[Xen-devel] [PATCH] VT-d: correct allocation failure checks

["Jan Beulich" <jbeulich@xxxxxxxxxx>]

Checking the return value of map_domain_page() (and hence
map_vtd_domain_page()) against NULL is pointless, checking the return
value of alloc_domheap_page() (and thus alloc_pgtable_maddr()) is
mandatory, however.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

Index: 2008-09-19/xen/drivers/passthrough/vtd/intremap.c
===================================================================
--- 2008-09-19.orig/xen/drivers/passthrough/vtd/intremap.c      2008-08-29 
14:26:56.000000000 +0200
+++ 2008-09-19/xen/drivers/passthrough/vtd/intremap.c   2008-10-17 
15:28:46.000000000 +0200
@@ -469,7 +469,7 @@ int intremap_setup(struct iommu *iommu)
         {
             dprintk(XENLOG_WARNING VTDPREFIX,
                     "Cannot allocate memory for ir_ctrl->iremap_maddr\n");
-            return -ENODEV;
+            return -ENOMEM;
         }
         ir_ctrl->iremap_index = -1;
     }
Index: 2008-09-19/xen/drivers/passthrough/vtd/iommu.c
===================================================================
--- 2008-09-19.orig/xen/drivers/passthrough/vtd/iommu.c 2008-09-17 
09:26:41.000000000 +0200
+++ 2008-09-19/xen/drivers/passthrough/vtd/iommu.c      2008-10-17 
15:24:55.000000000 +0200
@@ -220,10 +220,10 @@ static u64 addr_to_dma_page_maddr(struct
             if ( !alloc )
                 break;
             maddr = alloc_pgtable_maddr();
+            if ( !maddr )
+                break;
             dma_set_pte_addr(*pte, maddr);
             vaddr = map_vtd_domain_page(maddr);
-            if ( !vaddr )
-                break;
 
             /*
              * high level table always sets r/w, last level
@@ -236,8 +236,6 @@ static u64 addr_to_dma_page_maddr(struct
         else
         {
             vaddr = map_vtd_domain_page(pte->val);
-            if ( !vaddr )
-                break;
         }
 
         if ( level == 2 )
Index: 2008-09-19/xen/drivers/passthrough/vtd/qinval.c
===================================================================
--- 2008-09-19.orig/xen/drivers/passthrough/vtd/qinval.c        2008-07-18 
16:19:34.000000000 +0200
+++ 2008-09-19/xen/drivers/passthrough/vtd/qinval.c     2008-10-17 
15:29:24.000000000 +0200
@@ -429,7 +429,11 @@ int qinval_setup(struct iommu *iommu)
     {
         qi_ctrl->qinval_maddr = alloc_pgtable_maddr();
         if ( qi_ctrl->qinval_maddr == 0 )
-            panic("Cannot allocate memory for qi_ctrl->qinval_maddr\n");
+        {
+            dprintk(XENLOG_WARNING VTDPREFIX,
+                    "Cannot allocate memory for qi_ctrl->qinval_maddr\n");
+            return -ENOMEM;
+        }
         flush->context = flush_context_qi;
         flush->iotlb = flush_iotlb_qi;
     }
Index: 2008-09-19/xen/drivers/passthrough/vtd/x86/vtd.c
===================================================================
--- 2008-09-19.orig/xen/drivers/passthrough/vtd/x86/vtd.c       2008-06-02 
09:52:09.000000000 +0200
+++ 2008-09-19/xen/drivers/passthrough/vtd/x86/vtd.c    2008-10-17 
15:20:46.000000000 +0200
@@ -41,17 +41,19 @@ u64 alloc_pgtable_maddr(void)
 {
     struct page_info *pg;
     u64 *vaddr;
+    unsigned long mfn;
 
     pg = alloc_domheap_page(NULL, 0);
-    vaddr = map_domain_page(page_to_mfn(pg));
-    if ( !vaddr )
+    if ( !pg )
         return 0;
+    mfn = page_to_mfn(pg);
+    vaddr = map_domain_page(mfn);
     memset(vaddr, 0, PAGE_SIZE);
 
     iommu_flush_cache_page(vaddr);
     unmap_domain_page(vaddr);
 
-    return page_to_maddr(pg);
+    return (u64)mfn << PAGE_SHIFT_4K;
 }
 
 void free_pgtable_maddr(u64 maddr)




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