Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests

Gabriel L. Somlo
2017-03-16T19:25:55Z

On Thu, Mar 16, 2017 at 08:29:32PM +0200, Michael S. Tsirkin wrote:
> Let's take a step back and try to figure out how is
> mwait called. How about dumping code of VCPUs
> around mwait? gdb disa command will do this.

Started guest with '-s', tried to attach from gdb with
"target remote localhost:1234", got
"remote 'g' packet reply is too long: <lengthy string of numbers>"

Tried typing 'cont' in the qemu monitor, got os x to crash:

panic (cpu 1 caller 0xffffff7f813ff488): pmLock: waited too long, held
by 0xffffff7f813eff65

Hmm, maybe that's where it keeps its monitor/mwait idle loop.
Restarted the guest, tried this from monitor:

dump-guest-memory foobar 0xffffff7f813e0000 0x20000

Got "'dump-guest-memory' has failed: integer is for 32-bit values"

Hmmm... I have no idea what I'm doing anymore at this point... :)

--G