Messages in this thread Patch in this message | | | From | Boris Ostrovsky <> | Subject | [PATCH] x86: Xen PV guests don't have the rtc_cmos platform device | Date | Wed, 9 Dec 2015 09:32:49 -0500 |
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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 <linux@eikelenboom.it> Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Tested-by: Sander Eikelenboom <linux@eikelenboom.it> Cc: stable@vger.kernel.org --- 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
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