[Qemu-devel] [RFC v8 05/14] softmmu: Add new TLB_EXCL flag

[Alvise Rigo <a.rigo@virtualopensystems.com>]

Add a new TLB flag to force all the accesses made to a page to follow
the slow-path.

The TLB entries referring guest pages with the DIRTY_MEMORY_EXCLUSIVE
bit clean will have this flag set.

Suggested-by: Jani Kokkonen <jani.kokkonen@huawei.com>
Suggested-by: Claudio Fontana <claudio.fontana@huawei.com>
Signed-off-by: Alvise Rigo <a.rigo@virtualopensystems.com>
---
 include/exec/cpu-all.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h
index 83b1781..f8d8feb 100644
--- a/include/exec/cpu-all.h
+++ b/include/exec/cpu-all.h
@@ -277,6 +277,14 @@ CPUArchState *cpu_copy(CPUArchState *env);
 #define TLB_NOTDIRTY    (1 << 4)
 /* Set if TLB entry is an IO callback.  */
 #define TLB_MMIO        (1 << 5)
+/* Set if TLB entry references a page that requires exclusive access.  */
+#define TLB_EXCL        (1 << 6)
+
+/* Do not allow a TARGET_PAGE_MASK which covers one or more bits defined
+ * above. */
+#if TLB_EXCL >= TARGET_PAGE_SIZE
+#error TARGET_PAGE_MASK covering the low bits of the TLB virtual address
+#endif
 
 void dump_exec_info(FILE *f, fprintf_function cpu_fprintf);
 void dump_opcount_info(FILE *f, fprintf_function cpu_fprintf);
-- 
2.8.0