[PATCH] KVM: arm64: Convert ICH_HCR_EL2_TDIR cap to EARLY_LOCAL_CPU_FEATURE

[Suzuki K Poulose]

On 25/11/2025 16:01, Marc Zyngier wrote:
> Suzuki notices that making the ICH_HCR_EL2_TDIR capability a system
> one isn't a very good idea, should we end-up with CPUs that have
> asymmetric TDIR support (somehow unlikely, but you never know what
> level of stupidity vendors are up to). For this hypothetical setup,
> making this an "EARLY_LOCAL_CPU_FEATURE" is a much better option.
> 
> This is actually consistent with what we already do with GICv5
> legacy interface, so flip the capability over.
> 
> Reported-by: Suzuki K Poulose <suzuki.poulose at arm.com>
> Signed-off-by: Marc Zyngier <maz at kernel.org>
> Fixes: 2a28810cbb8b2 ("KVM: arm64: GICv3: Detect and work around the lack of ICV_DIR_EL1 trapping")
> Link: https://lore.kerenl.org/r/5df713d4-8b79-4456-8fd1-707ca89a61b6@arm.com

Reviewed-by: Suzuki K Poulose <suzuki.poulose at arm.com>

> ---
>   arch/arm64/kernel/cpufeature.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> index 5de51cb1b8fe2..75fb9a0efcc8e 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -2325,14 +2325,14 @@ static bool can_trap_icv_dir_el1(const struct arm64_cpu_capabilities *entry,
>   
>   	BUILD_BUG_ON(ARM64_HAS_ICH_HCR_EL2_TDIR <= ARM64_HAS_GICV3_CPUIF);
>   	BUILD_BUG_ON(ARM64_HAS_ICH_HCR_EL2_TDIR <= ARM64_HAS_GICV5_LEGACY);
> -	if (!cpus_have_cap(ARM64_HAS_GICV3_CPUIF) &&
> +	if (!this_cpu_has_cap(ARM64_HAS_GICV3_CPUIF) &&
>   	    !is_midr_in_range_list(has_vgic_v3))
>   		return false;
>   
>   	if (!is_hyp_mode_available())
>   		return false;
>   
> -	if (cpus_have_cap(ARM64_HAS_GICV5_LEGACY))
> +	if (this_cpu_has_cap(ARM64_HAS_GICV5_LEGACY))
>   		return true;
>   
>   	if (is_kernel_in_hyp_mode())
> @@ -2863,7 +2863,7 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
>   		 */
>   		.desc = "ICV_DIR_EL1 trapping",
>   		.capability = ARM64_HAS_ICH_HCR_EL2_TDIR,
> -		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
> +		.type = ARM64_CPUCAP_EARLY_LOCAL_CPU_FEATURE,
>   		.matches = can_trap_icv_dir_el1,
>   	},
>   #ifdef CONFIG_ARM64_E0PD