diff --git a/cpu-all.h b/cpu-all.h
index a4dee21..2740da9 100644
--- a/cpu-all.h
+++ b/cpu-all.h
@@ -806,12 +806,20 @@
 int cpu_inl(CPUState *env, int addr);
 #endif
 
+/* address in the RAM (different from a physical address) */
+#ifdef USE_KQEMU
+typedef uint32_t ram_addr_t;
+#else
+typedef unsigned long ram_addr_t;
+#endif
+
 /* memory API */
 
-extern int phys_ram_size;
+extern ram_addr_t phys_ram_size;
 extern int phys_ram_fd;
 extern uint8_t *phys_ram_base;
 extern uint8_t *phys_ram_dirty;
+extern ram_addr_t ram_size;
 
 /* physical memory access */
 #define TLB_INVALID_MASK   (1 << 3)
@@ -833,10 +841,10 @@
 typedef uint32_t CPUReadMemoryFunc(void *opaque, target_phys_addr_t addr);
 
 void cpu_register_physical_memory(target_phys_addr_t start_addr,
-                                  unsigned long size,
-                                  unsigned long phys_offset);
-uint32_t cpu_get_physical_page_desc(target_phys_addr_t addr);
-ram_addr_t qemu_ram_alloc(unsigned int size);
+                                  ram_addr_t size,
+                                  ram_addr_t phys_offset);
+ram_addr_t cpu_get_physical_page_desc(target_phys_addr_t addr);
+ram_addr_t qemu_ram_alloc(ram_addr_t);
 void qemu_ram_free(ram_addr_t addr);
 int cpu_register_io_memory(int io_index,
                            CPUReadMemoryFunc **mem_read,
diff --git a/cpu-defs.h b/cpu-defs.h
index 1591748..c4389ed 100644
--- a/cpu-defs.h
+++ b/cpu-defs.h
@@ -76,9 +76,6 @@
 #error TARGET_PHYS_ADDR_BITS undefined
 #endif
 
-/* address in the RAM (different from a physical address) */
-typedef unsigned long ram_addr_t;
-
 #define HOST_LONG_SIZE (HOST_LONG_BITS / 8)
 
 #define EXCP_INTERRUPT 	0x10000 /* async interruption */
diff --git a/exec-all.h b/exec-all.h
index 898cf68..47bdddd 100644
--- a/exec-all.h
+++ b/exec-all.h
@@ -82,7 +82,7 @@
 void cpu_resume_from_signal(CPUState *env1, void *puc);
 void cpu_exec_init(CPUState *env);
 int page_unprotect(target_ulong address, unsigned long pc, void *puc);
-void tb_invalidate_phys_page_range(target_ulong start, target_ulong end,
+void tb_invalidate_phys_page_range(target_phys_addr_t start, target_phys_addr_t end,
                                    int is_cpu_write_access);
 void tb_invalidate_page_range(target_ulong start, target_ulong end);
 void tlb_flush_page(CPUState *env, target_ulong addr);
diff --git a/exec.c b/exec.c
index 0940137..d011cce 100644
--- a/exec.c
+++ b/exec.c
@@ -74,6 +74,10 @@
 #define TARGET_VIRT_ADDR_SPACE_BITS 42
 #elif defined(TARGET_PPC64)
 #define TARGET_PHYS_ADDR_SPACE_BITS 42
+#elif defined(TARGET_X86_64) && !defined(USE_KQEMU)
+#define TARGET_PHYS_ADDR_SPACE_BITS 42
+#elif defined(TARGET_I386) && !defined(USE_KQEMU)
+#define TARGET_PHYS_ADDR_SPACE_BITS 36
 #else
 /* Note: for compatibility with kqemu, we use 32 bits for x86_64 */
 #define TARGET_PHYS_ADDR_SPACE_BITS 32
@@ -88,7 +92,7 @@
 uint8_t code_gen_buffer[CODE_GEN_BUFFER_SIZE] __attribute__((aligned (32)));
 uint8_t *code_gen_ptr;
 
-int phys_ram_size;
+ram_addr_t phys_ram_size;
 int phys_ram_fd;
 uint8_t *phys_ram_base;
 uint8_t *phys_ram_dirty;
@@ -113,7 +117,7 @@
 
 typedef struct PhysPageDesc {
     /* offset in host memory of the page + io_index in the low 12 bits */
-    uint32_t phys_offset;
+    ram_addr_t phys_offset;
 } PhysPageDesc;
 
 #define L2_BITS 10
@@ -234,7 +238,7 @@
 #endif
 }
 
-static inline PageDesc *page_find_alloc(unsigned int index)
+static inline PageDesc *page_find_alloc(target_ulong index)
 {
     PageDesc **lp, *p;
 
@@ -249,7 +253,7 @@
     return p + (index & (L2_SIZE - 1));
 }
 
-static inline PageDesc *page_find(unsigned int index)
+static inline PageDesc *page_find(target_ulong index)
 {
     PageDesc *p;
 
@@ -511,12 +515,12 @@
     tb_set_jmp_target(tb, n, (unsigned long)(tb->tc_ptr + tb->tb_next_offset[n]));
 }
 
-static inline void tb_phys_invalidate(TranslationBlock *tb, unsigned int page_addr)
+static inline void tb_phys_invalidate(TranslationBlock *tb, target_ulong page_addr)
 {
     CPUState *env;
     PageDesc *p;
     unsigned int h, n1;
-    target_ulong phys_pc;
+    target_phys_addr_t phys_pc;
     TranslationBlock *tb1, *tb2;
 
