• Martin Schwidefsky's avatar
    s390/kvm: fix detection of guest machine checks · 0a5e2ec2
    Martin Schwidefsky authored
    The new detection code for guest machine checks added a check based
    on %r11 to .Lcleanup_sie to distinguish between normal asynchronous
    interrupts and machine checks. But the funtion is called from the
    program check handler as well with an undefined value in %r11.
    
    The effect is that all program exceptions pointing to the SIE instruction
    will set the CIF_MCCK_GUEST bit. The bit stays set for the CPU until the
     next machine check comes in which will incorrectly be interpreted as a
    guest machine check.
    
    The simplest fix is to stop using .Lcleanup_sie in the program check
    handler and duplicate a few instructions.
    
    Fixes: c929500d ("s390/nmi: s390: New low level handling for machine check happening in guest")
    Cc: <stable@vger.kernel.org> # v4.13+
    Reviewed-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
    Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
    0a5e2ec2
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