Re: [Xen-devel] [v4][PATCH 04/19] xen/passthrough: extend hypercall to support rdm reservation policy

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 01.07.15 at 12:47, <tiejun.chen@xxxxxxxxx> wrote:
> On 2015/7/1 18:02, George Dunlap wrote:
>> On 07/01/2015 02:11 AM, Chen, Tiejun wrote:
>>> /* XEN_DOMCTL_createdomain */
>>> struct xen_domctl_createdomain {
>>>      /* IN parameters */
>>>      uint32_t ssidref;
>>>      xen_domain_handle_t handle;
>>>   /* Is this an HVM guest (as opposed to a PVH or PV guest)? */
>>> #define _XEN_DOMCTL_CDF_hvm_guest     0
>>> #define XEN_DOMCTL_CDF_hvm_guest      (1U<<_XEN_DOMCTL_CDF_hvm_guest)
>>>   /* Use hardware-assisted paging if available? */
>>> #define _XEN_DOMCTL_CDF_hap           1
>>> #define XEN_DOMCTL_CDF_hap            (1U<<_XEN_DOMCTL_CDF_hap)
>>>   /* Should domain memory integrity be verifed by tboot during Sx? */
>>> #define _XEN_DOMCTL_CDF_s3_integrity  2
>>> #define XEN_DOMCTL_CDF_s3_integrity   (1U<<_XEN_DOMCTL_CDF_s3_integrity)
>>>   /* Disable out-of-sync shadow page tables? */
>>> #define _XEN_DOMCTL_CDF_oos_off       3
>>> #define XEN_DOMCTL_CDF_oos_off        (1U<<_XEN_DOMCTL_CDF_oos_off)
>>>   /* Is this a PVH guest (as opposed to an HVM or PV guest)? */
>>> #define _XEN_DOMCTL_CDF_pvh_guest     4
>>> #define XEN_DOMCTL_CDF_pvh_guest      (1U<<_XEN_DOMCTL_CDF_pvh_guest)
>>>      uint32_t flags;
>>
>> Yes, this demonstrates my point.  Each of these is a single-bit boolean
>> value that takes up a single bit -- either on or off.  But here you have
>> three values -- NO_DRM, RELAXED, and STRICT, that take up two bits.  If
> 
> Is this fine to you?
> 
> #define _XEN_DOMCTL_DEV_NO_RDM          0
> #define XEN_DOMCTL_DEV_NO_RDM           (1U<<_XEN_DOMCTL_DEV_NO_RDM)
> #define _XEN_DOMCTL_DEV_RDM_RELAXED     1
> #define XEN_DOMCTL_DEV_RDM_RELAXED      (1U<<_XEN_DOMCTL_DEV_RDM_RELAXED)
> #define _XEN_DOMCTL_DEV_RDM_STRICT      2
> #define XEN_DOMCTL_DEV_RDM_STRICT       (1U<<_XEN_DOMCTL_DEV_RDM_STRICT)

AIUI these aren't individual flags, but kind of an enumeration. I.e.
you should keep the original definitions and add - as suggested by
George - a mask (two bits wide right now).

Jan


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