From: Joerg Roedel <jroe...@suse.de>

Change the context table copy code to copy context
entrys one by one and check whether they are present and
mark the used domain-id as reserved in the allocation
bitmap. This way the domain-id will not be reused by new
domains allocated in the kdump kernel.

Tested-by: Baoquan He <b...@redhat.com>
Signed-off-by: Joerg Roedel <jroe...@suse.de>
---
 drivers/iommu/intel-iommu.c | 80 ++++++++++++++-------------------------------
 1 file changed, 25 insertions(+), 55 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 2602b33..82239e3 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -367,10 +367,6 @@ static inline int first_pte_in_page(struct dma_pte *pte)
  * do the same thing as crashdump kernel.
  */
 
-static struct context_entry *device_to_existing_context_entry(
-                               struct intel_iommu *iommu,
-                               u8 bus, u8 devfn);
-
 /*
  * A structure used to store the address allocated by ioremap();
  * The we need to call iounmap() to free them out of spin_lock_irqsave/unlock;
@@ -2337,7 +2333,6 @@ static struct dmar_domain *get_domain_for_dev(struct 
device *dev, int gaw)
        unsigned long flags;
        u8 bus, devfn;
        int did = -1;   /* Default to "no domain_id supplied" */
-       struct context_entry *ce = NULL;
 
        domain = find_domain(dev);
        if (domain)
@@ -2372,19 +2367,6 @@ static struct dmar_domain *get_domain_for_dev(struct 
device *dev, int gaw)
        if (!domain)
                return NULL;
 
-       if (iommu->pre_enabled_trans) {
-               /*
-                * if this device had a did in the old kernel
-                * use its values instead of generating new ones
-                */
-               ce = device_to_existing_context_entry(iommu, bus, devfn);
-
-               if (ce) {
-                       did = context_domain_id(ce);
-                       gaw = agaw_to_width(context_address_width(ce));
-               }
-       }
-
        domain->id = iommu_attach_domain_with_id(domain, iommu, did);
        if (domain->id < 0) {
                free_domain_mem(domain);
@@ -4931,49 +4913,37 @@ static void __init check_tylersburg_isoch(void)
               vtisochctrl);
 }
 
-static struct context_entry *device_to_existing_context_entry(
-                               struct intel_iommu *iommu,
-                               u8 bus, u8 devfn)
-{
-       struct root_entry *root;
-       struct context_entry *context;
-       struct context_entry *ret = NULL;
-       unsigned long flags;
-
-       spin_lock_irqsave(&iommu->lock, flags);
-       root = &iommu->root_entry[bus];
-       context = get_context_addr_from_root(root);
-       if (context && context_present(context+devfn))
-               ret = &context[devfn];
-       spin_unlock_irqrestore(&iommu->lock, flags);
-       return ret;
-}
-
 /*
- * Copy memory from a physically-addressed area into a virtually-addressed area
+ * Copy one context table
  */
-static int copy_from_oldmem_phys(void *to, phys_addr_t from, size_t size)
+static int copy_one_context_table(struct intel_iommu *iommu,
+                                 struct context_entry *ctxt_tbl,
+                                 phys_addr_t old_table_phys)
 {
-       void __iomem *virt_mem;
-       unsigned long offset;
-       unsigned long pfn;
+       struct context_entry __iomem *ctxt_tbl_old, ce;
+       int did, devfn;
 
-       pfn    = from >> VTD_PAGE_SHIFT;
-       offset = from & (~VTD_PAGE_MASK);
+       ctxt_tbl_old = ioremap_cache(old_table_phys, VTD_PAGE_SIZE);
+       if (!ctxt_tbl_old)
+               return -ENOMEM;
 
-       if (page_is_ram(pfn)) {
-               memcpy(to, pfn_to_kaddr(pfn) + offset, size);
-       } else {
-               virt_mem = ioremap_cache((unsigned long)from, size);
-               if (!virt_mem)
-                       return -ENOMEM;
+       for (devfn = 0; devfn < 256; devfn++) {
+               memcpy_fromio(&ce, &ctxt_tbl_old[devfn],
+                             sizeof(struct context_entry));
 
-               memcpy(to, virt_mem, size);
+               if (!context_present(&ce))
+                       continue;
+
+               did = context_domain_id(&ce);
+               if (did >=0 && did < cap_ndoms(iommu->cap))
+                       set_bit(did, iommu->domain_ids);
 
-               iounmap(virt_mem);
+               ctxt_tbl[devfn] = ce;
        }
 
-       return size;
+       iounmap(ctxt_tbl_old);
+
+       return 0;
 }
 
 /*
@@ -5002,9 +4972,9 @@ static int copy_context_tables(struct intel_iommu *iommu,
                if (!context_new_virt)
                        goto out_err;
 
-               ret = copy_from_oldmem_phys(context_new_virt, context_old_phys,
-                                           VTD_PAGE_SIZE);
-               if (ret != VTD_PAGE_SIZE) {
+               ret = copy_one_context_table(iommu, context_new_virt,
+                                            context_old_phys);
+               if (ret) {
                        pr_err("Failed to copy context table for bus %d from 
physical address 0x%llx\n",
                               bus, context_old_phys);
                        free_pgtable_page(context_new_virt);
-- 
1.9.1

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