[Qemu-devel] [PATCH v1 1/3] cputlb: ensure tbl_set_dirty1 updates addr_write atomically

["Alex Bennée" <alex.bennee@linaro.org>]

This was an oversight when the rest of cputlb was being updated. As
before it falls back to the non-atomic version when the host can't
support wider-than-bus atomics.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
---
 cputlb.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/cputlb.c b/cputlb.c
index f5d056cc08..0d52e45dfd 100644
--- a/cputlb.c
+++ b/cputlb.c
@@ -540,9 +540,17 @@ void tlb_reset_dirty(CPUState *cpu, ram_addr_t start1, ram_addr_t length)
 
 static inline void tlb_set_dirty1(CPUTLBEntry *tlb_entry, target_ulong vaddr)
 {
+#if TCG_OVERSIZED_GUEST
     if (tlb_entry->addr_write == (vaddr | TLB_NOTDIRTY)) {
         tlb_entry->addr_write = vaddr;
     }
+#else
+    uintptr_t orig_addr = atomic_mb_read(&tlb_entry->addr_write);
+
+    if (orig_addr == (vaddr | TLB_NOTDIRTY)) {
+        atomic_cmpxchg(&tlb_entry->addr_write, orig_addr, vaddr);
+    }
+#endif
 }
 
 /* update the TLB corresponding to virtual page vaddr
-- 
2.11.0