[Qemu-devel] Question: cpu_physical_memory_map() and atomic test and set bit pattern

[Andrey Smetanin]

Hello, QEMU Developers!

cpu_physical_memory_map() calls directly addess_space_map() which has 
comment "Use only for reads OR writes - not for read-modify-write 
operations."

Why there is such restriction (only read or write access) in 
addess_space_map()/cpu_physical_memory_map() ?
How to transparently atomically test and set bit of guest memory inside 
QEMU host?
Is there any API for that pattern ? Or may I use cpu_physical_memory_map 
with is_write = 1 for that safely ?


Thanks,
Andrey