Re: [PATCH v2 35/39] xen/riscv: add basic VGEIN management for AIA guests

[Jan Beulich <jbeulich@xxxxxxxx>]

On 27.08.2026 17:21, Oleksii Kurochko wrote:
> It was decided to add support for IMSIC from the start instead of having APLIC
> operate in direct delivery mode, as it requires a trap-and-emulation approach,
> which is not optimal from a performance standpoint.
> 
> AIA provides a hardware-accelerated mechanism for delivering external
> interrupts to domains via "guest interrupt files" located in IMSIC.
> A single physical hart can implement multiple such files (up to GEILEN),
> allowing several virtual harts to receive interrupts directly from hardware.
> 
> Introduce per-CPU tracking of guest interrupt file identifiers (VGEIN)
> for systems implementing AIA specification. Each CPU maintains
> a bitmap describing which guest interrupt files are currently in use.
> 
> Implement helpers to initialize the bitmap based on the number of available
> guest interrupt files (GEILEN), assign a VGEIN to a vCPU, and release it
> when no longer needed.
> 
> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>

Acked-by: Jan Beulich <jbeulich@xxxxxxxx>