[Bug 221033] New: Real time clock does not trigger alarm on QEMU

[Bug 221033] New: Real time clock does not trigger alarm on QEMU

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=221033

            Bug ID: 221033
           Summary: Real time clock does not trigger alarm on QEMU
           Product: Virtualization
           Version: unspecified
          Hardware: i386
                OS: Linux
            Status: NEW
          Severity: low
          Priority: P3
         Component: kvm
          Assignee: virtualization_kvm@kernel-bugs.osdl.org
          Reporter: richard.lyu@suse.com
        Regression: No

LTP test rtc01.c [0] attempts to enable alarm via ioctl() RTC_AIE_ON on
/dev/rtc. Following select() timeouts (returns zero) instead of triggering
alarm. I would expect to fail with -1 or pass, timeout is strange:

./rtc01
rtc01       0  TINFO  :  RTC READ TEST:
rtc01       1  TPASS  :  RTC READ TEST Passed
rtc01       0  TINFO  :  Current RTC date/time is 14-11-2025, 01:35:18.
rtc01       0  TINFO  :  RTC ALARM TEST :
rtc01       0  TINFO  :  Alarm time set to 01:35:23.
rtc01       0  TINFO  :  Waiting 5 seconds for the alarm...
rtc01       2  TFAIL  :  rtc01.c:151: Timed out waiting for the alarm
rtc01       0  TINFO  :  RTC UPDATE INTERRUPTS TEST :
rtc01       0  TINFO  :  Waiting for  5 update interrupts...
rtc01       3  TFAIL  :  rtc01.c:208: Timed out waiting for the update
interrupt
rtc01       0  TINFO  :  RTC Tests Done!

The bug only triggers in a VM, not on bare metal. I'm not sure yet whether this
is a bug or expected behavior within a VM environment.

[0]
https://github.com/linux-test-project/ltp/tree/master/testcases/kernel/device-drivers/rtc

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[Bug 221033] Real time clock does not trigger alarm on QEMU

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=221033

Richard Lyu (richard.lyu@suse.com) changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Hardware|i386                        |IA-64

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[Bug 221033] Real time clock does not trigger alarm on QEMU

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=221033

Petr Vorel (petr.vorel@gmail.com) changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |petr.vorel@gmail.com

--- Comment #1 from Petr Vorel (petr.vorel@gmail.com) ---
Also, the problem is only when running VM on UEFI (legacy BIOS works).

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