Re: [PATCH v16 2/6] KVM: arm64: Manage GCS access and registers for guests

[Marc Zyngier <maz@kernel.org>]

On Fri, 12 Sep 2025 10:25:28 +0100,
Mark Brown <broonie@kernel.org> wrote:
> 
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 82ffb3b3b3cf..03fb2dce0b80 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -138,6 +138,8 @@ static bool get_el2_to_el1_mapping(unsigned int reg,
>  		MAPPED_EL2_SYSREG(PIR_EL2,     PIR_EL1,     NULL	     );
>  		MAPPED_EL2_SYSREG(PIRE0_EL2,   PIRE0_EL1,   NULL	     );
>  		MAPPED_EL2_SYSREG(POR_EL2,     POR_EL1,     NULL	     );
> +		MAPPED_EL2_SYSREG(GCSCR_EL2,   GCSCR_EL1,   NULL             );
> +		MAPPED_EL2_SYSREG(GCSPR_EL2,   GCSPR_EL1,   NULL             );
>  		MAPPED_EL2_SYSREG(AMAIR_EL2,   AMAIR_EL1,   NULL	     );
>  		MAPPED_EL2_SYSREG(ELR_EL2,     ELR_EL1,	    NULL	     );
>  		MAPPED_EL2_SYSREG(SPSR_EL2,    SPSR_EL1,    NULL	     );

Just like the previous version, you're missing the accessors that
would be this table useful. Meaning that the vcpu_read_sys_reg() and
vcpu_write_sys_reg() accessors will fail for all 4 GSC registers.

	M.

-- 
Without deviation from the norm, progress is not possible.