm_struct *mm = domain->sva_cookie;
> + struct intel_iommu *iommu = info->iommu;
> + struct iommu_sva *sva;
> +
> + mutex_lock(&pasid_mutex);
> + sva = intel_svm_bind_mm(iommu, dev, mm);
> + mutex_unlock(&pasid_mutex);
> +
> + return IS_ERR_OR_NULL(sva);

Never use IS_ERR_OR_NULL(), fix whatever is wrong in intel_svm_bind_mm()
that it can return NULL on failure.

> +const struct iommu_domain_ops intel_svm_domain_ops = {
> + .attach_dev_pasid = intel_svm_attach_dev_pasid,
> + .detach_dev_pasid = intel_svm_detach_dev_pasid,

Lets have consistent language either this is called SVA or SVM but not
both.

Jason