Hi Jan,
On 24/03/2025 12:05, Jan Beulich wrote:
> On 24.03.2025 10:00, Oleksii Moisieiev wrote:
>> Hi Jan,
>>
>> Let me answer one of your comment. Please see below:
>>
>> On 11/03/2025 13:43, Jan Beulich wrote:
>>> On 11.03.2025 12:16, Grygorii Strashko wrote:
>>>> --- a/MAINTAINERS
>>>> +++ b/MAINTAINERS
>>>> @@ -526,6 +526,12 @@ S: Supported
>>>> F: xen/arch/arm/include/asm/tee/
>> [snip]
>>>> --- a/xen/include/public/arch-arm.h
>>>> +++ b/xen/include/public/arch-arm.h
>>>> @@ -327,6 +327,8 @@ DEFINE_XEN_GUEST_HANDLE(vcpu_guest_context_t);
>>>> #define XEN_DOMCTL_CONFIG_TEE_OPTEE 1
>>>> #define XEN_DOMCTL_CONFIG_TEE_FFA 2
>>>>
>>>> +#define XEN_DOMCTL_CONFIG_ARM_SCI_NONE 0
>>>> +
>>>> struct xen_arch_domainconfig {
>>>> /* IN/OUT */
>>>> uint8_t gic_version;
>>>> @@ -350,6 +352,8 @@ struct xen_arch_domainconfig {
>>>> *
>>>> */
>>>> uint32_t clock_frequency;
>>>> + /* IN */
>>>> + uint8_t arm_sci_type;
>>>> };
>>> You're not re-using a pre-existing padding field, so I don't see how you
>>> can get away without bumping XEN_DOMCTL_INTERFACE_VERSION.
>> We are reusing an existing padding field in xen_domctl, which is defined
>> as pad[128].
>>
>> The xen_arch_domainconfig structure is a part of the following domctl
>> structures:
>>
>> - xen_domctl_createdomain
>>
>> - xen_domctl_getdomaininfo
>>
>> These structures are included in the union within xen_domctl, which
>> defines pad[128] for padding.
> Except that "an existing padding field" means a field which isn't just
> there in space, but is also checked to be zero right now. That is, new
> code setting the field to non-zero needs to properly get an error
> indicator back from an older hypervisor.
I completely agree with you that XEN_DOMCTL_INTERFACE_VERSION should be
incremented
before the changes are merged. I just wanted to point out that we do not
exceed the size of the xen_domctl padding. If you are okay with the
fields we have added, then XEN_DOMCTL_INTERFACE_VERSION will be updated
in the next patch series.
> but is also checked to be zero right now.
Just out of curiosity, I have one more question: I couldn't find the
check you've mentioned. Could you point me to where Xen or
the toolstack checks the domctl structure for 0? I would greatly
appreciate it if you could show me.
WBR,
Oleksii.