     /* remove the TB from the hash list */
@@ -667,7 +671,7 @@
    the same physical page. 'is_cpu_write_access' should be true if called
    from a real cpu write access: the virtual CPU will exit the current
    TB if code is modified inside this TB. */
-void tb_invalidate_phys_page_range(target_ulong start, target_ulong end,
+void tb_invalidate_phys_page_range(target_phys_addr_t start, target_phys_addr_t end,
                                    int is_cpu_write_access)
 {
     int n, current_tb_modified, current_tb_not_found, current_flags;
@@ -780,7 +784,7 @@
 }
 
 /* len must be <= 8 and start must be a multiple of len */
-static inline void tb_invalidate_phys_page_fast(target_ulong start, int len)
+static inline void tb_invalidate_phys_page_fast(target_phys_addr_t start, int len)
 {
     PageDesc *p;
     int offset, b;
@@ -809,7 +813,7 @@
 }
 
 #if !defined(CONFIG_SOFTMMU)
-static void tb_invalidate_phys_page(target_ulong addr,
+static void tb_invalidate_phys_page(target_phys_addr_t addr,
                                     unsigned long pc, void *puc)
 {
     int n, current_flags, current_tb_modified;
@@ -1985,9 +1989,9 @@
 #endif /* defined(CONFIG_USER_ONLY) */
 
 static int subpage_register (subpage_t *mmio, uint32_t start, uint32_t end,
-                             int memory);
-static void *subpage_init (target_phys_addr_t base, uint32_t *phys,
-                           int orig_memory);
+                             ram_addr_t memory);
+static void *subpage_init (target_phys_addr_t base, ram_addr_t *phys,
+                           ram_addr_t orig_memory);
 #define CHECK_SUBPAGE(addr, start_addr, start_addr2, end_addr, end_addr2, \
                       need_subpage)                                     \
     do {                                                                \
@@ -2012,13 +2016,13 @@
    page size. If (phys_offset & ~TARGET_PAGE_MASK) != 0, then it is an
    io memory page */
 void cpu_register_physical_memory(target_phys_addr_t start_addr,
-                                  unsigned long size,
-                                  unsigned long phys_offset)
+                                  ram_addr_t size,
+                                  ram_addr_t phys_offset)
 {
     target_phys_addr_t addr, end_addr;
     PhysPageDesc *p;
     CPUState *env;
-    unsigned long orig_size = size;
+    ram_addr_t orig_size = size;
     void *subpage;
 
     size = (size + TARGET_PAGE_SIZE - 1) & TARGET_PAGE_MASK;
@@ -2026,7 +2030,7 @@
     for(addr = start_addr; addr != end_addr; addr += TARGET_PAGE_SIZE) {
         p = phys_page_find(addr >> TARGET_PAGE_BITS);
         if (p && p->phys_offset != IO_MEM_UNASSIGNED) {
-            unsigned long orig_memory = p->phys_offset;
+            ram_addr_t orig_memory = p->phys_offset;
             target_phys_addr_t start_addr2, end_addr2;
             int need_subpage = 0;
 
@@ -2079,7 +2083,7 @@
 }
 
 /* XXX: temporary until new memory mapping API */
-uint32_t cpu_get_physical_page_desc(target_phys_addr_t addr)
+ram_addr_t cpu_get_physical_page_desc(target_phys_addr_t addr)
 {
     PhysPageDesc *p;
 
@@ -2090,11 +2094,11 @@
 }
 
 /* XXX: better than nothing */
-ram_addr_t qemu_ram_alloc(unsigned int size)
+ram_addr_t qemu_ram_alloc(ram_addr_t size)
 {
     ram_addr_t addr;
     if ((phys_ram_alloc_offset + size) > phys_ram_size) {
-        fprintf(stderr, "Not enough memory (requested_size = %u, max memory = %d)\n",
+        fprintf(stderr, "Not enough memory (requested_size = %lu, max memory = %ld)\n",
                 size, phys_ram_size);
         abort();
     }
@@ -2408,7 +2412,7 @@
 };
 
 static int subpage_register (subpage_t *mmio, uint32_t start, uint32_t end,
-                             int memory)
+                             ram_addr_t memory)
 {
     int idx, eidx;
     unsigned int i;
@@ -2438,8 +2442,8 @@
     return 0;
 }
 
-static void *subpage_init (target_phys_addr_t base, uint32_t *phys,
-                           int orig_memory)
+static void *subpage_init (target_phys_addr_t base, ram_addr_t *phys,
+                           ram_addr_t orig_memory)
 {
     subpage_t *mmio;
     int subpage_memory;
diff --git a/hw/an5206.c b/hw/an5206.c
index 320b3f7..8dd4db3 100644
--- a/hw/an5206.c
+++ b/hw/an5206.c
@@ -30,7 +30,7 @@
 
 /* Board init.  */
 
-static void an5206_init(int ram_size, int vga_ram_size,
+static void an5206_init(ram_addr_t ram_size, int vga_ram_size,
                      const char *boot_device, DisplayState *ds,
                      const char *kernel_filename, const char *kernel_cmdline,
                      const char *initrd_filename, const char *cpu_model)
diff --git a/hw/boards.h b/hw/boards.h
index d0f2e67..7fb2df5 100644
--- a/hw/boards.h
+++ b/hw/boards.h
@@ -3,7 +3,7 @@
 #ifndef HW_BOARDS_H
 #define HW_BOARDS_H
 
-typedef void QEMUMachineInitFunc(int ram_size, int vga_ram_size,
+typedef void QEMUMachineInitFunc(ram_addr_t ram_size, int vga_ram_size,
                                  const char *boot_device, DisplayState *ds,
                                  const char *kernel_filename,
                                  const char *kernel_cmdline,
diff --git a/hw/dummy_m68k.c b/hw/dummy_m68k.c
index 705d304..1641d56 100644
--- a/hw/dummy_m68k.c
+++ b/hw/dummy_m68k.c
@@ -14,7 +14,7 @@
 
