Patchwork [v3,3/8] arm64: KVM: Install stage-2 translation before enabling traps

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Submitter Marc Zyngier
Date Dec. 6, 2018, 5:31 p.m.
Message ID <20181206173126.139877-4-marc.zyngier@arm.com>
Download mbox | patch
Permalink /patch/674453/
State New
Headers show

Comments

Marc Zyngier - Dec. 6, 2018, 5:31 p.m.
It is a bit odd that we only install stage-2 translation after having
cleared HCR_EL2.TGE, which means that there is a window during which
AT requests could fail as stage-2 is not configured yet.

Let's move stage-2 configuration before we clear TGE, making the
guest entry sequence clearer: we first configure all the guest stuff,
then only switch to the guest translation regime.

While we're at it, do the same thing for !VHE. It doesn't hurt,
and keeps things symmetric.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/hyp/switch.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
Christoffer Dall - Dec. 10, 2018, 10:13 a.m.
On Thu, Dec 06, 2018 at 05:31:21PM +0000, Marc Zyngier wrote:
> It is a bit odd that we only install stage-2 translation after having
> cleared HCR_EL2.TGE, which means that there is a window during which
> AT requests could fail as stage-2 is not configured yet.
> 
> Let's move stage-2 configuration before we clear TGE, making the
> guest entry sequence clearer: we first configure all the guest stuff,
> then only switch to the guest translation regime.
> 
> While we're at it, do the same thing for !VHE. It doesn't hurt,
> and keeps things symmetric.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
>  arch/arm64/kvm/hyp/switch.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
> index 7cc175c88a37..a8fa61c68c32 100644
> --- a/arch/arm64/kvm/hyp/switch.c
> +++ b/arch/arm64/kvm/hyp/switch.c
> @@ -499,8 +499,8 @@ int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
>  
>  	sysreg_save_host_state_vhe(host_ctxt);
>  
> -	__activate_traps(vcpu);
>  	__activate_vm(vcpu->kvm);
> +	__activate_traps(vcpu);
>  
>  	sysreg_restore_guest_state_vhe(guest_ctxt);
>  	__debug_switch_to_guest(vcpu);
> @@ -545,8 +545,8 @@ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
>  
>  	__sysreg_save_state_nvhe(host_ctxt);
>  
> -	__activate_traps(vcpu);
>  	__activate_vm(kern_hyp_va(vcpu->kvm));
> +	__activate_traps(vcpu);
>  
>  	__hyp_vgic_restore_state(vcpu);
>  	__timer_enable_traps(vcpu);
> -- 
> 2.19.2
> 

Acked-by: Christoffer Dall <christoffer.dall@arm.com>

Patch

diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index 7cc175c88a37..a8fa61c68c32 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -499,8 +499,8 @@  int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
 
 	sysreg_save_host_state_vhe(host_ctxt);
 
-	__activate_traps(vcpu);
 	__activate_vm(vcpu->kvm);
+	__activate_traps(vcpu);
 
 	sysreg_restore_guest_state_vhe(guest_ctxt);
 	__debug_switch_to_guest(vcpu);
@@ -545,8 +545,8 @@  int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
 
 	__sysreg_save_state_nvhe(host_ctxt);
 
-	__activate_traps(vcpu);
 	__activate_vm(kern_hyp_va(vcpu->kvm));
+	__activate_traps(vcpu);
 
 	__hyp_vgic_restore_state(vcpu);
 	__timer_enable_traps(vcpu);