> -----Original Message----- > From: Peter Maydell [mailto:peter.mayd...@linaro.org] > Sent: Tuesday, February 06, 2018 5:49 PM > To: Gonglei (Arei) > Cc: Paolo Bonzini; QEMU Developers; Huangweidong (C) > Subject: Re: [Qemu-devel] [PATCH] rtc: placing RTC memory region outside BQL > > On 6 February 2018 at 08:24, Gonglei (Arei) <arei.gong...@huawei.com> > wrote: > > So, taking BQL is necessary, and what we can do is trying our best to narrow > > down the process of locking ? For example, do the following wrapping: > > > > static void rtc_rasie_irq(RTCState *s) > > { > > qemu_mutex_lock_iothread(); > > qemu_irq_raise(s->irq); > > qemu_mutex_unlock_iothread(); > > } > > > > static void rtc_lower_irq(RTCState *s) > > { > > qemu_mutex_lock_iothread(); > > qemu_irq_lower(s->irq); > > qemu_mutex_unlock_iothread(); > > } > > If you do that you'll also need to be careful about not calling > those functions from contexts where you already hold the iothread > mutex (eg timer callbacks), since you can't lock a mutex you > already have locked. > Exactly, all contexts caused by the main process. :) Three timers callbacks, calling rtc_reset().
Thanks, -Gonglei
