@@ -53,6 +53,7 @@ void qemu_ram_set_idstr(ram_addr_t addr, const char *name, DeviceState *dev);
void cpu_physical_memory_rw(target_phys_addr_t addr, uint8_t *buf,
int len, int is_write);
+void cpu_physical_memory_zero(target_phys_addr_t addr, int len);
static inline void cpu_physical_memory_read(target_phys_addr_t addr,
void *buf, int len)
{
@@ -3639,6 +3639,62 @@ void cpu_physical_memory_rw(target_phys_addr_t addr, uint8_t *buf,
}
}
+void cpu_physical_memory_zero(target_phys_addr_t addr, int len)
+{
+ int l, io_index;
+ uint8_t *ptr;
+ target_phys_addr_t page;
+ ram_addr_t pd;
+ PhysPageDesc p;
+
+ while (len > 0) {
+ page = addr & TARGET_PAGE_MASK;
+ l = (page + TARGET_PAGE_SIZE) - addr;
+ if (l > len) {
+ l = len;
+ }
+ p = phys_page_find(page >> TARGET_PAGE_BITS);
+ pd = p.phys_offset;
+
+ if ((pd & ~TARGET_PAGE_MASK) != io_mem_ram.ram_addr) {
+ target_phys_addr_t addr1;
+ io_index = pd & (IO_MEM_NB_ENTRIES - 1);
+ addr1 = (addr & ~TARGET_PAGE_MASK) + p.region_offset;
+ /* XXX: could force cpu_single_env to NULL to avoid
+ potential bugs */
+ if (l >= 4 && ((addr1 & 3) == 0)) {
+ /* 32 bit write access */
+ io_mem_write(io_index, addr1, 0, 4);
+ l = 4;
+ } else if (l >= 2 && ((addr1 & 1) == 0)) {
+ /* 16 bit write access */
+ io_mem_write(io_index, addr1, 0, 2);
+ l = 2;
+ } else {
+ /* 8 bit write access */
+ io_mem_write(io_index, addr1, 0, 1);
+ l = 1;
+ }
+ } else {
+ ram_addr_t addr1;
+ addr1 = (pd & TARGET_PAGE_MASK) + (addr & ~TARGET_PAGE_MASK);
+ /* RAM case */
+ ptr = qemu_get_ram_ptr(addr1);
+ memset(ptr, 0, l);
+ if (!cpu_physical_memory_is_dirty(addr1)) {
+ /* invalidate code */
+ tb_invalidate_phys_page_range(addr1, addr1 + l, 0);
+ /* set dirty bit */
+ cpu_physical_memory_set_dirty_flags(
+ addr1, (0xff & ~CODE_DIRTY_FLAG));
+ }
+ qemu_put_ram_ptr(ptr);
+ }
+ len -= l;
+ addr += l;
+ }
+}
+
/* used for ROM loading : can write in RAM and ROM */
void cpu_physical_memory_write_rom(target_phys_addr_t addr,
const uint8_t *buf, int len)
This patch adds cpu_physical_memory_zero() function. This is equivalent to calling cpu_physical_memory_write() with a buffer full of zeroes, but avoids actually allocating such a buffer along the way. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> --- cpu-common.h | 1 + exec.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 57 insertions(+), 0 deletions(-)