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Date: Fri, 17 Nov 2017 16:25:45 -0600
From: Tom Lendacky <thomas.lendacky@....com>
To: Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>,
linux-kernel@...r.kernel.org, iommu@...ts.linux-foundation.org
Cc: joro@...tes.org, jroedel@...e.de, alex.williamson@...hat.com
Subject: Re: [PATCH 2/2] iommu/amd: Add support for fast IOTLB flushing
On 11/17/2017 3:11 PM, Suravee Suthikulpanit wrote:
> From: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
>
> Implement the newly added IOTLB flushing interface by introducing
> per-protection-domain IOTLB flush list, which maintains a list of
> IOVAs to be invalidated (by INVALIDATE_IOTLB_PAGES command) during
> IOTLB sync.
>
> Cc: Joerg Roedel <jroedel@...e.de>
> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
> ---
> drivers/iommu/amd_iommu.c | 77 ++++++++++++++++++++++++++++++++++++++++-
> drivers/iommu/amd_iommu_init.c | 2 --
> drivers/iommu/amd_iommu_types.h | 2 ++
> 3 files changed, 78 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
> index 8e8874d..bf92809 100644
> --- a/drivers/iommu/amd_iommu.c
> +++ b/drivers/iommu/amd_iommu.c
> @@ -130,6 +130,12 @@ struct dma_ops_domain {
> static struct iova_domain reserved_iova_ranges;
> static struct lock_class_key reserved_rbtree_key;
>
> +struct iotlb_flush_entry {
> + struct list_head list;
> + unsigned long iova;
> + size_t size;
> +};
> +
> /****************************************************************************
> *
> * Helper functions
> @@ -2838,11 +2844,13 @@ static void protection_domain_free(struct protection_domain *domain)
> static int protection_domain_init(struct protection_domain *domain)
> {
> spin_lock_init(&domain->lock);
> + spin_lock_init(&domain->iotlb_flush_list_lock);
> mutex_init(&domain->api_lock);
> domain->id = domain_id_alloc();
> if (!domain->id)
> return -ENOMEM;
> INIT_LIST_HEAD(&domain->dev_list);
> + INIT_LIST_HEAD(&domain->iotlb_flush_list);
>
> return 0;
> }
> @@ -3047,7 +3055,6 @@ static size_t amd_iommu_unmap(struct iommu_domain *dom, unsigned long iova,
> unmap_size = iommu_unmap_page(domain, iova, page_size);
> mutex_unlock(&domain->api_lock);
>
> - domain_flush_tlb_pde(domain);
> domain_flush_complete(domain);
>
> return unmap_size;
> @@ -3167,6 +3174,71 @@ static bool amd_iommu_is_attach_deferred(struct iommu_domain *domain,
> return dev_data->defer_attach;
> }
>
> +static void amd_iommu_flush_iotlb_all(struct iommu_domain *domain)
> +{
> + struct protection_domain *dom = to_pdomain(domain);
> +
> + domain_flush_tlb_pde(dom);
> +}
> +
> +static void amd_iommu_iotlb_range_add(struct iommu_domain *domain,
> + unsigned long iova, size_t size)
> +{
> + struct protection_domain *pdom = to_pdomain(domain);
> + struct iotlb_flush_entry *entry, *p;
> + unsigned long flags;
> + bool found = false;
> +
> + spin_lock_irqsave(&pdom->iotlb_flush_list_lock, flags);
> + list_for_each_entry(p, &pdom->iotlb_flush_list, list) {
> + if (iova != p->iova)
> + continue;
> +
> + if (size > p->size) {
> + p->size = size;
> + pr_debug("%s: update range: iova=%#lx, size = %#lx\n",
> + __func__, p->iova, p->size);
> + }
> + found = true;
> + break;
> + }
> +
> + if (!found) {
> + entry = kzalloc(sizeof(struct iotlb_flush_entry),
> + GFP_ATOMIC);
> + if (!entry)
> + return;
You need to release the spinlock before returning here.
Thanks,
Tom
> +
> + pr_debug("%s: new range: iova=%lx, size=%#lx\n",
> + __func__, iova, size);
> +
> + entry->iova = iova;
> + entry->size = size;
> + list_add(&entry->list, &pdom->iotlb_flush_list);
> + }
> + spin_unlock_irqrestore(&pdom->iotlb_flush_list_lock, flags);
> +}
> +
> +static void amd_iommu_iotlb_sync(struct iommu_domain *domain)
> +{
> + struct protection_domain *pdom = to_pdomain(domain);
> + struct iotlb_flush_entry *entry, *next;
> + unsigned long flags;
> +
> + /* Note:
> + * Currently, IOMMU driver just flushes the whole IO/TLB for
> + * a given domain. So, just remove entries from the list here.
> + */
> + spin_lock_irqsave(&pdom->iotlb_flush_list_lock, flags);
> + list_for_each_entry_safe(entry, next, &pdom->iotlb_flush_list, list) {
> + list_del(&entry->list);
> + kfree(entry);
> + }
> + spin_unlock_irqrestore(&pdom->iotlb_flush_list_lock, flags);
> +
> + domain_flush_tlb_pde(pdom);
> +}
> +
> const struct iommu_ops amd_iommu_ops = {
> .capable = amd_iommu_capable,
> .domain_alloc = amd_iommu_domain_alloc,
> @@ -3185,6 +3257,9 @@ static bool amd_iommu_is_attach_deferred(struct iommu_domain *domain,
> .apply_resv_region = amd_iommu_apply_resv_region,
> .is_attach_deferred = amd_iommu_is_attach_deferred,
> .pgsize_bitmap = AMD_IOMMU_PGSIZES,
> + .flush_iotlb_all = amd_iommu_flush_iotlb_all,
> + .iotlb_range_add = amd_iommu_iotlb_range_add,
> + .iotlb_sync = amd_iommu_iotlb_sync,
> };
>
> /*****************************************************************************
> diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
> index 6fe2d03..1659377 100644
> --- a/drivers/iommu/amd_iommu_init.c
> +++ b/drivers/iommu/amd_iommu_init.c
> @@ -2489,8 +2489,6 @@ static int __init early_amd_iommu_init(void)
> */
> __set_bit(0, amd_iommu_pd_alloc_bitmap);
>
> - spin_lock_init(&amd_iommu_pd_lock);
> -
> /*
> * now the data structures are allocated and basically initialized
> * start the real acpi table scan
> diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
> index f6b24c7..30e1c68 100644
> --- a/drivers/iommu/amd_iommu_types.h
> +++ b/drivers/iommu/amd_iommu_types.h
> @@ -462,9 +462,11 @@ struct amd_iommu_fault {
> struct protection_domain {
> struct list_head list; /* for list of all protection domains */
> struct list_head dev_list; /* List of all devices in this domain */
> + struct list_head iotlb_flush_list; /* store iovas for iotlb sync */
> struct iommu_domain domain; /* generic domain handle used by
> iommu core code */
> spinlock_t lock; /* mostly used to lock the page table*/
> + spinlock_t iotlb_flush_list_lock; /* protect iova flush list */
> struct mutex api_lock; /* protect page tables in the iommu-api path */
> u16 id; /* the domain id written to the device table */
> int mode; /* paging mode (0-6 levels) */
>
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