[Qemu-devel] [PATCH v3 18/29] translate-all: make less of tb_invalidate_phys_page_range depend on is_cpu_write_access

[Paolo Bonzini <pbonzini@redhat.com>]

is_cpu_write_access is only set if tb_invalidate_phys_page_range is called
from tb_invalidate_phys_page_fast, and hence from notdirty_mem_write.
However:

- the code bitmap can be built directly in tb_invalidate_phys_page_fast
  (unconditionally, since is_cpu_write_access would always be passed as 1);

- the virtual address is not needed to mark the page as "not containing
  code" (dirty code bitmap = 1), so we can also remove that use of
  is_cpu_write_access.  For calls of tb_invalidate_phys_page_range
  that do not come from notdirty_mem_write, the next call to
  notdirty_mem_write will notice that the page does not contain code
  anymore, and will fix up the TLB entry.

The parameter needs to remain in order to guard accesses to cpu->mem_io_pc.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 translate-all.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/translate-all.c b/translate-all.c
index 0e2ad8a..e2e7422 100644
--- a/translate-all.c
+++ b/translate-all.c
@@ -1082,12 +1082,6 @@ void tb_invalidate_phys_page_range(tb_page_addr_t start, tb_page_addr_t end,
     if (!p) {
         return;
     }
-    if (!p->code_bitmap &&
-        ++p->code_write_count >= SMC_BITMAP_USE_THRESHOLD &&
-        is_cpu_write_access) {
-        /* build code bitmap */
-        build_page_bitmap(p);
-    }
 #if defined(TARGET_HAS_PRECISE_SMC)
     if (cpu != NULL) {
         env = cpu->env_ptr;
@@ -1157,9 +1151,7 @@ void tb_invalidate_phys_page_range(tb_page_addr_t start, tb_page_addr_t end,
     /* if no code remaining, no need to continue to use slow writes */
     if (!p->first_tb) {
         invalidate_page_bitmap(p);
-        if (is_cpu_write_access) {
-            tlb_unprotect_code(start);
-        }
+        tlb_unprotect_code(start);
     }
 #endif
 #ifdef TARGET_HAS_PRECISE_SMC
@@ -1192,6 +1184,11 @@ void tb_invalidate_phys_page_fast(tb_page_addr_t start, int len)
     if (!p) {
         return;
     }
+    if (!p->code_bitmap &&
+        ++p->code_write_count >= SMC_BITMAP_USE_THRESHOLD) {
+        /* build code bitmap */
+        build_page_bitmap(p);
+    }
     if (p->code_bitmap) {
         unsigned int nr;
         unsigned long b;
-- 
1.8.3.1