Re: [PATCH v4 02/14] arm64/fpsimd: Enable host kernel access to FPMR

From: Marc Zyngier
Date: Fri Feb 23 2024 - 06:34:13 EST


On Mon, 22 Jan 2024 16:28:05 +0000,
Mark Brown <broonie@xxxxxxxxxx> wrote:
>
> FEAT_FPMR provides a new generally accessible architectural register FPMR.
> This is only accessible to EL0 and EL1 when HCRX_EL2.EnFPM is set to 1,
> do this when the host is running. The guest part will be done along with
> context switching the new register and exposing it via guest management.
>
> Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
> ---
> arch/arm64/include/asm/kvm_arm.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
> index 3c6f8ba1e479..7f45ce9170bb 100644
> --- a/arch/arm64/include/asm/kvm_arm.h
> +++ b/arch/arm64/include/asm/kvm_arm.h
> @@ -105,7 +105,7 @@
> #define HCRX_GUEST_FLAGS \
> (HCRX_EL2_SMPME | HCRX_EL2_TCR2En | \
> (cpus_have_final_cap(ARM64_HAS_MOPS) ? (HCRX_EL2_MSCEn | HCRX_EL2_MCE2) : 0))
> -#define HCRX_HOST_FLAGS (HCRX_EL2_MSCEn | HCRX_EL2_TCR2En)
> +#define HCRX_HOST_FLAGS (HCRX_EL2_MSCEn | HCRX_EL2_TCR2En | HCRX_EL2_EnFPM)
>
> /* TCR_EL2 Registers bits */
> #define TCR_EL2_DS (1UL << 32)
>

Acked-by: Marc Zyngier <maz@xxxxxxxxxx>

M.

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