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

Tom Murphy
2020-03-20T06:31:03Z

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
>