[Xen-devel] [v6][PATCH 3/7] tools/libxc: check if mmio BAR is out of reserved device memory maps

[Tiejun Chen <tiejun.chen@xxxxxxxxx>]

We need to avoid allocating MMIO BAR conflicting to all reserved device
memory range.

Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxx>

diff --git a/tools/libxc/xc_hvm_build_x86.c b/tools/libxc/xc_hvm_build_x86.c
index c81a25b..299e33a 100644
--- a/tools/libxc/xc_hvm_build_x86.c
+++ b/tools/libxc/xc_hvm_build_x86.c
@@ -239,6 +239,73 @@ static int check_mmio_hole(uint64_t start, uint64_t 
memsize,
         return 1;
 }
 
+/*
+ * Check whether there exists mmio overplap with the reserved device
+ * memory map
+ */
+static int check_rdm_overlap(xc_interface *xch, uint64_t mmio_start,
+                             uint64_t mmio_size)
+{
+    struct xen_mem_reserved_device_memory *map = NULL;
+    uint64_t rdm_start = 0, rdm_end = 0;
+    unsigned int i = 0;
+    int rc = 0;
+    /* Assume we have one entry if not enough we'll expand.*/
+    uint32_t nr_entries = 1;
+
+    /* We should check if mmio range is out of RDM mapping. */
+    if ( (map = malloc(nr_entries *
+                       sizeof(xen_mem_reserved_device_memory_t))) == NULL )
+    {
+        PERROR("Could not allocate memory for map.");
+        return -1;
+    }
+    rc = xc_reserved_device_memory_map(xch, map, &nr_entries);
+    if ( rc < 0 )
+    {
+        /* DRM doesn't exist. */
+        if ( rc == -ENOENT )
+            rc = 0;
+        else if ( rc == -ENOBUFS)
+        {
+            free(map);
+            /* Now we need more space to map all RDM mappings. */
+            if ( (map = malloc(nr_entries *
+                               sizeof(xen_mem_reserved_device_memory_t))) == 
NULL )
+            {
+                PERROR("Could not allocate memory for map.");
+                return -1;
+            }
+            rc = xc_reserved_device_memory_map(xch, map, &nr_entries);
+            if ( rc < 0 )
+            {
+                PERROR("Could not get DRM info on domain");
+                free(map);
+                return rc;
+            }
+        }
+        else
+            PERROR("Could not get RDM info on domain");
+    }
+
+    for ( i = 0; i < rc; i++ )
+    {
+        rdm_start = map[i].start_pfn << PAGE_SHIFT;
+        rdm_end = rdm_start + map[i].nr_pages * PAGE_SIZE;
+        if ( check_mmio_hole(rdm_start, map[i].nr_pages * PAGE_SIZE,
+                             mmio_start, mmio_size) )
+        {
+            PERROR("MMIO: [%lx]<->[%lx] overlap DRM [%lx]<->[%lx]\n",
+                   mmio_start, (mmio_start + mmio_size), rdm_start, rdm_end);
+            free(map);
+            return -1;
+        }
+    }
+
+    free(map);
+    return rc;
+}
+
 static int setup_guest(xc_interface *xch,
                        uint32_t dom, struct xc_hvm_build_args *args,
                        char *image, unsigned long image_size)
@@ -300,6 +367,10 @@ static int setup_guest(xc_interface *xch,
         goto error_out;
     }
 
+    rc = check_rdm_overlap(xch, mmio_start, mmio_start);
+    if ( rc < 0 )
+        goto error_out;
+
     for ( i = 0; i < nr_pages; i++ )
         page_array[i] = i;
     for ( i = mmio_start >> PAGE_SHIFT; i < nr_pages; i++ )
-- 
1.9.1


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