Re: [PATCH v2 4/4] tools/libs: Apply MSR policy to a guest

[Boris Ostrovsky <boris.ostrovsky@oracle.com>]

On 2/18/21 6:48 AM, Roger Pau Monné wrote:
>
>> +    /* Get the domain's default policy. */
>> +    nr_leaves = 0;
>> +    rc = xc_get_system_cpu_policy(xch, di.hvm ? XEN_SYSCTL_cpu_policy_hvm_default
>> +                                              : XEN_SYSCTL_cpu_policy_pv_default,
>> +                                  &nr_leaves, NULL, &nr_msrs, msrs);
>> +    if ( rc )
>> +    {
>> +        PERROR("Failed to obtain %s default policy", di.hvm ? "hvm" : "pv");
>> +        rc = -errno;
>> +        goto out;
>> +    }
> Why not use xc_get_domain_cpu_policy instead so that you can avoid the
> call to xc_domain_getinfo?


Yes, indeed.


-boris


>
> It would also seem safer, as you won't be discarding any adjustments
> made to the default policy by the hypervisor for this specific domain.
>
> Thanks, Roger.