[Xen-devel] [RFC][v3][PATCH 3/6] tools:firmware:hvmloader: reserve RMRR mappings in e820

[Tiejun Chen <tiejun.chen@xxxxxxxxx>]

We need 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 | 94 +++++++++++++++++++++++++++++++++++++++++
 tools/firmware/hvmloader/e820.h |  6 +++
 tools/firmware/hvmloader/util.c | 16 +++++++
 tools/firmware/hvmloader/util.h |  2 +
 4 files changed, 118 insertions(+)

diff --git a/tools/firmware/hvmloader/e820.c b/tools/firmware/hvmloader/e820.c
index 2e05e93..7f54eab 100644
--- a/tools/firmware/hvmloader/e820.c
+++ b/tools/firmware/hvmloader/e820.c
@@ -68,12 +68,89 @@ void dump_e820_table(struct e820entry *e820, unsigned int 
nr)
     }
 }
 
+static unsigned int construct_rmrr_e820_maps(unsigned int nr,
+                                     struct rmrr_map *e820_rmrr_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 + e820_rmrr_map->nr_map;
+    for ( i = 0; i < e820_rmrr_map->nr_map; i++ )
+    {
+        rmrr_start = e820_rmrr_map->map[i].addr;
+        rmrr_end = e820_rmrr_map->map[i].addr +
+                   e820_rmrr_map->map[i].size + 1;
+
+        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 == e820_rmrr_map->nr_map)
+    {
+        do_insert = 1;
+        goto do_real_construct;
+    }
+    /* Overlap. */
+    else
+    {
+        printf("RMRR overlap with thoese 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 rmrr_map *rmrr_maps;
 
     if ( !lowmem_reserved_base )
             lowmem_reserved_base = 0xA0000;
@@ -169,6 +246,23 @@ int build_e820_table(struct e820entry *e820,
         nr++;
     }
 
+    /* We'd better reserve RMRR mapping for each VM to avoid potential
+     * memory conflict.
+     */
+    rmrr_maps = get_rmrr_map_info();
+    if ( rmrr_maps->nr_map )
+    {
+        if ( (nr + rmrr_maps->nr_map) > E820MAX )
+        {
+            printf(" No free space to insert all RMRR mapping entry!!\n");
+            return nr;
+        }
+        else
+        {
+            nr = construct_rmrr_e820_maps(nr, rmrr_maps, e820);
+        }
+    }
+
     return nr;
 }
 
diff --git a/tools/firmware/hvmloader/e820.h b/tools/firmware/hvmloader/e820.h
index b2ead7f..a61b80b 100644
--- a/tools/firmware/hvmloader/e820.h
+++ b/tools/firmware/hvmloader/e820.h
@@ -15,6 +15,12 @@ struct e820entry {
     uint32_t type;
 } __attribute__((packed));
 
+#define E820MAX 128
+
+struct rmrr_map {
+    unsigned int nr_map;
+    struct e820entry map[E820MAX];
+};
 #endif /* __HVMLOADER_E820_H__ */
 
 /*
diff --git a/tools/firmware/hvmloader/util.c b/tools/firmware/hvmloader/util.c
index 80d822f..f63434a 100644
--- a/tools/firmware/hvmloader/util.c
+++ b/tools/firmware/hvmloader/util.c
@@ -766,6 +766,22 @@ struct shared_info *get_shared_info(void)
     return shared_info;
 }
 
+struct rmrr_map *get_rmrr_map_info(void)
+{
+    static int no_rmrr = 1;
+
+    if ( no_rmrr == 0 )
+        return &rmrr_e820map;
+
+    if ( hypercall_memory_op(XENMEM_reserved_device_memory_map,
+                             &rmrr_e820map) != 0 )
+        BUG();
+
+    no_rmrr = 0;
+
+    return &rmrr_e820map;
+}
+
 uint16_t get_cpu_mhz(void)
 {
     struct shared_info *shared_info = get_shared_info();
diff --git a/tools/firmware/hvmloader/util.h b/tools/firmware/hvmloader/util.h
index a70e4aa..5f48a86 100644
--- a/tools/firmware/hvmloader/util.h
+++ b/tools/firmware/hvmloader/util.h
@@ -236,6 +236,8 @@ unsigned long create_pir_tables(void);
 void smp_initialise(void);
 
 #include "e820.h"
+struct rmrr_map rmrr_e820map;
+struct rmrr_map *get_rmrr_map_info(void);
 int build_e820_table(struct e820entry *e820,
                      unsigned int lowmem_reserved_base,
                      unsigned int bios_image_base);
-- 
1.9.1


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