[libvirt] [PATCH v2] Add a virt-host-validate command to sanity check HV config

[Daniel P. Berrange]

On Fri, Jan 27, 2012 at 09:54:27AM -0700, Eric Blake wrote:
> On 01/27/2012 07:59 AM, Daniel P. Berrange wrote:

> > +int virHostValidateDevice(const char *hvname,
> > +                          const char *devname,
> > +                          virHostValidateLevel level,
> > +                          const char *hint)
> > +{
> > +    virHostMsgCheck(hvname, "for device %s", devname);
> > +
> > +    if (access(devname, R_OK|W_OK) < 0) {
> > +        virHostMsgFail(level, hint);
> 
> This could have different failures, depending on whether it is called as
> root or as an ordinary user; should we be trying to refine things if
> /dev/kvm exists with 600 permissions but the current euid can't
> read/write it?

True, but I wanted to keep life simple for now.

> 
> > +int virHostValidateHasCPUFlag(const char *name)
> > +{
> > +    FILE *fp = fopen("/proc/cpuinfo", "r");
> > +    int ret = 0;
> 
> You're using this like a bool, so maybe s/int/bool/ and s/0/false/ make
> sense.

Yes, good idea.

> 
> > +
> > +    if (virParseVersionString(uts.release, &thisversion, true) < 0) {
> > +        virHostMsgFail(level, hint);
> > +        return -1;
> > +    }
> > +
> > +    micro = (thisversion & 0xff);
> > +    minor = ((thisversion >> 8) & 0xff);
> > +    major = ((thisversion >> 16) & 0xff);
> > +
> > +    if (major > ((version >> 16) & 0xff)) {
> > +        virHostMsgPass();
> > +        return 0;
> > +    } else if (major < ((version >> 16) & 0xff)) {
> > +        virHostMsgFail(level, hint);
> > +        return -1;
> > +    }
> 
> Rather than break things down and check major/minor/micro independently,
> why not just check if thisversion >= version and get all three checks
> done at once?

Hmm, yes that does work

> > +
> > +int virHostValidateQEMU(void)
> > +{
> > +    int ret = 0;
> > +
> > +    if (virHostValidateHasCPUFlag("svm") ||
> > +        virHostValidateHasCPUFlag("vmx")) {
> > +        if (virHostValidateDevice("QEMU", "/dev/kvm",
> > +                                  VIR_HOST_VALIDATE_FAIL,
> > +                                  _("Check that the 'kvm-intel' or 'kvm-amd' modules are "
> > +                                    "loaded & the BIOS has enabled virtualization")) < 0)
> > +            ret = -1;
> > +    }
> 
> Should we have an else clause with VIR_HOST_VALIDATE_WARN that hardware
> lacks virtualization, therefore guests will run slower, when this is run
> on older cpus?

I added in an explicit message about hardware virt

> > +
> > +#if WITH_QEMU
> > +    if ((!hvname || STREQ(hvname, "qemu")) &&
> > +        virHostValidateQEMU() < 0)
> > +        ret = EXIT_FAILURE;
> > +#endif
> 
> Needs:
> 
> #else
>     if (STREQ(hvname, "qemu"))
>         fail; this libvirt was not compiled with qemu support
> 
> > +
> > +#if WITH_LXC
> > +    if ((!hvname || STREQ(hvname, "lxc")) &&
> > +        virHostValidateLXC() < 0)
> > +        ret = EXIT_FAILURE;
> > +#endif
> 
> A similar #else complaining about no lxc support.

I did this a little differently so we can catch all unsupported
hvname strings


Daniel
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