[Xen-devel] [v4][PATCH 8/9] tools:firmware:hvmloader: check to reserve RMRR mappings in e820

[Tiejun Chen <tiejun.chen@xxxxxxxxx>]

We need to check to reserve all RMRR mappings in e820 to avoid any
potential guest memory conflict.

Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxx>
---
 tools/firmware/hvmloader/e820.c | 101 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 101 insertions(+)

diff --git a/tools/firmware/hvmloader/e820.c b/tools/firmware/hvmloader/e820.c
index 2e05e93..ae51fa6 100644
--- a/tools/firmware/hvmloader/e820.c
+++ b/tools/firmware/hvmloader/e820.c
@@ -68,12 +68,90 @@ void dump_e820_table(struct e820entry *e820, unsigned int 
nr)
     }
 }
 
+static unsigned int construct_rmrr_e820_maps(unsigned int nr,
+                                             uint32_t nr_map,
+                                             struct reserved_device_memory 
*map,
+                                             struct e820entry *e820)
+{
+    unsigned int i = 0, j = 0, m = 0, sum_nr = 0;
+    uint64_t start, end, rmrr_start, rmrr_end;
+    unsigned int insert = 0, do_insert = 0;
+
+do_real_construct:
+    sum_nr = nr + nr_map;
+    for ( i = 0; i < nr_map; i++ )
+    {
+        rmrr_start = map[i].pfn << PAGE_SHIFT;
+        rmrr_end = rmrr_start + map[i].count * PAGE_SIZE;
+
+        for ( j = 0; j < nr; j++ )
+        {
+            end = e820[j].addr + e820[j].size;
+            start = e820[j+1].addr;
+
+            /* Between those existing e820 entries. */
+            if ( (rmrr_start > end) && (rmrr_end < start) )
+            {
+                if (do_insert)
+                {
+                    /* Move to free this entry. */
+                    for ( m = sum_nr - 1; m > j; m-- )
+                    {
+                        e820[m].addr = e820[m-1].addr;
+                        e820[m].size = e820[m-1].size;
+                        e820[m].type = e820[m-1].type;
+                    }
+
+                    /* Then fill RMRR into that entry. */
+                    e820[j+1].addr = rmrr_start;
+                    e820[j+1].size = rmrr_end - rmrr_start;
+                    e820[j+1].type = E820_RESERVED;
+                    nr++;
+                }
+                insert++;
+            }
+            /* Already at the end. */
+            else if ( (rmrr_start > end) && !start )
+            {
+                if ( do_insert )
+                {
+                    e820[nr].addr = rmrr_start;
+                    e820[nr].size = rmrr_end - rmrr_start;
+                    e820[nr].type = E820_RESERVED;
+                    nr++;
+                }
+                insert++;
+            }
+        }
+    }
+
+    /* Just return if done. */
+    if ( do_insert )
+        return nr;
+
+    /* Fine to construct RMRR mappings into e820. */
+    if ( insert == nr_map)
+    {
+        do_insert = 1;
+        goto do_real_construct;
+    }
+    /* Overlap. */
+    else
+    {
+        printf("RMRR overlap with those existing e820 entries!\n");
+        printf("So we don't construct RMRR mapping in e820!\n");
+    }
+
+    return nr;
+}
 /* Create an E820 table based on memory parameters provided in hvm_info. */
 int build_e820_table(struct e820entry *e820,
                      unsigned int lowmem_reserved_base,
                      unsigned int bios_image_base)
 {
     unsigned int nr = 0;
+    struct reserved_device_memory *map = NULL;
+    int rc;
 
     if ( !lowmem_reserved_base )
             lowmem_reserved_base = 0xA0000;
@@ -169,6 +247,29 @@ int build_e820_table(struct e820entry *e820,
         nr++;
     }
 
+    /* We'd better reserve RMRR mapping for each VM to avoid potential
+     * memory conflict.
+     */
+    if ( hvm_info->nr_reserved_device_memory_map )
+    {
+        if ( !map )
+            map = mem_alloc(hvm_info->nr_reserved_device_memory_map * 
sizeof(struct reserved_device_memory), 0);
+        if ( map )
+        {
+            rc = get_reserved_device_memory_map(map,
+                                                
hvm_info->nr_reserved_device_memory_map);
+            if ( !rc )
+            {
+                nr = construct_rmrr_e820_maps(nr,
+                                              
hvm_info->nr_reserved_device_memory_map,
+                                              map,
+                                              e820);
+            }
+        }
+        else
+            printf("No space to get reserved_device_memory_map!\n");
+    }
+
     return nr;
 }
 
-- 
1.9.1


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