[PATCH 4/6] qemu-kvm: Introduce cpu_physical_memory_get_dirty_range().

Yoshiaki Tamura
2010-03-16T10:56:21Z

Introduces cpu_physical_memory_get_dirty_range().
It checks the first row and puts dirty addr in the array.
If the first row is empty, it skips to the first non-dirty row
or the end addr, and put the length in the first entry of the array.

Signed-off-by: Yoshiaki Tamura <tamura.yoshiaki@lab.ntt.co.jp>
Signed-off-by: OHMURA Kei <ohmura.kei@lab.ntt.co.jp>
---
exec.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 73 insertions(+), 0 deletions(-)

diff --git a/exec.c b/exec.c
index b31c349..87056a6 100644
--- a/exec.c
+++ b/exec.c
@@ -1961,6 +1961,79 @@ static inline void tlb_reset_dirty_range(CPUTLBEntry *tlb_entry,
}
}

+/* It checks the first row and puts dirty addrs in the array.
+ If the first row is empty, it skips to the first non-dirty row
+ or the end addr, and put the length in the first entry of the array. */
+int cpu_physical_memory_get_dirty_range(ram_addr_t start, ram_addr_t end,
+ ram_addr_t *dirty_rams, int length,
+ int dirty_flag)
+{
+ unsigned long phys_ram_dirty, page_number, *p;
+ ram_addr_t addr;
+ int s_idx = (start >> TARGET_PAGE_BITS) / HOST_LONG_BITS;
+ int e_idx = (end >> TARGET_PAGE_BITS) / HOST_LONG_BITS;
+ int i, j, offset;
+
+ switch (dirty_flag) {
+ case VGA_DIRTY_FLAG:
+ p = phys_ram_vga_dirty;
+ break;
+ case CODE_DIRTY_FLAG:
+ p = phys_ram_code_dirty;
+ break;
+ case MIGRATION_DIRTY_FLAG:
+ p = phys_ram_migration_dirty;
+ break;
+ default:
+ abort();
+ }
+
+ /* mask bits before the start addr */
+ offset = (start >> TARGET_PAGE_BITS) & (HOST_LONG_BITS - 1);
+ phys_ram_dirty = p[s_idx] & ~((1UL << offset) - 1);
+
+ if (s_idx == e_idx) {
+ /* mask bits after the end addr */
+ offset = (end >> TARGET_PAGE_BITS) & (HOST_LONG_BITS - 1);
+ phys_ram_dirty &= (1UL << offset) - 1;
+ }
+
+ if (phys_ram_dirty == 0) {
+ /* when the row is empty */
+ ram_addr_t skip;
+ if (s_idx == e_idx)
+ skip = end;
+ else {
+ /* skip empty rows */
+ while (s_idx < e_idx && p[++s_idx] == 0);
+ skip = (s_idx * HOST_LONG_BITS * TARGET_PAGE_SIZE);
+ }
+ dirty_rams[0] = skip - start;
+ i = 0;
+
+ } else if (phys_ram_dirty == ~0UL) {
+ /* when the row is fully dirtied */
+ addr = start;
+ for (i = 0; i < length; i++) {
+ dirty_rams[i] = addr;
+ addr += TARGET_PAGE_SIZE;
+ }
+ } else {
+ /* when the row is partially dirtied */
+ i = 0;
+ do {
+ j = ffsl(phys_ram_dirty) - 1;
+ phys_ram_dirty &= ~(1UL << j);
+ page_number = s_idx * HOST_LONG_BITS + j;
+ addr = page_number * TARGET_PAGE_SIZE;
+ dirty_rams[i] = addr;
+ i++;
+ } while (phys_ram_dirty != 0 && i < length);
+ }
+
+ return i;
+}
+
/* Note: start and end must be within the same ram block. */
void cpu_physical_memory_reset_dirty(ram_addr_t start, ram_addr_t end,
int dirty_flags)
--
1.7.0.31.g1df487