[PATCH v4 38/48] Documentation: KVM: Add docs for KVM_DEV_ARM_VGIC_GRP_IST

[Fuad Tabba]

Hi Sascha,

On Fri, 24 Jul 2026 at 11:59, Sascha Bischoff <Sascha.Bischoff at arm.com> wrote:
...
> +      -ENOENT      A userspace SPI IST buffer was supplied, but there is no SPI
> +                   IST to serialise/unserialise

I do not think -ENOENT can be returned. The branch producing it in
`vgic_v5_get_spi_ist_desc()` needs `!ist->base && userspace_buf`, but
`vgic_v5_validate_ist_attr()` runs first at both call sites and
rejects a zero `spi_ist_addr`, and a VGICv5 VM always has an SPI IST
by the time this attribute is reachable. That leaves the
`userspace_buf` argument without an effect either, so this may be a
code fix rather than a documentation one.

Cheers,
/fuad