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From: Paolo Bonzini <pbonzini@redhat.com>
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Date: Tue, 2 Feb 2016 15:25:50 +0100
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Subject: Re: [Qemu-devel] [PULL 14/49] scripts/kvm/kvm_stat: Improve debugfs
 access checking
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To: Christian Borntraeger <borntraeger@de.ibm.com>, qemu-devel@nongnu.org
Cc: Janosch Frank <frankja@linux.vnet.ibm.com>



On 02/02/2016 15:02, Christian Borntraeger wrote:
>> > -if not os.access('/sys/kernel/debug', os.F_OK):
>> > -    print 'Please enable CONFIG_DEBUG_FS in your kernel'
>> > +if not os.path.exists('/sys/kernel/debug'):
>> > +    sys.stderr.write('Please enable CONFIG_DEBUG_FS in your kernel.')
>> >      sys.exit(1)
>> > -if not os.access(PATH_DEBUGFS_KVM, os.F_OK):
>> > -    print "Please mount debugfs ('mount -t debugfs debugfs /sys/kernel/debug')"
>> > -    print "and ensure the kvm modules are loaded"
>> > +if not os.path.exists(PATH_DEBUGFS_KVM):
>> > +    sys.stderr.write("Please make sure, that debugfs is mounted and "
>> > +                     "readable by the current user:\n"
>> > +                     "('mount -t debugfs debugfs /sys/kernel/debug')\n"
>> > +                     "Also ensure, that the kvm modules are loaded.\n")
>> > +    sys.exit(1)
>> > +if not os.path.exists(PATH_DEBUGFS_TRACING):
>> > +    sys.stderr.write("Please make {0} readable by the current user.\n"
>> > +                     .format(PATH_DEBUGFS_TRACING))
>> >      sys.exit(1)
> 
> Hmmm, this now bails out on kernels without CONFIG_TRACING. It could still fall
> back to the normal kvm_stat values. What about just removing the last sys.exit(1)
> and make this a warning that stays for a second or so?

Good idea.  Can you send a patch?

Paolo