[PATCH v4 31/40] KVM: arm64: Move common VHE/non-VHE trap config in separate functions

[Julien Grall]

Hi Christoffer,

On 15/02/18 21:03, Christoffer Dall wrote:
> @@ -85,37 +123,14 @@ static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu)
>   {
>   	u64 hcr = vcpu->arch.hcr_el2;
>   
> -	/*
> -	 * We are about to set CPTR_EL2.TFP to trap all floating point
> -	 * register accesses to EL2, however, the ARM ARM clearly states that
> -	 * traps are only taken to EL2 if the operation would not otherwise
> -	 * trap to EL1.  Therefore, always make sure that for 32-bit guests,
> -	 * we set FPEXC.EN to prevent traps to EL1, when setting the TFP bit.
> -	 * If FP/ASIMD is not implemented, FPEXC is UNDEFINED and any access to
> -	 * it will cause an exception.
> -	 */
> -	if (vcpu_el1_is_32bit(vcpu) && system_supports_fpsimd()) {
> -		write_sysreg(1 << 30, fpexc32_el2);
> -		isb();
> -	}
> +	write_sysreg(hcr, hcr_el2);
>   
>   	if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN) && (hcr & HCR_VSE))
>   		write_sysreg_s(vcpu->arch.vsesr_el2, SYS_VSESR_EL2);
>   
> -	write_sysreg(hcr, hcr_el2);

OOI, any reason to move the write to HCR_EL2 just before the if?

> -
> -	/* Trap on AArch32 cp15 c15 accesses (EL1 or EL0) */
> -	write_sysreg(1 << 15, hstr_el2);
> -	/*
> -	 * Make sure we trap PMU access from EL0 to EL2. Also sanitize
> -	 * PMSELR_EL0 to make sure it never contains the cycle
> -	 * counter, which could make a PMXEVCNTR_EL0 access UNDEF at
> -	 * EL1 instead of being trapped to EL2.
> -	 */
> -	write_sysreg(0, pmselr_el0);
> -	write_sysreg(ARMV8_PMU_USERENR_MASK, pmuserenr_el0);
> -	write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2);
> -	__activate_traps_arch()();
> +	__activate_traps_fpsimd32(vcpu);
> +	__activate_traps_common(vcpu);
> +	__activate_traps_arch()(vcpu);
>   }
>   
>   static void __hyp_text __deactivate_traps_vhe(void)
> @@ -160,9 +175,8 @@ static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu)
>   	if (vcpu->arch.hcr_el2 & HCR_VSE)
>   		vcpu->arch.hcr_el2 = read_sysreg(hcr_el2);
>   
> +	__deactivate_traps_common();
>   	__deactivate_traps_arch()();
> -	write_sysreg(0, hstr_el2);
> -	write_sysreg(0, pmuserenr_el0);
>   }
>   
>   static void __hyp_text __activate_vm(struct kvm *kvm)
> 

Cheers,

-- 
Julien Grall