Re: [RFC PATCH v4 03/11] coco: guest: arm64: Add Realm Host Interface and guest DA helper

[Kameron Carr <kameroncarr@linux.microsoft.com>]

On 4/27/2026 1:27 AM, Aneesh Kumar K.V (Arm) wrote:
> - Add  guest-side rhi-da helper that drives the vdev TDI state machine
>   via RHI host calls and translates the firmware status codes

...

> +
> +bool rhi_has_da_support(void)
> +{
> +	int ret;
> +
> +	struct rsi_host_call *rhi_call __free(kfree) =
> +		kmalloc(sizeof(*rhi_call), GFP_KERNEL);

Same comment as before that kzalloc is best practice for struct
rsi_host_call.

> +	if (!rhi_call)
> +		return -ENOMEM;

Returning an error value in a bool function will evaluate to true. This is
probably not your intended behavior.

Regards,
Kameron

> +
> +	rhi_call->imm = 0;
> +	rhi_call->gprs[0] = RHI_DA_FEATURES;
> +
> +	ret = rsi_host_call(rhi_call);
> +	if (ret != RSI_SUCCESS || rhi_call->gprs[0] == SMCCC_RET_NOT_SUPPORTED)
> +		return false;
> +
> +	/* For base DA to work we need these to be supported */
> +	if ((rhi_call->gprs[0] & RHI_DA_BASE_FEATURE) == RHI_DA_BASE_FEATURE)
> +		return true;
> +
> +	return false;
> +}...