* [Qemu-devel] [PATCH] memory usage and ioports
2007-11-19 15:20 [Qemu-devel] memory usage and ioports Samuel Thibault
2007-11-19 15:34 ` [Qemu-devel] " Samuel Thibault
@ 2008-02-06 14:24 ` Samuel Thibault
1 sibling, 0 replies; 5+ messages in thread
From: Samuel Thibault @ 2008-02-06 14:24 UTC (permalink / raw)
To: qemu-devel
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Samuel Thibault, le Mon 19 Nov 2007 15:20:16 +0000, a écrit :
> Qemu currently uses 6 65k tables of pointers for handling ioports, which
> makes 3MB on 64bit machines. There's a comment that says "XXX: use a two
> level table to limit memory usage". But wouldn't it be more simple and
> effective to just allocate them through mmap() and when a NULL pointer
> is read, call the default handlers?
Here is a patch that does this and indeed saves 3MB on 64bit machines.
Samuel
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? ChangeLog
Index: vl.c
===================================================================
RCS file: /sources/qemu/qemu/vl.c,v
retrieving revision 1.403
diff -u -p -r1.403 vl.c
--- vl.c 3 Feb 2008 03:45:47 -0000 1.403
+++ vl.c 6 Feb 2008 14:22:18 -0000
@@ -267,17 +267,29 @@ static void default_ioport_writeb(void *
static uint32_t default_ioport_readw(void *opaque, uint32_t address)
{
uint32_t data;
- data = ioport_read_table[0][address](ioport_opaque[address], address);
+ IOPortReadFunc *func = ioport_read_table[0][address];
+ if (!func)
+ func = default_ioport_readb;
+ data = func(ioport_opaque[address], address);
address = (address + 1) & (MAX_IOPORTS - 1);
- data |= ioport_read_table[0][address](ioport_opaque[address], address) << 8;
+ func = ioport_read_table[0][address];
+ if (!func)
+ func = default_ioport_readb;
+ data |= func(ioport_opaque[address], 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);
+ IOPortWriteFunc *func = ioport_write_table[0][address];
+ if (!func)
+ func = default_ioport_writeb;
+ func(ioport_opaque[address], address, data & 0xff);
address = (address + 1) & (MAX_IOPORTS - 1);
- ioport_write_table[0][address](ioport_opaque[address], address, (data >> 8) & 0xff);
+ func = ioport_write_table[0][address];
+ if (!func)
+ func = default_ioport_writeb;
+ func(ioport_opaque[address], address, (data >> 8) & 0xff);
}
static uint32_t default_ioport_readl(void *opaque, uint32_t address)
@@ -297,16 +309,6 @@ static void default_ioport_writel(void *
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 */
@@ -378,11 +380,14 @@ void isa_unassign_ioport(int start, int
void cpu_outb(CPUState *env, int addr, int val)
{
+ IOPortWriteFunc *func = ioport_write_table[0][addr];
+ if (!func)
+ func = default_ioport_writeb;
#ifdef DEBUG_IOPORT
if (loglevel & CPU_LOG_IOPORT)
fprintf(logfile, "outb: %04x %02x\n", addr, val);
#endif
- ioport_write_table[0][addr](ioport_opaque[addr], addr, val);
+ func(ioport_opaque[addr], addr, val);
#ifdef USE_KQEMU
if (env)
env->last_io_time = cpu_get_time_fast();
@@ -391,11 +396,14 @@ void cpu_outb(CPUState *env, int addr, i
void cpu_outw(CPUState *env, int addr, int val)
{
+ IOPortWriteFunc *func = ioport_write_table[1][addr];
+ if (!func)
+ func = default_ioport_writew;
#ifdef DEBUG_IOPORT
if (loglevel & CPU_LOG_IOPORT)
fprintf(logfile, "outw: %04x %04x\n", addr, val);
#endif
- ioport_write_table[1][addr](ioport_opaque[addr], addr, val);
+ func(ioport_opaque[addr], addr, val);
#ifdef USE_KQEMU
if (env)
env->last_io_time = cpu_get_time_fast();
@@ -404,11 +412,14 @@ void cpu_outw(CPUState *env, int addr, i
void cpu_outl(CPUState *env, int addr, int val)
{
+ IOPortWriteFunc *func = ioport_write_table[2][addr];
+ if (!func)
+ func = default_ioport_writel;
#ifdef DEBUG_IOPORT
if (loglevel & CPU_LOG_IOPORT)
fprintf(logfile, "outl: %04x %08x\n", addr, val);
#endif
- ioport_write_table[2][addr](ioport_opaque[addr], addr, val);
+ func(ioport_opaque[addr], addr, val);
#ifdef USE_KQEMU
if (env)
env->last_io_time = cpu_get_time_fast();
@@ -418,7 +429,10 @@ void cpu_outl(CPUState *env, int addr, i
int cpu_inb(CPUState *env, int addr)
{
int val;
- val = ioport_read_table[0][addr](ioport_opaque[addr], addr);
+ IOPortReadFunc *func = ioport_read_table[0][addr];
+ if (!func)
+ func = default_ioport_readb;
+ val = func(ioport_opaque[addr], addr);
#ifdef DEBUG_IOPORT
if (loglevel & CPU_LOG_IOPORT)
fprintf(logfile, "inb : %04x %02x\n", addr, val);
@@ -433,7 +447,10 @@ int cpu_inb(CPUState *env, int addr)
int cpu_inw(CPUState *env, int addr)
{
int val;
- val = ioport_read_table[1][addr](ioport_opaque[addr], addr);
+ IOPortReadFunc *func = ioport_read_table[1][addr];
+ if (!func)
+ func = default_ioport_readw;
+ val = func(ioport_opaque[addr], addr);
#ifdef DEBUG_IOPORT
if (loglevel & CPU_LOG_IOPORT)
fprintf(logfile, "inw : %04x %04x\n", addr, val);
@@ -448,7 +465,10 @@ int cpu_inw(CPUState *env, int addr)
int cpu_inl(CPUState *env, int addr)
{
int val;
- val = ioport_read_table[2][addr](ioport_opaque[addr], addr);
+ IOPortReadFunc *func = ioport_read_table[2][addr];
+ if (!func)
+ func = default_ioport_readl;
+ val = func(ioport_opaque[addr], addr);
#ifdef DEBUG_IOPORT
if (loglevel & CPU_LOG_IOPORT)
fprintf(logfile, "inl : %04x %08x\n", addr, val);
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