Re: [PATCH v5 34/49] KVM: arm64: gic-v5: Add VGICv5 IST save/restore UAPI

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Incomplete implementation: UAPI definitions added without corresponding kernel backend
--

--- Patch [34]: [PATCH v5 34/49] KVM: arm64: gic-v5: Add VGICv5 IST save/restore UAPI ---
commit db4f69bf4672970c99891b1c1bd9652c4ebfb88a
Author: Sascha Bischoff <[email protected]>

KVM: arm64: gic-v5: Add VGICv5 IST save/restore UAPI
    
This commit introduces KVM_DEV_ARM_VGIC_GRP_IST as a VGICv5 device attribute
group to transfer SPI and LPI IST state between KVM and userspace. It defines
struct kvm_vgic_v5_ist as a descriptor for the IST buffers.

> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
> index 710a0d267347d..9998252ea8ec8 100644
> --- a/arch/arm64/include/uapi/asm/kvm.h
> +++ b/arch/arm64/include/uapi/asm/kvm.h
> @@ -423,6 +423,15 @@ enum {
>  #define KVM_DEV_ARM_VGIC_GRP_ITS_REGS 8
>  #define KVM_DEV_ARM_VGIC_GRP_MAINT_IRQ  9
>  #define KVM_DEV_ARM_VGIC_GRP_IRS_REGS	10
> +#define KVM_DEV_ARM_VGIC_GRP_IST	11
> +
> +struct kvm_vgic_v5_ist {
> +	__u64	spi_ist_addr;
> +	__u64	spi_ist_size;
> +	__u64	lpi_ist_addr;
> +	__u64	lpi_ist_size;
> +};

[Severity: Medium]
Are the backend ioctl handlers for this new UAPI missing from this patch?

The commit message notes this is used to transfer state between KVM and
userspace, but it looks like only the header definitions are present.

Without the backend code, userspace attempting to use KVM_DEV_ARM_VGIC_GRP_IST
will receive an error.

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=34