aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorStefan Hajnoczi <stefanha@redhat.com>2014-12-02 11:23:18 +0000
committerPaolo Bonzini <pbonzini@redhat.com>2015-06-05 17:10:00 +0200
commit03eebc9e3246b9b3f5925aa41f7dfd7c1e467875 (patch)
tree74641e34056f1169770c48aa604477315210d6be
parent20015f72bda7d2f356c43580a5542a659afedf83 (diff)
memory: replace cpu_physical_memory_reset_dirty() with test-and-clear
The cpu_physical_memory_reset_dirty() function is sometimes used together with cpu_physical_memory_get_dirty(). This is not atomic since two separate accesses to the dirty memory bitmap are made. Turn cpu_physical_memory_reset_dirty() and cpu_physical_memory_clear_dirty_range_type() into the atomic cpu_physical_memory_test_and_clear_dirty(). Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <1417519399-3166-6-git-send-email-stefanha@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--cputlb.c4
-rw-r--r--exec.c23
-rw-r--r--include/exec/ram_addr.h33
-rw-r--r--memory.c11
4 files changed, 33 insertions, 38 deletions
diff --git a/cputlb.c b/cputlb.c
index dd1203b938..a50608676c 100644
--- a/cputlb.c
+++ b/cputlb.c
@@ -125,8 +125,8 @@ void tlb_flush_page(CPUState *cpu, target_ulong addr)
can be detected */
void tlb_protect_code(ram_addr_t ram_addr)
{
- cpu_physical_memory_reset_dirty(ram_addr, TARGET_PAGE_SIZE,
- DIRTY_MEMORY_CODE);
+ cpu_physical_memory_test_and_clear_dirty(ram_addr, TARGET_PAGE_SIZE,
+ DIRTY_MEMORY_CODE);
}
/* update the TLB so that writes in physical page 'phys_addr' are no longer
diff --git a/exec.c b/exec.c
index 162c57908e..487583b1bd 100644
--- a/exec.c
+++ b/exec.c
@@ -852,16 +852,27 @@ static void tlb_reset_dirty_range_all(ram_addr_t start, ram_addr_t length)
}
/* Note: start and end must be within the same ram block. */
-void cpu_physical_memory_reset_dirty(ram_addr_t start, ram_addr_t length,
- unsigned client)
+bool cpu_physical_memory_test_and_clear_dirty(ram_addr_t start,
+ ram_addr_t length,
+ unsigned client)
{
- if (length == 0)
- return;
- cpu_physical_memory_clear_dirty_range_type(start, length, client);
+ unsigned long end, page;
+ bool dirty;
- if (tcg_enabled()) {
+ if (length == 0) {
+ return false;
+ }
+
+ end = TARGET_PAGE_ALIGN(start + length) >> TARGET_PAGE_BITS;
+ page = start >> TARGET_PAGE_BITS;
+ dirty = bitmap_test_and_clear_atomic(ram_list.dirty_memory[client],
+ page, end - page);
+
+ if (dirty && tcg_enabled()) {
tlb_reset_dirty_range_all(start, length);
}
+
+ return dirty;
}
/* Called from RCU critical section */
diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
index 63db371850..a2beea7925 100644
--- a/include/exec/ram_addr.h
+++ b/include/exec/ram_addr.h
@@ -194,30 +194,19 @@ static inline void cpu_physical_memory_set_dirty_lebitmap(unsigned long *bitmap,
}
#endif /* not _WIN32 */
-static inline void cpu_physical_memory_clear_dirty_range_type(ram_addr_t start,
- ram_addr_t length,
- unsigned client)
-{
- unsigned long end, page;
-
- assert(client < DIRTY_MEMORY_NUM);
- end = TARGET_PAGE_ALIGN(start + length) >> TARGET_PAGE_BITS;
- page = start >> TARGET_PAGE_BITS;
- bitmap_clear(ram_list.dirty_memory[client], page, end - page);
-}
+bool cpu_physical_memory_test_and_clear_dirty(ram_addr_t start,
+ ram_addr_t length,
+ unsigned client);
static inline void cpu_physical_memory_clear_dirty_range(ram_addr_t start,
ram_addr_t length)
{
- cpu_physical_memory_clear_dirty_range_type(start, length, DIRTY_MEMORY_MIGRATION);
- cpu_physical_memory_clear_dirty_range_type(start, length, DIRTY_MEMORY_VGA);
- cpu_physical_memory_clear_dirty_range_type(start, length, DIRTY_MEMORY_CODE);
+ cpu_physical_memory_test_and_clear_dirty(start, length, DIRTY_MEMORY_MIGRATION);
+ cpu_physical_memory_test_and_clear_dirty(start, length, DIRTY_MEMORY_VGA);
+ cpu_physical_memory_test_and_clear_dirty(start, length, DIRTY_MEMORY_CODE);
}
-void cpu_physical_memory_reset_dirty(ram_addr_t start, ram_addr_t length,
- unsigned client);
-
static inline
uint64_t cpu_physical_memory_sync_dirty_bitmap(unsigned long *dest,
ram_addr_t start,
@@ -245,16 +234,14 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(unsigned long *dest,
}
} else {
for (addr = 0; addr < length; addr += TARGET_PAGE_SIZE) {
- if (cpu_physical_memory_get_dirty(start + addr,
- TARGET_PAGE_SIZE,
- DIRTY_MEMORY_MIGRATION)) {
+ if (cpu_physical_memory_test_and_clear_dirty(
+ start + addr,
+ TARGET_PAGE_SIZE,
+ DIRTY_MEMORY_MIGRATION)) {
long k = (start + addr) >> TARGET_PAGE_BITS;
if (!test_and_set_bit(k, dest)) {
num_dirty++;
}
- cpu_physical_memory_reset_dirty(start + addr,
- TARGET_PAGE_SIZE,
- DIRTY_MEMORY_MIGRATION);
}
}
}
diff --git a/memory.c b/memory.c
index 418cac7ce1..0c5d32807e 100644
--- a/memory.c
+++ b/memory.c
@@ -1468,13 +1468,9 @@ void memory_region_set_dirty(MemoryRegion *mr, hwaddr addr,
bool memory_region_test_and_clear_dirty(MemoryRegion *mr, hwaddr addr,
hwaddr size, unsigned client)
{
- bool ret;
assert(mr->terminates);
- ret = cpu_physical_memory_get_dirty(mr->ram_addr + addr, size, client);
- if (ret) {
- cpu_physical_memory_reset_dirty(mr->ram_addr + addr, size, client);
- }
- return ret;
+ return cpu_physical_memory_test_and_clear_dirty(mr->ram_addr + addr,
+ size, client);
}
@@ -1518,7 +1514,8 @@ void memory_region_reset_dirty(MemoryRegion *mr, hwaddr addr,
hwaddr size, unsigned client)
{
assert(mr->terminates);
- cpu_physical_memory_reset_dirty(mr->ram_addr + addr, size, client);
+ cpu_physical_memory_test_and_clear_dirty(mr->ram_addr + addr, size,
+ client);
}
int memory_region_get_fd(MemoryRegion *mr)