Re: [Qemu-devel] best way to implement a "memclear" type instruction in TCG?

[Peter Maydell]

On 22 January 2014 19:24, Xin Tong <address@hidden> wrote:
> would there be any memory ordering issue ? what if the host processor
> has a more relaxed memory ordering then the guest. maybe memset with
> membarriers in between.

In general we can ignore memory ordering issues because for
system emulation every TCG guest CPU runs in a single host
thread. (For linux-user emulation with a multithreaded guest binary
we just shrug and hope, but multithreaded guest programs don't work
for all sorts of other reasons...)

For AArch64 in particular this instruction works on Normal memory
and so the CPU is at liberty to perform fairly aggressive reordering
anyway.

thanks
-- PMM