On Tue, 15 Nov 2011, Anthony Liguori wrote: > On 11/15/2011 08:51 AM, stefano.stabell...@eu.citrix.com wrote: > > From: Stefano Stabellini<stefano.stabell...@eu.citrix.com> > > > > Xen doesn't need full RTC emulation in Qemu because the RTC is already > > emulated by the hypervisor. In particular we want to avoid the timers > > initialization so that Qemu doesn't need to wake up needlessly. > > > > Signed-off-by: Stefano Stabellini<stefano.stabell...@eu.citrix.com> > > Yuck. There's got to be a better way to do this.
Yeah, it is pretty ugly, I was hoping in some good suggestions to improve this patch :) > I think it would be better to name timers and then in Xen specific machine > code, > disable the RTC timers. Good idea! I was thinking that I could implement an rtc_stop function in mc146818rtc.c that stops and frees the timers. Now the problem is that from xen-all.c I cannot easily find the ISADevice instance to pass to rtc_stop. Do you think it would be reasonable to call rtc_stop from pc_basic_device_init, inside the same if (!xen_available()) introduce by the next patch? Otherwise I could implement functions to walk the isa bus, similarly to pci_for_each_device. This is just an example: diff --git a/hw/mc146818rtc.c b/hw/mc146818rtc.c index 2aaca2f..568c540 100644 --- a/hw/mc146818rtc.c +++ b/hw/mc146818rtc.c @@ -667,6 +667,28 @@ ISADevice *rtc_init(int base_year, qemu_irq intercept_irq) return dev; } +void rtc_stop(ISADevice *dev) +{ + RTCState *s = DO_UPCAST(RTCState, dev, dev); + + qemu_del_timer(s->periodic_timer); + qemu_del_timer(s->second_timer); + qemu_del_timer(s->second_timer2); +#ifdef TARGET_I386 + if (rtc_td_hack) { + qemu_del_timer(s->coalesced_timer); + } +#endif + qemu_free_timer(s->periodic_timer); + qemu_free_timer(s->second_timer); + qemu_free_timer(s->second_timer2); +#ifdef TARGET_I386 + if (rtc_td_hack) { + qemu_free_timer(s->coalesced_timer); + } +#endif +} + static ISADeviceInfo mc146818rtc_info = { .qdev.name = "mc146818rtc", .qdev.size = sizeof(RTCState), diff --git a/hw/mc146818rtc.h b/hw/mc146818rtc.h index 575968c..aa2b8ab 100644 --- a/hw/mc146818rtc.h +++ b/hw/mc146818rtc.h @@ -8,5 +8,6 @@ ISADevice *rtc_init(int base_year, qemu_irq intercept_irq); void rtc_set_memory(ISADevice *dev, int addr, int val); void rtc_set_date(ISADevice *dev, const struct tm *tm); +void rtc_stop(ISADevice *dev); #endif /* !MC146818RTC_H */ diff --git a/hw/pc.c b/hw/pc.c index a0ae981..d734f75 100644 --- a/hw/pc.c +++ b/hw/pc.c @@ -1145,6 +1145,8 @@ void pc_basic_device_init(qemu_irq *gsi, if (!xen_available()) { pit = pit_init(0x40, 0); + } else { + rtc_stop(*rtc_state); } pcspk_init(pit);