On 08/18/2011 08:13 PM, Peter Maydell wrote: > On 19 August 2011 03:59, 陳韋任 <che...@iis.sinica.edu.tw> wrote: >>> More generally and not x86-specific, there are problems with >>> the multithreaded user-mode support which I suspect exist because >>> nobody has ever sat down and worked out a coherent design for it, >>> including what might need to be thread-local and what locking >>> is required. So the result is that it mostly works but if you >> >> You mean some QEMU data structures need to be thread-local or lock >> protected in order to emulate guest multi-threaded program correctly? > > Approximately, yes (the third option being "redesign the data > structure so it can be sensibly protected"). See > https://bugs.launchpad.net/qemu/+bug/668799 for discussion of > one example.
I suspect that to make things tractable for i386, which has so many LOCKable instructions, that we'll also have to implement at least a compare-and-swap primitive in TCG. r~
