RE: [PATCH 9/9] iommu/vt-d: Clean up PASID talbe management for SVM

From: Liu, Yi L
Date: Tue May 01 2018 - 05:24:34 EST


> From: Lu Baolu [mailto:baolu.lu@xxxxxxxxxxxxxxx]
> Sent: Tuesday, April 17, 2018 11:03 AM
>
> The previous per iommu pasid table alloc/free interfaces
> are no longer used. Clean up the driver by removing it.

I think this patch major cleans intel_svm_alloc_pasid_tables
and intel_svm_free_pasid_tables. Actually, only PASID State
table allocation is remained in these two functions.

Since PASID Table is modified to be per-iommu domain. How
about the PASID State Table? Should it also be per-iommu domain?

Thanks,
Yi Liu
> Cc: Ashok Raj <ashok.raj@xxxxxxxxx>
> Cc: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
> Cc: Liu Yi L <yi.l.liu@xxxxxxxxx>
> Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> ---
> drivers/iommu/intel-iommu.c | 6 +++---
> drivers/iommu/intel-svm.c | 17 ++---------------
> include/linux/intel-iommu.h | 5 ++---
> 3 files changed, 7 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index 5fe7f91..5acb90d 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -1736,7 +1736,7 @@ static void free_dmar_iommu(struct intel_iommu *iommu)
> if (pasid_enabled(iommu)) {
> if (ecap_prs(iommu->ecap))
> intel_svm_finish_prq(iommu);
> - intel_svm_free_pasid_tables(iommu);
> + intel_svm_exit(iommu);
> }
> #endif
> }
> @@ -3291,7 +3291,7 @@ static int __init init_dmars(void)
> hw_pass_through = 0;
> #ifdef CONFIG_INTEL_IOMMU_SVM
> if (pasid_enabled(iommu))
> - intel_svm_alloc_pasid_tables(iommu);
> + intel_svm_init(iommu);
> #endif
> }
>
> @@ -4268,7 +4268,7 @@ static int intel_iommu_add(struct dmar_drhd_unit *dmaru)
>
> #ifdef CONFIG_INTEL_IOMMU_SVM
> if (pasid_enabled(iommu))
> - intel_svm_alloc_pasid_tables(iommu);
> + intel_svm_init(iommu);
> #endif
>
> if (dmaru->ignored) {
> diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
> index 3b14819..38cae65 100644
> --- a/drivers/iommu/intel-svm.c
> +++ b/drivers/iommu/intel-svm.c
> @@ -34,7 +34,7 @@
>
> static irqreturn_t prq_event_thread(int irq, void *d);
>
> -int intel_svm_alloc_pasid_tables(struct intel_iommu *iommu)
> +int intel_svm_init(struct intel_iommu *iommu)
> {
> struct page *pages;
> int order;
> @@ -59,15 +59,6 @@ int intel_svm_alloc_pasid_tables(struct intel_iommu *iommu)
> iommu->pasid_max = 0x20000;
>
> order = get_order(sizeof(struct pasid_entry) * iommu->pasid_max);
> - pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
> - if (!pages) {
> - pr_warn("IOMMU: %s: Failed to allocate PASID table\n",
> - iommu->name);
> - return -ENOMEM;
> - }
> - iommu->pasid_table = page_address(pages);
> - pr_info("%s: Allocated order %d PASID table.\n", iommu->name, order);
> -
> if (ecap_dis(iommu->ecap)) {
> /* Just making it explicit... */
> BUILD_BUG_ON(sizeof(struct pasid_entry) != sizeof(struct
> pasid_state_entry));
> @@ -82,14 +73,10 @@ int intel_svm_alloc_pasid_tables(struct intel_iommu
> *iommu)
> return 0;
> }
>
> -int intel_svm_free_pasid_tables(struct intel_iommu *iommu)
> +int intel_svm_exit(struct intel_iommu *iommu)
> {
> int order = get_order(sizeof(struct pasid_entry) * iommu->pasid_max);
>
> - if (iommu->pasid_table) {
> - free_pages((unsigned long)iommu->pasid_table, order);
> - iommu->pasid_table = NULL;
> - }
> if (iommu->pasid_state_table) {
> free_pages((unsigned long)iommu->pasid_state_table, order);
> iommu->pasid_state_table = NULL;
> diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
> index 08e5811..44c7613 100644
> --- a/include/linux/intel-iommu.h
> +++ b/include/linux/intel-iommu.h
> @@ -470,7 +470,6 @@ struct intel_iommu {
> * devices away to userspace processes (e.g. for DPDK) and don't
> * want to trust that userspace will use *only* the PASID it was
> * told to. But while it's all driver-arbitrated, we're fine. */
> - struct pasid_entry *pasid_table;
> struct pasid_state_entry *pasid_state_table;
> struct page_req_dsc *prq;
> unsigned char prq_name[16]; /* Name for PRQ interrupt */
> @@ -539,8 +538,8 @@ void free_pgtable_page(void *vaddr);
> struct intel_iommu *domain_get_iommu(struct dmar_domain *domain);
>
> #ifdef CONFIG_INTEL_IOMMU_SVM
> -extern int intel_svm_alloc_pasid_tables(struct intel_iommu *iommu);
> -extern int intel_svm_free_pasid_tables(struct intel_iommu *iommu);
> +int intel_svm_init(struct intel_iommu *iommu);
> +int intel_svm_exit(struct intel_iommu *iommu);
> extern int intel_svm_enable_prq(struct intel_iommu *iommu);
> extern int intel_svm_finish_prq(struct intel_iommu *iommu);
>
> --
> 2.7.4