[PATCH 03/18] KVM: arm64: pkvm: Save host FPMR in host cpu context

[Vladimir Murzin]

On 5/21/26 14:25, Mark Rutland wrote:
> Protected KVM stores most of the host's system register state in
> kvm_host_data::host_ctxt, which is an instance of struct
> kvm_cpu_context. As kvm_cpu_context::sys_regs[] has a slot for FPMR, we
> can store the host's FPMR there.
> 
> Do so, and remove kvm_host_data::fpmr.
> 
> Signed-off-by: Mark Rutland <mark.rutland at arm.com>
> Cc: Catalin Marinas <catalin.marinas at arm.com>
> Cc: Fuad Tabba <tabba at google.com>
> Cc: James Morse <james.morse at arm.com>
> Cc: Marc Zyngier <maz at kernel.org>
> Cc: Mark Brown <broonie at kernel.org>
> Cc: Oliver Upton <oupton at kernel.org>
> Cc: Will Deacon <will at kernel.org>
> ---
>  arch/arm64/include/asm/kvm_host.h       | 3 ---
>  arch/arm64/kvm/hyp/include/hyp/switch.h | 6 ++++--
>  arch/arm64/kvm/hyp/nvhe/hyp-main.c      | 5 +++--
>  3 files changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index 65eead8362e0b..42b1c4764a4bf 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -775,9 +775,6 @@ struct kvm_host_data {
>  	 */
>  	struct cpu_sve_state *sve_state;
>  
> -	/* Used by pKVM only. */
> -	u64	fpmr;
> -
>  	/* Ownership of the FP regs */
>  	enum {
>  		FP_STATE_FREE,
> diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
> index 98b2976837b11..cc4d011a2b380 100644
> --- a/arch/arm64/kvm/hyp/include/hyp/switch.h
> +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
> @@ -554,6 +554,8 @@ static inline void fpsimd_lazy_switch_to_host(struct kvm_vcpu *vcpu)
>  
>  static void kvm_hyp_save_fpsimd_host(struct kvm_vcpu *vcpu)
>  {
> +	struct kvm_cpu_context *hctxt = host_data_ptr(host_ctxt);
> +
>  	/*
>  	 * Non-protected kvm relies on the host restoring its sve state.
>  	 * Protected kvm restores the host's sve state as not to reveal that
> @@ -562,11 +564,11 @@ static void kvm_hyp_save_fpsimd_host(struct kvm_vcpu *vcpu)
>  	if (system_supports_sve()) {
>  		__hyp_sve_save_host();
>  	} else {
> -		__fpsimd_save_state(host_data_ptr(host_ctxt.fp_regs));
> +		__fpsimd_save_state(&hctxt->fp_regs);
>  	}
>  
>  	if (kvm_has_fpmr(kern_hyp_va(vcpu->kvm)))
> -		*host_data_ptr(fpmr) = read_sysreg_s(SYS_FPMR);
> +		ctxt_sys_reg(hctxt, FPMR) = read_sysreg_s(SYS_FPMR);
>  }
>  
>  
> diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
> index 06db299c37a89..db60f770060e5 100644
> --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
> +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
> @@ -66,6 +66,7 @@ static void fpsimd_sve_flush(void)
>  
>  static void fpsimd_sve_sync(struct kvm_vcpu *vcpu)
>  {
> +	struct kvm_cpu_context *hctxt = host_data_ptr(host_ctxt);
>  	bool has_fpmr;
>  
>  	if (!guest_owns_fp_regs())
> @@ -89,10 +90,10 @@ static void fpsimd_sve_sync(struct kvm_vcpu *vcpu)
>  	if (system_supports_sve())
>  		__hyp_sve_restore_host();
>  	else
> -		__fpsimd_restore_state(host_data_ptr(host_ctxt.fp_regs));
> +		__fpsimd_restore_state(&hctxt->fp_regs);
>  
>  	if (has_fpmr)
> -		write_sysreg_s(*host_data_ptr(fpmr), SYS_FPMR);
> +		write_sysreg_s(ctxt_sys_reg(hctxt, FPMR), SYS_FPMR);
>  
>  	*host_data_ptr(fp_owner) = FP_STATE_HOST_OWNED;
>  }
> -- 2.30.2
> 

FWIW,

Reviewed-by: Vladimir Murzin <vladimir.murzin at arm.com>