Re: [Qemu-devel] [PATCH v3 2/4] timer: protect timers_state's clock with seqlock

[Alex Bligh]

On 27 Aug 2013, at 04:21, Liu Ping Fan wrote:

> Note in tcg mode, vm_clock still read inside BQL, so icount is

Should refer to QEMU_CLOCK_VIRTUAL if after my patches

> left without private lock's protection. As for cpu_ticks_* in
> timers_state, it is still protected by BQL.

I *think* what you are saying here is that after this patch,
reading QEMU_CLOCK_VIRTUAL is threadsafe unless use_icount
is true, in which case it is not thread safe as existing
callers rely on the BQL.

The commit could be a bit more specific here, not least as
if I read it right, that will need fixing before
QEMU_CLOCK_VIRTUAL is used at all in other other threads.

-- 
Alex Bligh