 /* Board init.  */
 
-static void dummy_m68k_init(int ram_size, int vga_ram_size,
+static void dummy_m68k_init(ram_addr_t ram_size, int vga_ram_size,
                      const char *boot_device, DisplayState *ds,
                      const char *kernel_filename, const char *kernel_cmdline,
                      const char *initrd_filename, const char *cpu_model)
diff --git a/hw/etraxfs.c b/hw/etraxfs.c
index d3b9249..eb16258 100644
--- a/hw/etraxfs.c
+++ b/hw/etraxfs.c
@@ -41,7 +41,7 @@
 void etraxfs_ser_init(CPUState *env, qemu_irq *irqs, target_phys_addr_t base);
 
 static
-void bareetraxfs_init (int ram_size, int vga_ram_size,
+void bareetraxfs_init (ram_addr_t ram_size, int vga_ram_size,
                        const char *boot_device, DisplayState *ds,
                        const char *kernel_filename, const char *kernel_cmdline,
                        const char *initrd_filename, const char *cpu_model)
diff --git a/hw/gumstix.c b/hw/gumstix.c
index 55425e1..89bf684 100644
--- a/hw/gumstix.c
+++ b/hw/gumstix.c
@@ -41,7 +41,7 @@
 
 static const int sector_len = 128 * 1024;
 
-static void connex_init(int ram_size, int vga_ram_size,
+static void connex_init(ram_addr_t ram_size, int vga_ram_size,
                 const char *boot_device, DisplayState *ds,
                 const char *kernel_filename, const char *kernel_cmdline,
                 const char *initrd_filename, const char *cpu_model)
@@ -81,7 +81,7 @@
                     pxa2xx_gpio_in_get(cpu->gpio)[36]);
 }
 
-static void verdex_init(int ram_size, int vga_ram_size,
+static void verdex_init(ram_addr_t ram_size, int vga_ram_size,
                 const char *boot_device, DisplayState *ds,
                 const char *kernel_filename, const char *kernel_cmdline,
                 const char *initrd_filename, const char *cpu_model)
diff --git a/hw/integratorcp.c b/hw/integratorcp.c
index 8a75754..104796c 100644
--- a/hw/integratorcp.c
+++ b/hw/integratorcp.c
@@ -474,7 +474,7 @@
     .board_id = 0x113,
 };
 
-static void integratorcp_init(int ram_size, int vga_ram_size,
+static void integratorcp_init(ram_addr_t ram_size, int vga_ram_size,
                      const char *boot_device, DisplayState *ds,
                      const char *kernel_filename, const char *kernel_cmdline,
                      const char *initrd_filename, const char *cpu_model)
diff --git a/hw/mainstone.c b/hw/mainstone.c
index 1a87680..3de25d8 100644
--- a/hw/mainstone.c
+++ b/hw/mainstone.c
@@ -68,7 +68,7 @@
     .ram_size = 0x04000000,
 };
 
-static void mainstone_common_init(int ram_size, int vga_ram_size,
+static void mainstone_common_init(ram_addr_t ram_size, int vga_ram_size,
                 DisplayState *ds, const char *kernel_filename,
                 const char *kernel_cmdline, const char *initrd_filename,
                 const char *cpu_model, enum mainstone_model_e model, int arm_id)
@@ -134,7 +134,7 @@
     arm_load_kernel(cpu->env, &mainstone_binfo);
 }
 
-static void mainstone_init(int ram_size, int vga_ram_size,
+static void mainstone_init(ram_addr_t ram_size, int vga_ram_size,
                 const char *boot_device, DisplayState *ds,
                 const char *kernel_filename, const char *kernel_cmdline,
                 const char *initrd_filename, const char *cpu_model)
diff --git a/hw/mcf5208.c b/hw/mcf5208.c
index fd9c8aa..dfb504b 100644
--- a/hw/mcf5208.c
+++ b/hw/mcf5208.c
@@ -202,7 +202,7 @@
     }
 }
 
-static void mcf5208evb_init(int ram_size, int vga_ram_size,
+static void mcf5208evb_init(ram_addr_t ram_size, int vga_ram_size,
                      const char *boot_device, DisplayState *ds,
                      const char *kernel_filename, const char *kernel_cmdline,
                      const char *initrd_filename, const char *cpu_model)
diff --git a/hw/mips_jazz.c b/hw/mips_jazz.c
index e5e5baf..2fa2421 100644
--- a/hw/mips_jazz.c
+++ b/hw/mips_jazz.c
@@ -116,7 +116,7 @@
 #define MAGNUM_BIOS_SIZE (BIOS_SIZE < MAGNUM_BIOS_SIZE_MAX ? BIOS_SIZE : MAGNUM_BIOS_SIZE_MAX)
 
 static
-void mips_jazz_init (int ram_size, int vga_ram_size,
+void mips_jazz_init (ram_addr_t ram_size, int vga_ram_size,
                      DisplayState *ds, const char *cpu_model,
                      enum jazz_model_e jazz_model)
 {
@@ -256,7 +256,7 @@
 }
 
 static
-void mips_magnum_init (int ram_size, int vga_ram_size,
+void mips_magnum_init (ram_addr_t ram_size, int vga_ram_size,
                        const char *boot_device, DisplayState *ds,
                        const char *kernel_filename, const char *kernel_cmdline,
                        const char *initrd_filename, const char *cpu_model)
@@ -265,7 +265,7 @@
 }
 
