[PATCH v3 10/41] KVM: arm64: Move debug dirty flag calculation out of world switch

[Julien Thierry]

On 12/01/18 12:07, Christoffer Dall wrote:
> There is no need to figure out inside the world-switch if we should
> save/restore the debug registers or not, we can might as well do that in

Nit: -can*

> the higher level debug setup code, making it easier to optimize down the
> line.
> 
> Reviewed-by: Marc Zyngier <marc.zyngier at arm.com>
> Signed-off-by: Christoffer Dall <christoffer.dall at linaro.org>

Reviewed-by: Julien Thierry <julien.thierry at arm.com>

> ---
>   arch/arm64/kvm/debug.c        | 5 +++++
>   arch/arm64/kvm/hyp/debug-sr.c | 6 ------
>   2 files changed, 5 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c
> index fa63b28c65e0..feedb877cff8 100644
> --- a/arch/arm64/kvm/debug.c
> +++ b/arch/arm64/kvm/debug.c
> @@ -193,6 +193,11 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
>   	if (trap_debug)
>   		vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA;
>   
> +	/* If KDE or MDE are set, perform a full save/restore cycle. */
> +	if ((vcpu_sys_reg(vcpu, MDSCR_EL1) & DBG_MDSCR_KDE) ||
> +	    (vcpu_sys_reg(vcpu, MDSCR_EL1) & DBG_MDSCR_MDE))
> +		vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
> +
>   	trace_kvm_arm_set_dreg32("MDCR_EL2", vcpu->arch.mdcr_el2);
>   	trace_kvm_arm_set_dreg32("MDSCR_EL1", vcpu_sys_reg(vcpu, MDSCR_EL1));
>   }
> diff --git a/arch/arm64/kvm/hyp/debug-sr.c b/arch/arm64/kvm/hyp/debug-sr.c
> index 321c9c05dd9e..406829b6a43e 100644
> --- a/arch/arm64/kvm/hyp/debug-sr.c
> +++ b/arch/arm64/kvm/hyp/debug-sr.c
> @@ -162,12 +162,6 @@ void __hyp_text __debug_restore_state(struct kvm_vcpu *vcpu,
>   
>   void __hyp_text __debug_cond_save_host_state(struct kvm_vcpu *vcpu)
>   {
> -	/* If any of KDE, MDE or KVM_ARM64_DEBUG_DIRTY is set, perform
> -	 * a full save/restore cycle. */
> -	if ((vcpu->arch.ctxt.sys_regs[MDSCR_EL1] & DBG_MDSCR_KDE) ||
> -	    (vcpu->arch.ctxt.sys_regs[MDSCR_EL1] & DBG_MDSCR_MDE))
> -		vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
> -
>   	__debug_save_state(vcpu, &vcpu->arch.host_debug_state.regs,
>   			   kern_hyp_va(vcpu->arch.host_cpu_context));
>   	__debug_save_spe()(&vcpu->arch.host_debug_state.pmscr_el1);
> 

-- 
Julien Thierry