RE: [PATCH] smccc: kvm_guest: Align with DISCOVER_IMPL_CPUS ABI

[Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>]

> -----Original Message-----
> From: Oliver Upton <oliver.upton@linux.dev>
> Sent: Thursday, March 27, 2025 4:36 PM
> To: kvmarm@lists.linux.dev
> Cc: linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org;
> Mark Rutland <mark.rutland@arm.com>; Lorenzo Pieralisi
> <lpieralisi@kernel.org>; Sudeep Holla <sudeep.holla@arm.com>; Catalin
> Marinas <catalin.marinas@arm.com>; Marc Zyngier <maz@kernel.org>;
> Oliver Upton <oliver.upton@linux.dev>; Shameerali Kolothum Thodi
> <shameerali.kolothum.thodi@huawei.com>
> Subject: [PATCH] smccc: kvm_guest: Align with DISCOVER_IMPL_CPUS ABI
> 
> The ABI of the hypercall requires that R2 and R3 are 0. Explicitly pass
> 0 for these parameters.
> 
> Cc: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> Fixes: 86edf6bdcf05 ("smccc/kvm_guest: Enable errata based on
> implementation CPUs")
> Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

Reviewed-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>

Thanks,
Shameer

> ---
>  drivers/firmware/smccc/kvm_guest.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/firmware/smccc/kvm_guest.c
> b/drivers/firmware/smccc/kvm_guest.c
> index 5767aed25cdc..ac2d3cf8a776 100644
> --- a/drivers/firmware/smccc/kvm_guest.c
> +++ b/drivers/firmware/smccc/kvm_guest.c
> @@ -95,7 +95,7 @@ void  __init kvm_arm_target_impl_cpu_init(void)
> 
>  	for (i = 0; i < max_cpus; i++) {
> 
> 	arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_DISCOVE
> R_IMPL_CPUS_FUNC_ID,
> -				     i, &res);
> +				     i, 0, 0, &res);
>  		if (res.a0 != SMCCC_RET_SUCCESS) {
>  			pr_warn("Discovering target implementation CPUs
> failed\n");
>  			goto mem_free;
> 
> base-commit: 369c0122682c4468a69f2454614eded71c5348f3
> --
> 2.39.5