On 7/15/25 6:21 PM, Paolo Abeni wrote:
> On 7/15/25 9:42 AM, Akihiko Odaki wrote:
>> On 2025/07/11 22:02, Paolo Abeni wrote:
>>> @@ -158,7 +159,10 @@ struct VirtIOPCIProxy {
>>> uint32_t nvectors;
>>> uint32_t dfselect;
>>> uint32_t gfselect;
>>> - uint32_t guest_features[2];
>>> + union {
>>> + uint32_t guest_features[2];
>>> + uint32_t guest_features128[4];
>>> + };
>>
>> I don't see anything preventing you from directly extending guest_features.
>
> Uhmm... I have a vague memory of some interim revisions doing that and
> failing miserably (but I have no log of the actual details). I'll try to
> have another shot at it.
The VMSTATE_ARRAY() macro has explicit checks on the specified array
matching exactly the specified array size. Using a single:
uint32_t guest_features[4];
variable, this statement
VMSTATE_UINT32_ARRAY(guest_features, VirtIOPCIProxy, 2),
causes the following build error:
--
include/migration/vmstate.h:259:48: error: invalid operands to binary -
(have ‘uint32_t (*)[2]’ {aka ‘unsigned int (*)[2]’} and ‘uint32_t
(*)[4]’ {aka ‘unsigned int (*)[4]’})
259 | #define type_check_array(t1,t2,n) ((t1(*)[n])0 - (t2*)0)
| ^
include/migration/vmstate.h:282:6: note: in expansion of macro
‘type_check_array’
282 | type_check_array(_type, typeof_field(_state, _field), _num))
| ^~~~~~~~~~~~~~~~
include/migration/vmstate.h:373:19: note: in expansion of macro
‘vmstate_offset_array’
373 | .offset = vmstate_offset_array(_state, _field, _type,
_num), \
| ^~~~~~~~~~~~~~~~~~~~
include/migration/vmstate.h:1090:5: note: in expansion of macro
‘VMSTATE_ARRAY’
1090 | VMSTATE_ARRAY(_f, _s, _n, _v, vmstate_info_uint32, uint32_t)
| ^~~~~~~~~~~~~
include/migration/vmstate.h:1096:5: note: in expansion of macro
‘VMSTATE_UINT32_ARRAY_V’
1096 | VMSTATE_UINT32_ARRAY_V(_f, _s, _n, 0)
| ^~~~~~~~~~~~~~~~~~~~~~
../hw/virtio/virtio-pci.c:168:9: note: in expansion of macro
‘VMSTATE_UINT32_ARRAY’
168 | VMSTATE_UINT32_ARRAY(guest_features, VirtIOPCIProxy, 2),
| ^~~~~~~~~~~~~~~~~~~~
--
I'll keep the union here.
Thanks,
Paolo
