Re: [Qemu-devel] global_mutex and multithread.

[Paolo Bonzini]

On 15/01/2015 13:51, Frederic Konrad wrote:
> 
> 
> Thanks for the reply.
> 
> As I understand the idea of Jan is to unlock the global_mutex during tcg
> execution.
> Is that right?
> So that means it's currently not the case and we won't be able to run
> two TCG
> threads at the same time?

Yes.

> About the RCU, is there a lot of device which change the memory map?

All PCI devices (when you program their BARs), but apart from that not
much.  As a first approximation, the patches on github which use
CPU_INTERRUPT_TLBFLUSH should work even for multiple TCG threads.

I'll clean them up a bit further so that CPU_INTERRUPT_TLBFLUSH is used
for CPUs other than the running one; the running CPU instead uses
tlb_flush directly.

If anyone can sum up how cpu_resume_from_signal works, that would also
be helpful.

Paolo