iommu/vt-d: Update IOMMU state when memory hotplug happens

If static identity domain is created, IOMMU driver needs to update
si_domain page table when memory hotplug event happens. Otherwise
PCI device DMA operations can't access the hot-added memory regions.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Joerg Roedel <joro@8bytes.org>

2 files changed, 128 insertions, 7 deletions

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index dd576c067d0d..484d669d2720 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -33,6 +33,7 @@
 #include <linux/dmar.h>
 #include <linux/dma-mapping.h>
 #include <linux/mempool.h>
+#include <linux/memory.h>
 #include <linux/timer.h>
 #include <linux/iova.h>
 #include <linux/iommu.h>
@@ -3683,6 +3684,73 @@ static struct notifier_block device_nb = {
         .notifier_call = device_notifier,
 };
 
+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;
+
+        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("dmar: failed to build identity map for [%llx-%llx]\n",
+                                start, end);
+                        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;
+
+                        iova = find_iova(&si_domain->iovad, start_vpfn);
+                        if (iova == NULL) {
+                                pr_debug("dmar: 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("dmar: failed to split IOVA PFN [%lx-%lx]\n",
+                                        start_vpfn, last_vpfn);
+                                return NOTIFY_BAD;
+                        }
+
+                        rcu_read_lock();
+                        for_each_active_iommu(iommu, drhd)
+                                iommu_flush_iotlb_psi(iommu, si_domain->id,
+                                        iova->pfn_lo,
+                                        iova->pfn_hi - iova->pfn_lo + 1, 0);
+                        rcu_read_unlock();
+                        dma_pte_clear_range(si_domain, iova->pfn_lo,
+                                            iova->pfn_hi);
+                        dma_pte_free_pagetable(si_domain, iova->pfn_lo,
+                                               iova->pfn_hi);
+
+                        start_vpfn = iova->pfn_hi + 1;
+                        free_iova_mem(iova);
+                }
+                break;
+        }
+
+        return NOTIFY_OK;
+}
+
+static struct notifier_block intel_iommu_memory_nb = {
+        .notifier_call = intel_iommu_memory_notifier,
+        .priority = 0
+};
+
 int __init intel_iommu_init(void)
 {
         int ret = -ENODEV;
@@ -3755,8 +3823,9 @@ int __init intel_iommu_init(void)
         init_iommu_pm_ops();
 
         bus_set_iommu(&pci_bus_type, &intel_iommu_ops);
-
         bus_register_notifier(&pci_bus_type, &device_nb);
+        if (si_domain && !hw_pass_through)
+                register_memory_notifier(&intel_iommu_memory_nb);
 
         intel_iommu_enabled = 1;
 
diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index 67da6cff74e8..f6b17e6af2fb 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -342,19 +342,30 @@ __is_range_overlap(struct rb_node *node,
         return 0;
 }
 
+static inline struct iova *
+alloc_and_init_iova(unsigned long pfn_lo, unsigned long pfn_hi)
+{
+        struct iova *iova;
+
+        iova = alloc_iova_mem();
+        if (iova) {
+                iova->pfn_lo = pfn_lo;
+                iova->pfn_hi = pfn_hi;
+        }
+
+        return iova;
+}
+
 static struct iova *
 __insert_new_range(struct iova_domain *iovad,
         unsigned long pfn_lo, unsigned long pfn_hi)
 {
         struct iova *iova;
 
-        iova = alloc_iova_mem();
-        if (!iova)
-                return iova;
+        iova = alloc_and_init_iova(pfn_lo, pfn_hi);
+        if (iova)
+                iova_insert_rbtree(&iovad->rbroot, iova);
 
-        iova->pfn_hi = pfn_hi;
-        iova->pfn_lo = pfn_lo;
-        iova_insert_rbtree(&iovad->rbroot, iova);
         return iova;
 }
 
@@ -433,3 +444,44 @@ copy_reserved_iova(struct iova_domain *from, struct iova_domain *to)
         }
         spin_unlock_irqrestore(&from->iova_rbtree_lock, flags);
 }
+
+struct iova *
+split_and_remove_iova(struct iova_domain *iovad, struct iova *iova,
+                      unsigned long pfn_lo, unsigned long pfn_hi)
+{
+        unsigned long flags;
+        struct iova *prev = NULL, *next = NULL;
+
+        spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
+        if (iova->pfn_lo < pfn_lo) {
+                prev = alloc_and_init_iova(iova->pfn_lo, pfn_lo - 1);
+                if (prev == NULL)
+                        goto error;
+        }
+        if (iova->pfn_hi > pfn_hi) {
+                next = alloc_and_init_iova(pfn_hi + 1, iova->pfn_hi);
+                if (next == NULL)
+                        goto error;
+        }
+
+        __cached_rbnode_delete_update(iovad, iova);
+        rb_erase(&iova->node, &iovad->rbroot);
+
+        if (prev) {
+                iova_insert_rbtree(&iovad->rbroot, prev);
+                iova->pfn_lo = pfn_lo;
+        }
+        if (next) {
+                iova_insert_rbtree(&iovad->rbroot, next);
+                iova->pfn_hi = pfn_hi;
+        }
+        spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
+
+        return iova;
+
+error:
+        spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
+        if (prev)
+                free_iova_mem(prev);
+        return NULL;
+}