 static
-void mips_pica61_init (int ram_size, int vga_ram_size,
+void mips_pica61_init (ram_addr_t ram_size, int vga_ram_size,
                        const char *boot_device, DisplayState *ds,
                        const char *kernel_filename, const char *kernel_cmdline,
                        const char *initrd_filename, const char *cpu_model)
diff --git a/hw/mips_malta.c b/hw/mips_malta.c
index 69b16b7..6c77f5f 100644
--- a/hw/mips_malta.c
+++ b/hw/mips_malta.c
@@ -763,7 +763,7 @@
 }
 
 static
-void mips_malta_init (int ram_size, int vga_ram_size,
+void mips_malta_init (ram_addr_t ram_size, int vga_ram_size,
                       const char *boot_device, DisplayState *ds,
                       const char *kernel_filename, const char *kernel_cmdline,
                       const char *initrd_filename, const char *cpu_model)
diff --git a/hw/mips_mipssim.c b/hw/mips_mipssim.c
index fac23be..a36ea67 100644
--- a/hw/mips_mipssim.c
+++ b/hw/mips_mipssim.c
@@ -106,7 +106,7 @@
 }
 
 static void
-mips_mipssim_init (int ram_size, int vga_ram_size,
+mips_mipssim_init (ram_addr_t ram_size, int vga_ram_size,
                    const char *boot_device, DisplayState *ds,
                    const char *kernel_filename, const char *kernel_cmdline,
                    const char *initrd_filename, const char *cpu_model)
diff --git a/hw/mips_r4k.c b/hw/mips_r4k.c
index fcebd47..09fe170 100644
--- a/hw/mips_r4k.c
+++ b/hw/mips_r4k.c
@@ -147,7 +147,7 @@
 
 static const int sector_len = 32 * 1024;
 static
-void mips_r4k_init (int ram_size, int vga_ram_size,
+void mips_r4k_init (ram_addr_t ram_size, int vga_ram_size,
                     const char *boot_device, DisplayState *ds,
                     const char *kernel_filename, const char *kernel_cmdline,
                     const char *initrd_filename, const char *cpu_model)
diff --git a/hw/nseries.c b/hw/nseries.c
index f6f69a0..be4ed2c 100644
--- a/hw/nseries.c
+++ b/hw/nseries.c
@@ -891,7 +891,7 @@
     .atag_board = n800_atag_setup,
 };
 
-static void n800_init(int ram_size, int vga_ram_size,
+static void n800_init(ram_addr_t ram_size, int vga_ram_size,
                 const char *boot_device, DisplayState *ds,
                 const char *kernel_filename, const char *kernel_cmdline,
                 const char *initrd_filename, const char *cpu_model)
diff --git a/hw/palm.c b/hw/palm.c
index 9969c71..a573ed7 100644
--- a/hw/palm.c
+++ b/hw/palm.c
@@ -200,7 +200,7 @@
     .board_id = 0x331,
 };
 
-static void palmte_init(int ram_size, int vga_ram_size,
+static void palmte_init(ram_addr_t ram_size, int vga_ram_size,
                 const char *boot_device, DisplayState *ds,
                 const char *kernel_filename, const char *kernel_cmdline,
                 const char *initrd_filename, const char *cpu_model)
diff --git a/hw/pc.c b/hw/pc.c
index d1db2a5..5d5a764 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -190,7 +190,8 @@
 }
 
 /* hd_table must contain 4 block drivers */
-static void cmos_init(int ram_size, const char *boot_device, BlockDriverState **hd_table)
+static void cmos_init(ram_addr_t ram_size, ram_addr_t above_4g_mem_size,
+                      const char *boot_device, BlockDriverState **hd_table)
 {
     RTCState *s = rtc_state;
     int nbds, bds[3] = { 0, };
@@ -213,6 +214,12 @@
     rtc_set_memory(s, 0x30, val);
     rtc_set_memory(s, 0x31, val >> 8);
 
+    if (above_4g_mem_size) {
+        rtc_set_memory(s, 0x5b, (unsigned int)above_4g_mem_size >> 16);
+        rtc_set_memory(s, 0x5c, (unsigned int)above_4g_mem_size >> 24);
+        rtc_set_memory(s, 0x5d, (uint64_t)above_4g_mem_size >> 32);
+    }
+
     if (ram_size > (16 * 1024 * 1024))
         val = (ram_size / 65536) - ((16 * 1024 * 1024) / 65536);
     else
@@ -678,7 +685,7 @@
 }
 
 /* PC hardware initialisation */
-static void pc_init1(int ram_size, int vga_ram_size,
+static void pc_init1(ram_addr_t ram_size, int vga_ram_size,
                      const char *boot_device, DisplayState *ds,
                      const char *kernel_filename, const char *kernel_cmdline,
                      const char *initrd_filename,
@@ -687,6 +694,7 @@
     char buf[1024];
     int ret, linux_boot, i;
     ram_addr_t ram_addr, vga_ram_addr, bios_offset, vga_bios_offset;
+    ram_addr_t below_4g_mem_size, above_4g_mem_size = 0;
     int bios_size, isa_bios_size, vga_bios_size;
     PCIBus *pci_bus;
     int piix3_devfn = -1;
@@ -698,6 +706,13 @@
     BlockDriverState *hd[MAX_IDE_BUS * MAX_IDE_DEVS];
     BlockDriverState *fd[MAX_FD];
 
+    if (ram_size >= 0xe0000000 ) {
+        above_4g_mem_size = ram_size - 0xe0000000;
+        below_4g_mem_size = 0xe0000000;
+    } else {
+        below_4g_mem_size = ram_size;
+    }
+
     linux_boot = (kernel_filename != NULL);
 
