[PATCH 06/20] KVM: arm64: Inherit RESx bits from FGT register descriptors

[Joey Gouly]

On Mon, Jan 26, 2026 at 12:16:40PM +0000, Marc Zyngier wrote:
> The FGT registers have their computed RESx bits stashed in specific
> descriptors, which we can easily use when computing the masks used
> for the guest.
> 
> This removes a bit of boilerplate code.

Reviewed-by: Joey Gouly <joey.gouly at arm.com>

> 
> Signed-off-by: Marc Zyngier <maz at kernel.org>
> ---
>  arch/arm64/kvm/config.c | 16 +++++-----------
>  1 file changed, 5 insertions(+), 11 deletions(-)
> 
> diff --git a/arch/arm64/kvm/config.c b/arch/arm64/kvm/config.c
> index a907195bd44b6..8d152605999ba 100644
> --- a/arch/arm64/kvm/config.c
> +++ b/arch/arm64/kvm/config.c
> @@ -1344,6 +1344,11 @@ struct resx compute_reg_resx_bits(struct kvm *kvm,
>  	resx = compute_resx_bits(kvm, r->bit_feat_map, r->bit_feat_map_sz,
>  				 require, exclude);
>  
> +	if (r->feat_map.flags & MASKS_POINTER) {
> +		resx.res0 |= r->feat_map.masks->res0;
> +		resx.res1 |= r->feat_map.masks->res1;
> +	}
> +
>  	tmp = compute_resx_bits(kvm, &r->feat_map, 1, require, exclude);
>  
>  	resx.res0 |= tmp.res0;
> @@ -1424,47 +1429,36 @@ struct resx get_reg_fixed_bits(struct kvm *kvm, enum vcpu_sysreg reg)
>  	switch (reg) {
>  	case HFGRTR_EL2:
>  		resx = compute_reg_resx_bits(kvm, &hfgrtr_desc, 0, 0);
> -		resx.res1 |= HFGRTR_EL2_RES1;
>  		break;
>  	case HFGWTR_EL2:
>  		resx = compute_reg_resx_bits(kvm, &hfgwtr_desc, 0, 0);
> -		resx.res1 |= HFGWTR_EL2_RES1;
>  		break;
>  	case HFGITR_EL2:
>  		resx = compute_reg_resx_bits(kvm, &hfgitr_desc, 0, 0);
> -		resx.res1 |= HFGITR_EL2_RES1;
>  		break;
>  	case HDFGRTR_EL2:
>  		resx = compute_reg_resx_bits(kvm, &hdfgrtr_desc, 0, 0);
> -		resx.res1 |= HDFGRTR_EL2_RES1;
>  		break;
>  	case HDFGWTR_EL2:
>  		resx = compute_reg_resx_bits(kvm, &hdfgwtr_desc, 0, 0);
> -		resx.res1 |= HDFGWTR_EL2_RES1;
>  		break;
>  	case HAFGRTR_EL2:
>  		resx = compute_reg_resx_bits(kvm, &hafgrtr_desc, 0, 0);
> -		resx.res1 |= HAFGRTR_EL2_RES1;
>  		break;
>  	case HFGRTR2_EL2:
>  		resx = compute_reg_resx_bits(kvm, &hfgrtr2_desc, 0, 0);
> -		resx.res1 |= HFGRTR2_EL2_RES1;
>  		break;
>  	case HFGWTR2_EL2:
>  		resx = compute_reg_resx_bits(kvm, &hfgwtr2_desc, 0, 0);
> -		resx.res1 |= HFGWTR2_EL2_RES1;
>  		break;
>  	case HFGITR2_EL2:
>  		resx = compute_reg_resx_bits(kvm, &hfgitr2_desc, 0, 0);
> -		resx.res1 |= HFGITR2_EL2_RES1;
>  		break;
>  	case HDFGRTR2_EL2:
>  		resx = compute_reg_resx_bits(kvm, &hdfgrtr2_desc, 0, 0);
> -		resx.res1 |= HDFGRTR2_EL2_RES1;
>  		break;
>  	case HDFGWTR2_EL2:
>  		resx = compute_reg_resx_bits(kvm, &hdfgwtr2_desc, 0, 0);
> -		resx.res1 |= HDFGWTR2_EL2_RES1;
>  		break;
>  	case HCRX_EL2:
>  		resx = compute_reg_resx_bits(kvm, &hcrx_desc, 0, 0);
> -- 
> 2.47.3
>