Re: [Qemu-devel] [PATCH] Save 3MB ioport table memory

[Samuel Thibault <samuel.thibault@eu.citrix.com>]

Anthony Liguori, le Tue 22 Jul 2008 20:52:27 -0500, a écrit :
>  You have some whitespace damage (tabs instead of 8 spaces)

I need to configure vim to autodetect the tab style according to the
already existing content :)

> Perhaps you can introduce an accessor?
> 
> That would simplify the rest of the changes significantly.

It does indeed.




Save 1.5MB (32bit) or 3MB (64bit) memory by keeping ioport tables
sparse and use a test against NULL instead.

Signed-off-by: Samuel Thibault <samuel.thibault@eu.citrix.com>

Index: vl.c
===================================================================
--- vl.c	(révision 4917)
+++ vl.c	(copie de travail)
@@ -260,6 +260,35 @@
 target_phys_addr_t isa_mem_base = 0;
 PicState2 *isa_pic;
 
+static IOPortReadFunc default_ioport_readb, default_ioport_readw, default_ioport_readl;
+static IOPortWriteFunc default_ioport_writeb, default_ioport_writew, default_ioport_writel;
+
+static uint32_t default_ioport_readi(int index, uint32_t address)
+{
+    static IOPortReadFunc *default_func[3] = {
+        default_ioport_readb,
+        default_ioport_readw,
+        default_ioport_readl
+    };
+    IOPortReadFunc *func = ioport_read_table[index][address];
+    if (!func)
+        func = default_func[index];
+    return func(ioport_opaque[address], address);
+}
+
+static void default_ioport_writei(int index, uint32_t address, uint32_t data)
+{
+    static IOPortWriteFunc *default_func[3] = {
+        default_ioport_writeb,
+        default_ioport_writew,
+        default_ioport_writel
+    };
+    IOPortWriteFunc *func = ioport_write_table[index][address];
+    if (!func)
+        func = default_func[index];
+    func(ioport_opaque[address], address, data);
+}
+
 static uint32_t default_ioport_readb(void *opaque, uint32_t address)
 {
 #ifdef DEBUG_UNUSED_IOPORT
@@ -279,17 +308,17 @@
 static uint32_t default_ioport_readw(void *opaque, uint32_t address)
 {
     uint32_t data;
-    data = ioport_read_table[0][address](ioport_opaque[address], address);
+    data = default_ioport_readi(0, address);
     address = (address + 1) & (MAX_IOPORTS - 1);
-    data |= ioport_read_table[0][address](ioport_opaque[address], address) << 8;
+    data |= default_ioport_readi(0, address) << 8;
     return data;
 }
 
 static void default_ioport_writew(void *opaque, uint32_t address, uint32_t data)
 {
-    ioport_write_table[0][address](ioport_opaque[address], address, data & 0xff);
+    default_ioport_writei(0, address, data & 0xff);
     address = (address + 1) & (MAX_IOPORTS - 1);
-    ioport_write_table[0][address](ioport_opaque[address], address, (data >> 8) & 0xff);
+    default_ioport_writei(0, address, (data >> 8) & 0xff);
 }
 
 static uint32_t default_ioport_readl(void *opaque, uint32_t address)
@@ -309,16 +338,6 @@
 
 static void init_ioports(void)
 {
-    int i;
-
-    for(i = 0; i < MAX_IOPORTS; i++) {
-        ioport_read_table[0][i] = default_ioport_readb;
-        ioport_write_table[0][i] = default_ioport_writeb;
-        ioport_read_table[1][i] = default_ioport_readw;
-        ioport_write_table[1][i] = default_ioport_writew;
-        ioport_read_table[2][i] = default_ioport_readl;
-        ioport_write_table[2][i] = default_ioport_writel;
-    }
 }
 
 /* size is the word size in byte */
@@ -394,7 +413,7 @@
     if (loglevel & CPU_LOG_IOPORT)
         fprintf(logfile, "outb: %04x %02x\n", addr, val);
 #endif
-    ioport_write_table[0][addr](ioport_opaque[addr], addr, val);
+    default_ioport_writei(0, addr, val);
 #ifdef USE_KQEMU
     if (env)
         env->last_io_time = cpu_get_time_fast();
@@ -407,7 +426,7 @@
     if (loglevel & CPU_LOG_IOPORT)
         fprintf(logfile, "outw: %04x %04x\n", addr, val);
 #endif
-    ioport_write_table[1][addr](ioport_opaque[addr], addr, val);
+    default_ioport_writei(1, addr, val);
 #ifdef USE_KQEMU
     if (env)
         env->last_io_time = cpu_get_time_fast();
@@ -420,7 +439,7 @@
     if (loglevel & CPU_LOG_IOPORT)
         fprintf(logfile, "outl: %04x %08x\n", addr, val);
 #endif
-    ioport_write_table[2][addr](ioport_opaque[addr], addr, val);
+    default_ioport_writei(2, addr, val);
 #ifdef USE_KQEMU
     if (env)
         env->last_io_time = cpu_get_time_fast();
@@ -430,7 +449,7 @@
 int cpu_inb(CPUState *env, int addr)
 {
     int val;
-    val = ioport_read_table[0][addr](ioport_opaque[addr], addr);
+    val = default_ioport_readi(0, addr);
 #ifdef DEBUG_IOPORT
     if (loglevel & CPU_LOG_IOPORT)
         fprintf(logfile, "inb : %04x %02x\n", addr, val);
@@ -445,7 +464,7 @@
 int cpu_inw(CPUState *env, int addr)
 {
     int val;
-    val = ioport_read_table[1][addr](ioport_opaque[addr], addr);
+    val = default_ioport_readi(1, addr);
 #ifdef DEBUG_IOPORT
     if (loglevel & CPU_LOG_IOPORT)
         fprintf(logfile, "inw : %04x %04x\n", addr, val);
@@ -460,7 +479,7 @@
 int cpu_inl(CPUState *env, int addr)
 {
     int val;
-    val = ioport_read_table[2][addr](ioport_opaque[addr], addr);
+    val = default_ioport_readi(2, addr);
 #ifdef DEBUG_IOPORT
     if (loglevel & CPU_LOG_IOPORT)
         fprintf(logfile, "inl : %04x %08x\n", addr, val);