Re: [PATCH 3/8] iommu/vt-d: Remove IOVA handling code from non-dma_ops path

[Tom Murphy <murphyt7@tcd.ie>]

Could we merge patch 1-3 from this series? it just cleans up weird
code and merging these patches will cover some of the work needed to
move the intel iommu driver to the dma-iommu api in the future.

On Sat, 21 Dec 2019 at 07:04, Tom Murphy <murphyt7@tcd.ie> wrote:
>
> Remove all IOVA handling code from the non-dma_ops path in the intel
> iommu driver.
>
> There's no need for the non-dma_ops path to keep track of IOVAs. The
> whole point of the non-dma_ops path is that it allows the IOVAs to be
> handled separately. The IOVA handling code removed in this patch is
> pointless.
>
> Signed-off-by: Tom Murphy <murphyt7@tcd.ie>
> ---
>  drivers/iommu/intel-iommu.c | 89 ++++++++++++++-----------------------
>  1 file changed, 33 insertions(+), 56 deletions(-)
>
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index 64b1a9793daa..8d72ea0fb843 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -1908,7 +1908,8 @@ static void domain_exit(struct dmar_domain *domain)
>         domain_remove_dev_info(domain);
>
>         /* destroy iovas */
> -       put_iova_domain(&domain->iovad);
> +       if (domain->domain.type == IOMMU_DOMAIN_DMA)
> +               put_iova_domain(&domain->iovad);
>
>         if (domain->pgd) {
>                 struct page *freelist;
> @@ -2671,19 +2672,9 @@ static struct dmar_domain *set_domain_for_dev(struct device *dev,
>  }
>
>  static int iommu_domain_identity_map(struct dmar_domain *domain,
> -                                    unsigned long long start,
> -                                    unsigned long long end)
> +                                    unsigned long first_vpfn,
> +                                    unsigned long last_vpfn)
>  {
> -       unsigned long first_vpfn = start >> VTD_PAGE_SHIFT;
> -       unsigned long last_vpfn = end >> VTD_PAGE_SHIFT;
> -
> -       if (!reserve_iova(&domain->iovad, dma_to_mm_pfn(first_vpfn),
> -                         dma_to_mm_pfn(last_vpfn))) {
> -               pr_err("Reserving iova failed\n");
> -               return -ENOMEM;
> -       }
> -
> -       pr_debug("Mapping reserved region %llx-%llx\n", start, end);
>         /*
>          * RMRR range might have overlap with physical memory range,
>          * clear it first
> @@ -2760,7 +2751,8 @@ static int __init si_domain_init(int hw)
>
>                 for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
>                         ret = iommu_domain_identity_map(si_domain,
> -                                       PFN_PHYS(start_pfn), PFN_PHYS(end_pfn));
> +                                       mm_to_dma_pfn(start_pfn),
> +                                       mm_to_dma_pfn(end_pfn));
>                         if (ret)
>                                 return ret;
>                 }
> @@ -4593,58 +4585,37 @@ static int intel_iommu_memory_notifier(struct notifier_block *nb,
>                                        unsigned long val, void *v)
>  {
>         struct memory_notify *mhp = v;
> -       unsigned long long start, end;
> -       unsigned long start_vpfn, last_vpfn;
> +       unsigned long start_vpfn = mm_to_dma_pfn(mhp->start_pfn);
> +       unsigned long last_vpfn = mm_to_dma_pfn(mhp->start_pfn +
> +                       mhp->nr_pages - 1);
>
>         switch (val) {
>         case MEM_GOING_ONLINE:
> -               start = mhp->start_pfn << PAGE_SHIFT;
> -               end = ((mhp->start_pfn + mhp->nr_pages) << PAGE_SHIFT) - 1;
> -               if (iommu_domain_identity_map(si_domain, start, end)) {
> -                       pr_warn("Failed to build identity map for [%llx-%llx]\n",
> -                               start, end);
> +               if (iommu_domain_identity_map(si_domain, start_vpfn,
> +                                       last_vpfn)) {
> +                       pr_warn("Failed to build identity map for [%lx-%lx]\n",
> +                               start_vpfn, last_vpfn);
>                         return NOTIFY_BAD;
>                 }
>                 break;
>
>         case MEM_OFFLINE:
>         case MEM_CANCEL_ONLINE:
> -               start_vpfn = mm_to_dma_pfn(mhp->start_pfn);
> -               last_vpfn = mm_to_dma_pfn(mhp->start_pfn + mhp->nr_pages - 1);
