On Wed, Dec 09, 2015 at 09:32:49AM -0500, Boris Ostrovsky wrote: > Adding the rtc platform device in a Xen PV guests causes an IRQ > conflict because these guests do not have a legacy PIC. > > In a single VCPU Xen PV guest we should have: > > /proc/interrupts: > CPU0 > 0: 4934 xen-percpu-virq timer0 > 1: 0 xen-percpu-ipi spinlock0 > 2: 0 xen-percpu-ipi resched0 > 3: 0 xen-percpu-ipi callfunc0 > 4: 0 xen-percpu-virq debug0 > 5: 0 xen-percpu-ipi callfuncsingle0 > 6: 0 xen-percpu-ipi irqwork0 > 7: 321 xen-dyn-event xenbus > 8: 90 xen-dyn-event hvc_console > ... > > But hvc_console cannot get its interrupt because it is already in use > by rtc0 and the console does not work. > > genirq: Flags mismatch irq 8. 00000000 (hvc_console) vs. 00000000 (rtc0) > > So don't add the rtc_cmos device in Xen PV guests. (In fact, don't add > it to any paravirt_enabled() guest since lguest is also unable to probe > this device) > > Reported-by: Sander Eikelenboom <li...@eikelenboom.it> > Signed-off-by: David Vrabel <david.vra...@citrix.com> > Signed-off-by: Boris Ostrovsky <boris.ostrov...@oracle.com> > Tested-by: Sander Eikelenboom <li...@eikelenboom.it> > Cc: sta...@vger.kernel.org
Reviewed-by: Konrad Rzeszutek Wilk <konrad.w...@oracle.com> You may want to also add a note saying: [stable-tree maintainers. Please double-check that you also have 29fa6825463c97e5157284db80107d1bfac5d77b x86, kvm: Clear paravirt_enabled on KVM guests for espfix32's benefit which sets pv_info.paravirt_enabled to zero.] > --- > arch/x86/kernel/rtc.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c > index cd96852..dd4d6d9 100644 > --- a/arch/x86/kernel/rtc.c > +++ b/arch/x86/kernel/rtc.c > @@ -200,6 +200,9 @@ static __init int add_rtc_cmos(void) > } > #endif > > + if (paravirt_enabled()) > + return -ENODEV; > + > platform_device_register(&rtc_device); > dev_info(&rtc_device.dev, > "registered platform RTC device (no PNP device found)\n"); > -- > 1.8.1.4 > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