     /* init CPUs */
@@ -732,7 +747,13 @@
 
     /* allocate RAM */
     ram_addr = qemu_ram_alloc(ram_size);
-    cpu_register_physical_memory(0, ram_size, ram_addr);
+    cpu_register_physical_memory(0, below_4g_mem_size, ram_addr);
+
+    /* above 4giga memory allocation */
+    if (above_4g_mem_size > 0) {
+        cpu_register_physical_memory(0x100000000ULL, above_4g_mem_size,
+                                     ram_addr + below_4g_mem_size);
+    }
 
     /* allocate VGA RAM */
     vga_ram_addr = qemu_ram_alloc(vga_ram_size);
@@ -952,7 +973,7 @@
     }
     floppy_controller = fdctrl_init(i8259[6], 2, 0, 0x3f0, fd);
 
-    cmos_init(ram_size, boot_device, hd);
+    cmos_init(below_4g_mem_size, above_4g_mem_size, boot_device, hd);
 
     if (pci_enabled && usb_enabled) {
         usb_uhci_piix3_init(pci_bus, piix3_devfn + 2);
@@ -992,7 +1013,7 @@
     }
 }
 
-static void pc_init_pci(int ram_size, int vga_ram_size,
+static void pc_init_pci(ram_addr_t ram_size, int vga_ram_size,
                         const char *boot_device, DisplayState *ds,
                         const char *kernel_filename,
                         const char *kernel_cmdline,
@@ -1004,7 +1025,7 @@
              initrd_filename, 1, cpu_model);
 }
 
-static void pc_init_isa(int ram_size, int vga_ram_size,
+static void pc_init_isa(ram_addr_t ram_size, int vga_ram_size,
                         const char *boot_device, DisplayState *ds,
                         const char *kernel_filename,
                         const char *kernel_cmdline,
diff --git a/hw/piix_pci.c b/hw/piix_pci.c
index e1b6881..90cb3a6 100644
--- a/hw/piix_pci.c
+++ b/hw/piix_pci.c
@@ -55,7 +55,7 @@
     return (irq_num + slot_addend) & 3;
 }
 
-static uint32_t isa_page_descs[384 / 4];
+static target_phys_addr_t isa_page_descs[384 / 4];
 static uint8_t smm_enabled;
 static int pci_irq_levels[4];
 
diff --git a/hw/ppc405_boards.c b/hw/ppc405_boards.c
index 9ed2995..3e3ea56 100644
--- a/hw/ppc405_boards.c
+++ b/hw/ppc405_boards.c
@@ -177,7 +177,7 @@
     }
 }
 
-static void ref405ep_init (int ram_size, int vga_ram_size,
+static void ref405ep_init (ram_addr_t ram_size, int vga_ram_size,
                            const char *boot_device, DisplayState *ds,
                            const char *kernel_filename,
                            const char *kernel_cmdline,
@@ -505,7 +505,7 @@
     }
 }
 
-static void taihu_405ep_init(int ram_size, int vga_ram_size,
+static void taihu_405ep_init(ram_addr_t ram_size, int vga_ram_size,
                              const char *boot_device, DisplayState *ds,
                              const char *kernel_filename,
                              const char *kernel_cmdline,
diff --git a/hw/ppc_chrp.c b/hw/ppc_chrp.c
index c74dfd4..6511842 100644
--- a/hw/ppc_chrp.c
+++ b/hw/ppc_chrp.c
@@ -57,7 +57,7 @@
 };
 
 /* PowerPC Mac99 hardware initialisation */
-static void ppc_core99_init (int ram_size, int vga_ram_size,
+static void ppc_core99_init (ram_addr_t ram_size, int vga_ram_size,
                              const char *boot_device, DisplayState *ds,
                              const char *kernel_filename,
                              const char *kernel_cmdline,
diff --git a/hw/ppc_oldworld.c b/hw/ppc_oldworld.c
index a85524c..3ec5e86 100644
--- a/hw/ppc_oldworld.c
+++ b/hw/ppc_oldworld.c
@@ -103,7 +103,7 @@
     return 1; /* osi_call handled */
 }
 
-static void ppc_heathrow_init (int ram_size, int vga_ram_size,
+static void ppc_heathrow_init (ram_addr_t ram_size, int vga_ram_size,
                                const char *boot_device, DisplayState *ds,
                                const char *kernel_filename,
                                const char *kernel_cmdline,
diff --git a/hw/ppc_prep.c b/hw/ppc_prep.c
index 63ef15a..aaf4410 100644
--- a/hw/ppc_prep.c
+++ b/hw/ppc_prep.c
@@ -535,7 +535,7 @@
 #define NVRAM_SIZE        0x2000
 
 /* PowerPC PREP hardware initialisation */
-static void ppc_prep_init (int ram_size, int vga_ram_size,
+static void ppc_prep_init (ram_addr_t ram_size, int vga_ram_size,
                            const char *boot_device, DisplayState *ds,
                            const char *kernel_filename,
                            const char *kernel_cmdline,
diff --git a/hw/r2d.c b/hw/r2d.c
index 8480cf3..2294874 100644
--- a/hw/r2d.c
+++ b/hw/r2d.c
@@ -30,7 +30,7 @@
 #define SDRAM_BASE 0x0c000000 /* Physical location of SDRAM: Area 3 */
 #define SDRAM_SIZE 0x04000000
 
-static void r2d_init(int ram_size, int vga_ram_size,
+static void r2d_init(ram_addr_t ram_size, int vga_ram_size,
               const char *boot_device, DisplayState * ds,
 	      const char *kernel_filename, const char *kernel_cmdline,
 	      const char *initrd_filename, const char *cpu_model)
diff --git a/hw/realview.c b/hw/realview.c
index c3b26fa..16aa62b 100644
--- a/hw/realview.c
+++ b/hw/realview.c
@@ -23,7 +23,7 @@
     .board_id = 0x33b,
 };
 