> -               while (start_vpfn <= last_vpfn) {
> -                       struct iova *iova;
> +               {
>                         struct dmar_drhd_unit *drhd;
>                         struct intel_iommu *iommu;
>                         struct page *freelist;
>
> -                       iova = find_iova(&si_domain->iovad, start_vpfn);
> -                       if (iova == NULL) {
> -                               pr_debug("Failed get IOVA for PFN %lx\n",
> -                                        start_vpfn);
> -                               break;
> -                       }
> -
> -                       iova = split_and_remove_iova(&si_domain->iovad, iova,
> -                                                    start_vpfn, last_vpfn);
> -                       if (iova == NULL) {
> -                               pr_warn("Failed to split IOVA PFN [%lx-%lx]\n",
> -                                       start_vpfn, last_vpfn);
> -                               return NOTIFY_BAD;
> -                       }
> -
> -                       freelist = domain_unmap(si_domain, iova->pfn_lo,
> -                                              iova->pfn_hi);
> +                       freelist = domain_unmap(si_domain, start_vpfn,
> +                                       last_vpfn);
>
>                         rcu_read_lock();
>                         for_each_active_iommu(iommu, drhd)
>                                 iommu_flush_iotlb_psi(iommu, si_domain,
> -                                       iova->pfn_lo, iova_size(iova),
> +                                       start_vpfn, mhp->nr_pages,
>                                         !freelist, 0);
>                         rcu_read_unlock();
>                         dma_free_pagelist(freelist);
> -
> -                       start_vpfn = iova->pfn_hi + 1;
> -                       free_iova_mem(iova);
>                 }
>                 break;
>         }
> @@ -4672,8 +4643,9 @@ static void free_all_cpu_cached_iovas(unsigned int cpu)
>                 for (did = 0; did < cap_ndoms(iommu->cap); did++) {
>                         domain = get_iommu_domain(iommu, (u16)did);
>
> -                       if (!domain)
> +                       if (!domain || domain->domain.type != IOMMU_DOMAIN_DMA)
>                                 continue;
> +
>                         free_cpu_cached_iovas(cpu, &domain->iovad);
>                 }
>         }
> @@ -5095,9 +5067,6 @@ static int md_domain_init(struct dmar_domain *domain, int guest_width)
>  {
>         int adjust_width;
>
> -       init_iova_domain(&domain->iovad, VTD_PAGE_SIZE, IOVA_START_PFN);
> -       domain_reserve_special_ranges(domain);
> -
>         /* calculate AGAW */
>         domain->gaw = guest_width;
>         adjust_width = guestwidth_to_adjustwidth(guest_width);
> @@ -5116,6 +5085,18 @@ static int md_domain_init(struct dmar_domain *domain, int guest_width)
>         return 0;
>  }
>
> +static void intel_init_iova_domain(struct dmar_domain *dmar_domain)
> +{
> +       init_iova_domain(&dmar_domain->iovad, VTD_PAGE_SIZE, IOVA_START_PFN);
> +       copy_reserved_iova(&reserved_iova_list, &dmar_domain->iovad);
> +
> +       if (init_iova_flush_queue(&dmar_domain->iovad, iommu_flush_iova,
> +                               iova_entry_free)) {
> +               pr_warn("iova flush queue initialization failed\n");
> +               intel_iommu_strict = 1;
> +       }
> +}
> +
>  static struct iommu_domain *intel_iommu_domain_alloc(unsigned type)
>  {
>         struct dmar_domain *dmar_domain;
> @@ -5136,12 +5117,8 @@ static struct iommu_domain *intel_iommu_domain_alloc(unsigned type)
>                         return NULL;
>                 }
>
> -               if (type == IOMMU_DOMAIN_DMA &&
> -                   init_iova_flush_queue(&dmar_domain->iovad,
> -                                         iommu_flush_iova, iova_entry_free)) {
> -                       pr_warn("iova flush queue initialization failed\n");
> -                       intel_iommu_strict = 1;
> -               }
> +               if (type == IOMMU_DOMAIN_DMA)
> +                       intel_init_iova_domain(dmar_domain);
>
>                 domain_update_iommu_cap(dmar_domain);
>
> --
> 2.20.1
>
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