[Qemu-arm] [RFC PATCH v1 3/4] translate-all.c: Compute L1 page table properties at runtime

[vijayak]

From: Vijaya Kumar K <address@hidden>

Remove L1 page mapping table properties computing
statically using macros which is dependent on
TARGET_PAGE_BITS. Drop macros V_L1_SIZE, V_L1_SHIFT,
V_L1_BITS macros and replace with variables which are
computed at early stage of VM boot.

Removing dependency can help to make TARGET_PAGE_BITS
dynamic.

Signed-off-by: Vijaya Kumar K <address@hidden>
---
 include/qemu-common.h |    1 +
 translate-all.c       |   57 ++++++++++++++++++++++++++++++-------------------
 vl.c                  |    3 +++
 3 files changed, 39 insertions(+), 22 deletions(-)

diff --git a/include/qemu-common.h b/include/qemu-common.h
index 1f2cb94..d5f0450 100644
--- a/include/qemu-common.h
+++ b/include/qemu-common.h
@@ -129,6 +129,7 @@ int parse_debug_env(const char *name, int max, int initial);
 
 const char *qemu_ether_ntoa(const MACAddr *mac);
 void page_size_init(void);
+void init_l1_page_table_param(void);
 
 /* returns non-zero if dump is in progress, otherwise zero is
  * returned. */
diff --git a/translate-all.c b/translate-all.c
index 118e7d3..a580ca9 100644
--- a/translate-all.c
+++ b/translate-all.c
@@ -57,6 +57,7 @@
 #include "qemu/bitmap.h"
 #include "qemu/timer.h"
 #include "exec/log.h"
+#include "qemu/error-report.h"
 
 //#define DEBUG_TB_INVALIDATE
 //#define DEBUG_FLUSH
@@ -99,25 +100,18 @@ typedef struct PageDesc {
 #define V_L2_BITS 10
 #define V_L2_SIZE (1 << V_L2_BITS)
 
-/* The bits remaining after N lower levels of page tables.  */
-#define V_L1_BITS_REM \
-    ((L1_MAP_ADDR_SPACE_BITS - TARGET_PAGE_BITS) % V_L2_BITS)
-
-#if V_L1_BITS_REM < 4
-#define V_L1_BITS  (V_L1_BITS_REM + V_L2_BITS)
-#else
-#define V_L1_BITS  V_L1_BITS_REM
-#endif
-
-#define V_L1_SIZE  ((target_ulong)1 << V_L1_BITS)
-
-#define V_L1_SHIFT (L1_MAP_ADDR_SPACE_BITS - TARGET_PAGE_BITS - V_L1_BITS)
-
 uintptr_t qemu_host_page_size;
 intptr_t qemu_host_page_mask;
 
+/*
+ * L1 Mapping properties
+ */
+static unsigned long v_l1_bits;
+static unsigned long v_l1_size;
+static unsigned long v_l1_shift;
+
 /* The bottom level has pointers to PageDesc */
-static void *l1_map[V_L1_SIZE];
+static void *l1_map;
 
 /* code generation context */
 TCGContext tcg_ctx;
@@ -127,6 +121,25 @@ TCGContext tcg_ctx;
 __thread int have_tb_lock;
 #endif
 
+void init_l1_page_table_param(void)
+{
+    uint32_t v_l1_bits_rem;
+
+    assert(TARGET_PAGE_BITS);
+    /* The bits remaining after N lower levels of page tables.  */
+    v_l1_bits_rem = ((L1_MAP_ADDR_SPACE_BITS - TARGET_PAGE_BITS) % V_L2_BITS);
+    if (v_l1_bits_rem < 4)
+        v_l1_bits = (v_l1_bits_rem + V_L2_BITS);
+    else
+        v_l1_bits = v_l1_bits_rem;
+
+    v_l1_size = ((target_ulong)1 << v_l1_bits);
+    v_l1_shift = (L1_MAP_ADDR_SPACE_BITS - TARGET_PAGE_BITS - v_l1_bits);
+    l1_map = g_malloc0(v_l1_size * sizeof(void *));
+    if (!l1_map)
+        error_report("Allocation faile for L1 MAP table\n");
+}
+
 void tb_lock(void)
 {
 #ifdef CONFIG_USER_ONLY
@@ -408,10 +421,10 @@ static PageDesc *page_find_alloc(tb_page_addr_t index, 
int alloc)
     int i;
 
     /* Level 1.  Always allocated.  */
-    lp = l1_map + ((index >> V_L1_SHIFT) & (V_L1_SIZE - 1));
+    lp = l1_map + ((index >> v_l1_shift) & (v_l1_size - 1));
 
     /* Level 2..N-1.  */
-    for (i = V_L1_SHIFT / V_L2_BITS - 1; i > 0; i--) {
+    for (i = v_l1_shift / V_L2_BITS - 1; i > 0; i--) {
         void **p = atomic_rcu_read(lp);
 
         if (p == NULL) {
@@ -819,8 +832,8 @@ static void page_flush_tb(void)
 {
     int i;
 
-    for (i = 0; i < V_L1_SIZE; i++) {
-        page_flush_tb_1(V_L1_SHIFT / V_L2_BITS - 1, l1_map + i);
+    for (i = 0; i < v_l1_size; i++) {
+        page_flush_tb_1(v_l1_shift / V_L2_BITS - 1, l1_map + i);
     }
 }
 
@@ -1825,9 +1838,9 @@ int walk_memory_regions(void *priv, 
walk_memory_regions_fn fn)
     data.start = -1u;
     data.prot = 0;
 
-    for (i = 0; i < V_L1_SIZE; i++) {
-        int rc = walk_memory_regions_1(&data, (target_ulong)i << (V_L1_SHIFT + 
TARGET_PAGE_BITS),
-                                       V_L1_SHIFT / V_L2_BITS - 1, l1_map + i);
+    for (i = 0; i < v_l1_size; i++) {
+        int rc = walk_memory_regions_1(&data, (target_ulong)i << (v_l1_shift + 
TARGET_PAGE_BITS),
+                                       v_l1_shift / V_L2_BITS - 1, l1_map + i);
         if (rc != 0) {
             return rc;
         }
diff --git a/vl.c b/vl.c
index b0bcc25..b6da265 100644
--- a/vl.c
+++ b/vl.c
@@ -4044,6 +4044,9 @@ int main(int argc, char **argv, char **envp)
     }
     object_property_add_child(object_get_root(), "machine",
                               OBJECT(current_machine), &error_abort);
+
+    init_l1_page_table_param();
+
     cpu_exec_init_all();
 
     if (machine_class->hw_version) {
-- 
1.7.9.5