Re: [Xen-devel] [PATCH v9 04/11] public: xen.h: add definitions for UUID handling

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 11.10.17 at 01:24, <sstabellini@xxxxxxxxxx> wrote:
> On Tue, 10 Oct 2017, Volodymyr Babchuk wrote:
>> --- a/xen/include/public/xen.h
>> +++ b/xen/include/public/xen.h
>> @@ -930,6 +930,39 @@ __DEFINE_XEN_GUEST_HANDLE(uint16, uint16_t);
>>  __DEFINE_XEN_GUEST_HANDLE(uint32, uint32_t);
>>  __DEFINE_XEN_GUEST_HANDLE(uint64, uint64_t);
>>  
>> +typedef struct {
>> +    uint8_t a[16];
>> +} xen_uuid_t;
>> +
>> +/*
>> + * XEN_DEFINE_UUID(0x00112233, 0x4455, 0x6677, 0x8899,
>> + *                 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff)
>> + * will construct UUID 00112233-4455-6677-8899-aabbccddeeff presented as
>> + * {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88,
>> + * 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff};
>> + *
>> + * NB: This is compatible with Linux kernel and with libuuid, but it is not
>> + * compatible with Microsoft, as they use mixed-endian encoding (some
>> + * components are little-endian, some are big-endian).
>> + */
>> +#define XEN_DEFINE_UUID_(a, b, c, d, e1, e2, e3, e4, e5, e6)            \
>> +    {{((a) >> 24) & 0xFF, ((a) >> 16) & 0xFF,                           \
>> +      ((a) >>  8) & 0xFF, ((a) >>  0) & 0xFF,                           \
>> +      ((b) >>  8) & 0xFF, ((b) >>  0) & 0xFF,                           \
>> +      ((c) >>  8) & 0xFF, ((c) >>  0) & 0xFF,                           \
>> +      ((d) >>  8) & 0xFF, ((d) >>  0) & 0xFF,                           \
>> +                e1, e2, e3, e4, e5, e6}}
>> +
>> +/* Compound literals are supported in C99 and later. */
>> +#if defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L
>> +#define XEN_DEFINE_UUID(a, b, c, d, e1, e2, e3, e4, e5, e6)             \
>> +    ((xen_uuid_t)XEN_DEFINE_UUID_(a, b, c, d, e1, e2, e3, e4, e5, e6))
>> +#else
>> +#define XEN_DEFINE_UUID(a, b, c, d, e1, e2, e3, e4, e5, e6)             \
>> +    XEN_DEFINE_UUID_(a, b, c, d, e1, e2, e3, e4, e5, e6)
>> +
>> +#endif /* defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L */
>> +
>>  #endif /* !__ASSEMBLY__ */
>>  
>>  /* Default definitions for macros used by domctl/sysctl. */
> 
> This looks good to me, but I would like to get Jan's opinion on this.
> Ideally we would commit the series tomorrow before the code freeze.

While I can live with it being the way it is now, I've already
indicated that I'd prefer __GNUC__ to also be checked for
here. As that's a relaxation, it wouldn't be a problem to add
later, I think (but I can't exclude I'm overlooking something,
so it would feel better if it was done the intended final way
from the beginning).

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel