Re: [Xen-devel] Help on domain creation

[Steven Hand <Steven.Hand@xxxxxxxxxxxx>]

>I did run it as root on domain0. The program calls ioctl(,SNDCTL...) and
>denied access. ??????  What does it do with sound device? The error
>returned for xi_phys_grant is "invalid argument".

The ioctl numbers used by xenctl etc are not in the standard linux
namespace; and so are not understood by strace.  We should probably 
fix this at some point. 
 
>Any ideas?

>open("/proc/xeno/privcmd", O_RDWR)      = 3
>ioctl(3, SNDCTL_DSP_RESET, 0xbffff4e0)  = -1 EPERM (Operation not
>permitted)
>write(2, "ERROR: Error when executing priv"..., 83ERROR: Error when
>executing privileged control ioctl (1 = Operation not permitted)
>) = 83

I believe that SNDCTL_DSP_RESET is actually '0' and hence corresponds
to a hypercall being made by the user tools in domain 0. 

The fact that you get 'EPERM' is kinda odd; this should only really
be the case if the calling domain (guest OS) is not privileged -- but
domain 0 is always privileged. 

The second one is also odd; the ioctl(SNDCTL_DISP_SYNC) is '1' afaics 
and hence corresponds to a block device control message; this will 
return EINVAL if e.g. the buffer size being used is larger than a page
size but xi_phys_grant shouldn't cause this. Can't currently see how 
else this cane be triggered. 

Hmm; will try to sort this out once back from trip, 

S.