On Mon, Dec 11, 2017 at 10:02:58AM +0000, Marc Zyngier wrote:
> On 07/12/17 17:06, Christoffer Dall wrote:
> > The VHE switch function calls __timer_enable_traps and
> > __timer_disable_traps which don't do anything on VHE systems.
> > Therefore, simply remove these calls from the VHE switch function and
> > make the functions non-conditional as they are now only called from the
> > non-VHE switch path.
> >
> > Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
> > ---
> > arch/arm64/kvm/hyp/switch.c | 2 --
> > virt/kvm/arm/hyp/timer-sr.c | 36 ++++++++++++++----------------------
> > 2 files changed, 14 insertions(+), 24 deletions(-)
> >
> > diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
> > index e783e2371b7c..09aafa0470f7 100644
> > --- a/arch/arm64/kvm/hyp/switch.c
> > +++ b/arch/arm64/kvm/hyp/switch.c
> > @@ -358,7 +358,6 @@ int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
> > __activate_vm(vcpu->kvm);
> >
> > __vgic_restore_state(vcpu);
> > - __timer_enable_traps(vcpu);
> >
> > /*
> > * We must restore the 32-bit state before the sysregs, thanks
> > @@ -377,7 +376,6 @@ int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
> >
> > __sysreg_save_guest_state(guest_ctxt);
> > __sysreg32_save_state(vcpu);
> > - __timer_disable_traps(vcpu);
> > __vgic_save_state(vcpu);
> >
> > __deactivate_traps(vcpu);
> > diff --git a/virt/kvm/arm/hyp/timer-sr.c b/virt/kvm/arm/hyp/timer-sr.c
> > index f24404b3c8df..752b37f9133c 100644
> > --- a/virt/kvm/arm/hyp/timer-sr.c
> > +++ b/virt/kvm/arm/hyp/timer-sr.c
> > @@ -29,32 +29,24 @@ void __hyp_text __kvm_timer_set_cntvoff(u32 cntvoff_low, u32 cntvoff_high)
> >
> > void __hyp_text __timer_disable_traps(struct kvm_vcpu *vcpu)
> > {
> > - /*
> > - * We don't need to do this for VHE since the host kernel runs in EL2
> > - * with HCR_EL2.TGE ==1, which makes those bits have no impact.
> > - */
> > - if (!has_vhe()) {
> > - u64 val;
> > + u64 val;
> >
> > - /* Allow physical timer/counter access for the host */
> > - val = read_sysreg(cnthctl_el2);
> > - val |= CNTHCTL_EL1PCTEN | CNTHCTL_EL1PCEN;
> > - write_sysreg(val, cnthctl_el2);
> > - }
> > + /* Allow physical timer/counter access for the host */
> > + val = read_sysreg(cnthctl_el2);
> > + val |= CNTHCTL_EL1PCTEN | CNTHCTL_EL1PCEN;
> > + write_sysreg(val, cnthctl_el2);
> > }
> >
> > void __hyp_text __timer_enable_traps(struct kvm_vcpu *vcpu)
> > {
> > - if (!has_vhe()) {
> > - u64 val;
> > + u64 val;
> >
> > - /*
> > - * Disallow physical timer access for the guest
> > - * Physical counter access is allowed
> > - */
> > - val = read_sysreg(cnthctl_el2);
> > - val &= ~CNTHCTL_EL1PCEN;
> > - val |= CNTHCTL_EL1PCTEN;
> > - write_sysreg(val, cnthctl_el2);
> > - }
> > + /*
> > + * Disallow physical timer access for the guest
> > + * Physical counter access is allowed
> > + */
> > + val = read_sysreg(cnthctl_el2);
> > + val &= ~CNTHCTL_EL1PCEN;
> > + val |= CNTHCTL_EL1PCTEN;
> > + write_sysreg(val, cnthctl_el2);
> > }
> >
>
> Since we're not testing for !VHE anymore, can you add a small comment
> saying that these two function are for the benefit of !VHE only and
> shouldn't be called on VHE?
Yes, absolutely:
diff --git a/virt/kvm/arm/hyp/timer-sr.c b/virt/kvm/arm/hyp/timer-sr.c
index 752b37f9133c..77754a62eb0c 100644
--- a/virt/kvm/arm/hyp/timer-sr.c
+++ b/virt/kvm/arm/hyp/timer-sr.c
@@ -27,6 +27,10 @@ void __hyp_text __kvm_timer_set_cntvoff(u32 cntvoff_low, u32 cntvoff_high)
write_sysreg(cntvoff, cntvoff_el2);
}
+/*
+ * Should only be called on non-VHE systems.
+ * VHE systems use EL2 timers and configure EL1 timers in kvm_timer_init_vhe().
+ */
void __hyp_text __timer_disable_traps(struct kvm_vcpu *vcpu)
{
u64 val;
@@ -37,6 +41,10 @@ void __hyp_text __timer_disable_traps(struct kvm_vcpu *vcpu)
write_sysreg(val, cnthctl_el2);
}
+/*
+ * Should only be called on non-VHE systems.
+ * VHE systems use EL2 timers and configure EL1 timers in kvm_timer_init_vhe().
+ */
void __hyp_text __timer_enable_traps(struct kvm_vcpu *vcpu)
{
u64 val;
>
> Otherwise,
>
> Acked-by: Marc Zyngier <marc.zyngier@xxxxxxx>
>
Thanks,
-Christoffer
