Re: [PATCH v4 11/14] KVM: arm64: Add newly allocated ID registers to register descriptions

[Marc Zyngier]

On Mon, 22 Jan 2024 16:28:14 +0000,
Mark Brown <broonie@xxxxxxxxxx> wrote:
> 
> The 2023 architecture extensions have allocated some new ID registers, add
> them to the KVM system register descriptions so that they are visible to
> guests.
> 
> Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
> ---
>  arch/arm64/kvm/sys_regs.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 30253bd19917..38503b1cd2eb 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -2292,12 +2292,12 @@ static const struct sys_reg_desc sys_reg_descs[] = {
>  		   ID_AA64PFR0_EL1_AdvSIMD |
>  		   ID_AA64PFR0_EL1_FP), },
>  	ID_SANITISED(ID_AA64PFR1_EL1),
> -	ID_UNALLOCATED(4,2),
> +	ID_SANITISED(ID_AA64PFR2_EL1),

So you now expose all sort of MTE things to the guest?

>  	ID_UNALLOCATED(4,3),
>  	ID_WRITABLE(ID_AA64ZFR0_EL1, ~ID_AA64ZFR0_EL1_RES0),
>  	ID_HIDDEN(ID_AA64SMFR0_EL1),
>  	ID_UNALLOCATED(4,6),
> -	ID_UNALLOCATED(4,7),
> +	ID_SANITISED(ID_AA64FPFR0_EL1),
>  
>  	/* CRm=5 */
>  	{ SYS_DESC(SYS_ID_AA64DFR0_EL1),
> @@ -2324,7 +2324,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
>  	ID_WRITABLE(ID_AA64ISAR2_EL1, ~(ID_AA64ISAR2_EL1_RES0 |
>  					ID_AA64ISAR2_EL1_APA3 |
>  					ID_AA64ISAR2_EL1_GPA3)),
> -	ID_UNALLOCATED(6,3),
> +	ID_WRITABLE(ID_AA64ISAR3_EL1, ~ID_AA64ISAR3_EL1_RES0),

How about the non dpISA stuff that is advertised in the same register,
and for which no support exists?

>  	ID_UNALLOCATED(6,4),
>  	ID_UNALLOCATED(6,5),
>  	ID_UNALLOCATED(6,6),
> 

	M.

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