-static void realview_init(int ram_size, int vga_ram_size,
+static void realview_init(ram_addr_t ram_size, int vga_ram_size,
                      const char *boot_device, DisplayState *ds,
                      const char *kernel_filename, const char *kernel_cmdline,
                      const char *initrd_filename, const char *cpu_model)
diff --git a/hw/shix.c b/hw/shix.c
index 5f8b2e1..eb75f0c 100644
--- a/hw/shix.c
+++ b/hw/shix.c
@@ -65,7 +65,7 @@
     /* XXXXX */
 }
 
-static void shix_init(int ram_size, int vga_ram_size,
+static void shix_init(ram_addr_t ram_size, int vga_ram_size,
                const char *boot_device, DisplayState * ds,
 	       const char *kernel_filename, const char *kernel_cmdline,
 	       const char *initrd_filename, const char *cpu_model)
diff --git a/hw/spitz.c b/hw/spitz.c
index 28987a6..82f8312 100644
--- a/hw/spitz.c
+++ b/hw/spitz.c
@@ -1188,7 +1188,7 @@
     .ram_size = 0x04000000,
 };
 
-static void spitz_common_init(int ram_size, int vga_ram_size,
+static void spitz_common_init(ram_addr_t ram_size, int vga_ram_size,
                 DisplayState *ds, const char *kernel_filename,
                 const char *kernel_cmdline, const char *initrd_filename,
                 const char *cpu_model, enum spitz_model_e model, int arm_id)
@@ -1246,7 +1246,7 @@
     sl_bootparam_write(SL_PXA_PARAM_BASE - PXA2XX_SDRAM_BASE);
 }
 
-static void spitz_init(int ram_size, int vga_ram_size,
+static void spitz_init(ram_addr_t ram_size, int vga_ram_size,
                 const char *boot_device, DisplayState *ds,
                 const char *kernel_filename, const char *kernel_cmdline,
                 const char *initrd_filename, const char *cpu_model)
@@ -1255,7 +1255,7 @@
                 kernel_cmdline, initrd_filename, cpu_model, spitz, 0x2c9);
 }
 
-static void borzoi_init(int ram_size, int vga_ram_size,
+static void borzoi_init(ram_addr_t ram_size, int vga_ram_size,
                 const char *boot_device, DisplayState *ds,
                 const char *kernel_filename, const char *kernel_cmdline,
                 const char *initrd_filename, const char *cpu_model)
@@ -1264,7 +1264,7 @@
                 kernel_cmdline, initrd_filename, cpu_model, borzoi, 0x33f);
 }
 
-static void akita_init(int ram_size, int vga_ram_size,
+static void akita_init(ram_addr_t ram_size, int vga_ram_size,
                 const char *boot_device, DisplayState *ds,
                 const char *kernel_filename, const char *kernel_cmdline,
                 const char *initrd_filename, const char *cpu_model)
@@ -1273,7 +1273,7 @@
                 kernel_cmdline, initrd_filename, cpu_model, akita, 0x2e8);
 }
 
-static void terrier_init(int ram_size, int vga_ram_size,
+static void terrier_init(ram_addr_t ram_size, int vga_ram_size,
                 const char *boot_device, DisplayState *ds,
                 const char *kernel_filename, const char *kernel_cmdline,
                 const char *initrd_filename, const char *cpu_model)
diff --git a/hw/stellaris.c b/hw/stellaris.c
index abd3416..a32f86f 100644
--- a/hw/stellaris.c
+++ b/hw/stellaris.c
@@ -1169,7 +1169,7 @@
 }
 
 /* FIXME: Figure out how to generate these from stellaris_boards.  */
-static void lm3s811evb_init(int ram_size, int vga_ram_size,
+static void lm3s811evb_init(ram_addr_t ram_size, int vga_ram_size,
                      const char *boot_device, DisplayState *ds,
                      const char *kernel_filename, const char *kernel_cmdline,
                      const char *initrd_filename, const char *cpu_model)
@@ -1177,7 +1177,7 @@
     stellaris_init(kernel_filename, cpu_model, ds, &stellaris_boards[0]);
 }
 
-static void lm3s6965evb_init(int ram_size, int vga_ram_size,
+static void lm3s6965evb_init(ram_addr_t ram_size, int vga_ram_size,
                      const char *boot_device, DisplayState *ds,
                      const char *kernel_filename, const char *kernel_cmdline,
                      const char *initrd_filename, const char *cpu_model)
diff --git a/hw/sun4m.c b/hw/sun4m.c
index dceb8d0..4d5720a 100644
--- a/hw/sun4m.c
+++ b/hw/sun4m.c
@@ -1113,7 +1113,7 @@
 };
 
 /* SPARCstation 5 hardware initialisation */
-static void ss5_init(int RAM_size, int vga_ram_size,
+static void ss5_init(ram_addr_t RAM_size, int vga_ram_size,
                      const char *boot_device, DisplayState *ds,
                      const char *kernel_filename, const char *kernel_cmdline,
                      const char *initrd_filename, const char *cpu_model)
@@ -1123,7 +1123,7 @@
 }
 
 /* SPARCstation 10 hardware initialisation */
-static void ss10_init(int RAM_size, int vga_ram_size,
+static void ss10_init(ram_addr_t RAM_size, int vga_ram_size,
                       const char *boot_device, DisplayState *ds,
                       const char *kernel_filename, const char *kernel_cmdline,
                       const char *initrd_filename, const char *cpu_model)
@@ -1133,7 +1133,7 @@
 }
 
