Re: [PATCH v3 2/3] xen/riscv: add RISC-V legacy SBI extension support for guests

[Oleksii Kurochko <oleksii.kurochko@gmail.com>]

On 12/24/25 10:05 AM, Oleksii Kurochko wrote:
>
> On 12/23/25 5:11 PM, Jan Beulich wrote:
>> On 22.12.2025 17:37, Oleksii Kurochko wrote:
>>> +static int vsbi_legacy_ecall_handler(unsigned long eid, unsigned 
>>> long fid,
>>> +                                     struct cpu_user_regs *regs)
>>> +{
>>> +    int ret = 0;
>>> +
>>> +    switch ( eid )
>>> +    {
>>> +    case SBI_EXT_0_1_CONSOLE_PUTCHAR:
>>> +        vsbi_print_char(regs->a0);
>>> +        break;
>>> +
>>> +    case SBI_EXT_0_1_CONSOLE_GETCHAR:
>>> +        ret = SBI_ERR_NOT_SUPPORTED;
>>> +        break;
>>> +
>>> +    default:
>>> +        /*
>>> +         * TODO: domain_crash() is acceptable here while things are 
>>> still under
>>> +         * development.
>>> +         * It shouldn't stay like this in the end though: guests 
>>> should not
>>> +         * be punished like this for something Xen hasn't implemented.
>>> +         */
>>> +        domain_crash(current->domain,
>>> +                     "%s: Unsupported ecall: FID: #%lx, EID: #%lx\n",
>> Hmm, wait - patch 1 says you would consistently use #%lu for FIDs. I 
>> can adjust
>> while committing, unless you tell me not to.
>
> I think that we should drop printing FID at all for Legacy extension 
> as according to
> the spec.:
>   The SBI function ID field in a6 register is ignored because these 
> are encoded as multiple SBI
>   extension IDs.
> And according to "Function Listing" FID will be 0:
> https://github.com/riscv-non-isa/riscv-sbi-doc/blob/master/src/ext-legacy.adoc#function-listing
>
> I would be happy if you could drop printing of FID during commit. Let 
> me know if you want me to
> drop printing of FID in the next patch series version.
>
EID printing should be also updated to #%#lx.

Sorry for noticing that only now.

~ Oleksii