Re: [PATCH v3 08/39] xen/riscv: implement virtual APLIC MMIO emulation

[Jan Beulich <jbeulich@xxxxxxxx>]

On 13.10.2026 18:06, Oleksii Kurochko wrote:
> On 10/5/26 4:53 PM, Baptiste Le Duc wrote:
>>> Guests running under Xen program interrupt routing by writing to APLIC
>>> MMIO registers. Xen must intercept these accesses to enforce interrupt
>>> isolation between domains and to translate guest routing intent into the
>>> underlying physical MSI topology.
>>>
>>> Register the vAPLIC range with the MMIO dispatch and emulate the accesses:
>>>   - reads and writes are masked with the domain's authorised interrupt
>>>     bitmap, so that a guest can neither observe nor affect interrupts it
>>>     does not own;
>>>   - target registers are shadowed per source, so that a guest reads back
>>>     what it wrote. The h/w register instead gets the hart index and guest
>>>     interrupt file of the pCPU the target vCPU's interrupt file lives on,
>>>     as the APLIC uses these fields directly to compute the MSI address. As
>>>     long as the target vCPU has no h/w guest interrupt file, only the
>>>     shadow copy is updated;
>>>   - only MSI delivery mode is emulated: target writes made while the
>>>     guest's domaincfg.DM is clear are ignored.
>>>
>>> Delegation (APLIC_SOURCECFG_D) is not yet supported.
>>>
>>> Co-developed-by: Romain Caritey <Romain.Caritey@xxxxxxxxxxxxx>
>>> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
>> Co-developed-by: needs a matching Signed-off-by: from Romain right after
>> it.
> 
> I will contact Romain and ask for his Signed-off-by.

Just to mention: Co-developed-by: can mean many things. We haven't been
insisting on matching S-o-b before. Plus if there was an S-o-b, why
would there want/need to be Co-developed-by: as well?

Jan