 /* SPARCserver 600MP hardware initialisation */
-static void ss600mp_init(int RAM_size, int vga_ram_size,
+static void ss600mp_init(ram_addr_t RAM_size, int vga_ram_size,
                          const char *boot_device, DisplayState *ds,
                          const char *kernel_filename, const char *kernel_cmdline,
                          const char *initrd_filename, const char *cpu_model)
@@ -1143,7 +1143,7 @@
 }
 
 /* SPARCstation 20 hardware initialisation */
-static void ss20_init(int RAM_size, int vga_ram_size,
+static void ss20_init(ram_addr_t RAM_size, int vga_ram_size,
                       const char *boot_device, DisplayState *ds,
                       const char *kernel_filename, const char *kernel_cmdline,
                       const char *initrd_filename, const char *cpu_model)
@@ -1153,7 +1153,7 @@
 }
 
 /* SPARCstation 2 hardware initialisation */
-static void ss2_init(int RAM_size, int vga_ram_size,
+static void ss2_init(ram_addr_t RAM_size, int vga_ram_size,
                      const char *boot_device, DisplayState *ds,
                      const char *kernel_filename, const char *kernel_cmdline,
                      const char *initrd_filename, const char *cpu_model)
@@ -1493,7 +1493,7 @@
 }
 
 /* SPARCserver 1000 hardware initialisation */
-static void ss1000_init(int RAM_size, int vga_ram_size,
+static void ss1000_init(ram_addr_t RAM_size, int vga_ram_size,
                         const char *boot_device, DisplayState *ds,
                         const char *kernel_filename, const char *kernel_cmdline,
                         const char *initrd_filename, const char *cpu_model)
@@ -1503,7 +1503,7 @@
 }
 
 /* SPARCcenter 2000 hardware initialisation */
-static void ss2000_init(int RAM_size, int vga_ram_size,
+static void ss2000_init(ram_addr_t RAM_size, int vga_ram_size,
                         const char *boot_device, DisplayState *ds,
                         const char *kernel_filename, const char *kernel_cmdline,
                         const char *initrd_filename, const char *cpu_model)
diff --git a/hw/sun4u.c b/hw/sun4u.c
index b5f3ea4..68df48d 100644
--- a/hw/sun4u.c
+++ b/hw/sun4u.c
@@ -227,7 +227,7 @@
 static fdctrl_t *floppy_controller;
 
 /* Sun4u hardware initialisation */
-static void sun4u_init(int ram_size, int vga_ram_size,
+static void sun4u_init(ram_addr_t ram_size, int vga_ram_size,
                        const char *boot_devices, DisplayState *ds,
                        const char *kernel_filename, const char *kernel_cmdline,
                        const char *initrd_filename, const char *cpu_model)
diff --git a/hw/versatilepb.c b/hw/versatilepb.c
index ecc0037..1825f91 100644
--- a/hw/versatilepb.c
+++ b/hw/versatilepb.c
@@ -159,7 +159,7 @@
 
 static struct arm_boot_info versatile_binfo;
 
-static void versatile_init(int ram_size, int vga_ram_size,
+static void versatile_init(ram_addr_t ram_size, int vga_ram_size,
                      const char *boot_device, DisplayState *ds,
                      const char *kernel_filename, const char *kernel_cmdline,
                      const char *initrd_filename, const char *cpu_model,
@@ -293,7 +293,7 @@
     arm_load_kernel(env, &versatile_binfo);
 }
 
-static void vpb_init(int ram_size, int vga_ram_size,
+static void vpb_init(ram_addr_t ram_size, int vga_ram_size,
                      const char *boot_device, DisplayState *ds,
                      const char *kernel_filename, const char *kernel_cmdline,
                      const char *initrd_filename, const char *cpu_model)
@@ -304,7 +304,7 @@
                    initrd_filename, cpu_model, 0x183);
 }
 
-static void vab_init(int ram_size, int vga_ram_size,
+static void vab_init(ram_addr_t ram_size, int vga_ram_size,
                      const char *boot_device, DisplayState *ds,
                      const char *kernel_filename, const char *kernel_cmdline,
                      const char *initrd_filename, const char *cpu_model)
diff --git a/osdep.c b/osdep.c
index ae7e3fb..46434af 100644
--- a/osdep.c
+++ b/osdep.c
@@ -98,7 +98,6 @@
             int64_t free_space;
             int ram_mb;
 
-            extern int ram_size;
             free_space = (int64_t)stfs.f_bavail * stfs.f_bsize;
             if ((ram_size + 8192 * 1024) >= free_space) {
                 ram_mb = (ram_size / (1024 * 1024));
diff --git a/qemu-doc.texi b/qemu-doc.texi
index 68630c0..45c89ce 100644
--- a/qemu-doc.texi
+++ b/qemu-doc.texi
@@ -322,7 +322,9 @@
 be needed to boot from old floppy disks.
 
 @item -m @var{megs}
-Set virtual RAM size to @var{megs} megabytes. Default is 128 MiB.
+Set virtual RAM size to @var{megs} megabytes. Default is 128 MiB.  Optionally,
+a suffix of ``M'' or ``G'' can be used to signify a value in megabytes or
+gigabytes respectively.
 
 @item -smp @var{n}
 Simulate an SMP system with @var{n} CPUs. On the PC target, up to 255
diff --git a/sysemu.h b/sysemu.h
index 30bf966..9b4480f 100644
--- a/sysemu.h
+++ b/sysemu.h
@@ -73,7 +73,6 @@
 /* SLIRP */
 void do_info_slirp(void);
 
-extern int ram_size;
 extern int bios_size;
 extern int cirrus_vga_enabled;
 extern int vmsvga_enabled;
diff --git a/target-i386/helper.c b/target-i386/helper.c
index b2c8299..c3d307e 100644
--- a/target-i386/helper.c
+++ b/target-i386/helper.c
@@ -1747,7 +1747,21 @@
         break;
     case 0x80000008:
         /* virtual & phys address size in low 2 bytes. */
-        EAX = 0x00003028;
+/* XXX: This value must match the one used in the MMU code. */ 
+#if defined(TARGET_X86_64)
+#  if defined(USE_KQEMU)
+        EAX = 0x00003020;	/* 48 bits virtual, 32 bits physical */
+#  else
+/* XXX: The physical address space is limited to 42 bits in exec.c. */
+        EAX = 0x00003028;	/* 48 bits virtual, 40 bits physical */
+#  endif
+#else
+# if defined(USE_KQEMU)
+        EAX = 0x00000020;	/* 32 bits physical */
+#  else
+        EAX = 0x00000024;	/* 36 bits physical */
+#  endif
+#endif
         EBX = 0;
         ECX = 0;
         EDX = 0;
diff --git a/target-i386/helper2.c b/target-i386/helper2.c
index 106720a..6cf218f 100644
--- a/target-i386/helper2.c
+++ b/target-i386/helper2.c
@@ -800,8 +800,17 @@
 
 #else
 
-/* Bits 52-62 of a PTE are reserved. Bit 63 is the NX bit. */
-#define PHYS_ADDR_MASK 0xffffffffff000L
+/* XXX: This value should match the one returned by CPUID
+ * and in exec.c */
+#if defined(USE_KQEMU)
+#define PHYS_ADDR_MASK 0xfffff000L
+#else
+# if defined(TARGET_X86_64)
+# define PHYS_ADDR_MASK 0xfffffff000L
+# else
+# define PHYS_ADDR_MASK 0xffffff000L
+# endif
+#endif
 
 /* return value:
    -1 = cannot handle fault
diff --git a/vl.c b/vl.c
index 232072b..2b6e459 100644
--- a/vl.c
+++ b/vl.c
@@ -142,8 +142,6 @@
 //#define DEBUG_UNUSED_IOPORT
 //#define DEBUG_IOPORT
 
-#define PHYS_RAM_MAX_SIZE (2047 * 1024 * 1024)
-
 #ifdef TARGET_PPC
 #define DEFAULT_RAM_SIZE 144
 #else
@@ -175,7 +173,7 @@
 int curses;
 const char* keyboard_layout = NULL;
 int64_t ticks_per_sec;
-int ram_size;
+ram_addr_t ram_size;
 int pit_min_timer_count = 0;
 int nb_nics;
 NICInfo nd_table[MAX_NICS];
@@ -6877,7 +6875,8 @@
 
 static int ram_load_v1(QEMUFile *f, void *opaque)
 {
-    int i, ret;
+    int ret;
+    ram_addr_t i;
 
     if (qemu_get_be32(f) != phys_ram_size)
         return -EINVAL;
@@ -7013,7 +7012,7 @@
 
 static void ram_save(QEMUFile *f, void *opaque)
 {
-    int i;
+    ram_addr_t i;
     RamCompressState s1, *s = &s1;
     uint8_t buf[10];
 
@@ -7058,7 +7057,7 @@
 {
     RamDecompressState s1, *s = &s1;
     uint8_t buf[10];
-    int i;
+    ram_addr_t i;
 
     if (version_id == 1)
         return ram_load_v1(f, opaque);
@@ -7075,7 +7074,7 @@
         }
         if (buf[0] == 0) {
             if (ram_decompress_buf(s, phys_ram_base + i, BDRV_HASH_BLOCK_SIZE) < 0) {
-                fprintf(stderr, "Error while reading ram block address=0x%08x", i);
+                fprintf(stderr, "Error while reading ram block address=0x%08" PRIx64, (uint64_t)i);
                 goto error;
             }
         } else
@@ -8557,16 +8556,39 @@
             case QEMU_OPTION_h:
                 help(0);
                 break;
-            case QEMU_OPTION_m:
-                ram_size = atoi(optarg) * 1024 * 1024;
-                if (ram_size <= 0)
-                    help(1);
-                if (ram_size > PHYS_RAM_MAX_SIZE) {
-                    fprintf(stderr, "qemu: at most %d MB RAM can be simulated\n",
-                            PHYS_RAM_MAX_SIZE / (1024 * 1024));
+            case QEMU_OPTION_m: {
+                uint64_t value;
+                char *ptr;
+
+                value = strtoul(optarg, &ptr, 10);
+                switch (*ptr) {
+                case 0: case 'M': case 'm':
+                    value <<= 20;
+                    break;
+                case 'G': case 'g':
+                    value <<= 30;
+                    break;
+                default:
+                    fprintf(stderr, "qemu: invalid ram size: %s\n", optarg);
                     exit(1);
                 }
+
+                /* On 32-bit hosts, QEMU is limited by virtual address space */
+                if (value > (2047 << 20)
+#ifndef USE_KQEMU
+                    && HOST_LONG_BITS == 32
+#endif
+                    ) {
+                    fprintf(stderr, "qemu: at most 2047 MB RAM can be simulated\n");
+                    exit(1);
+                }
+                if (value != (uint64_t)(ram_addr_t)value) {
+                    fprintf(stderr, "qemu: ram size too large\n");
+                    exit(1);
+                }
+                ram_size = value;
                 break;
+            }
             case QEMU_OPTION_d:
                 {
                     int mask;