On Mon, 23 Nov 2015 10:47:10 +0000 Steve Capper <steve.capper@xxxxxxxxxx> wrote: Hi Steve, > On Mon, Nov 16, 2015 at 01:11:43PM +0000, Marc Zyngier wrote: > > Implement the timer save restore as a direct translation of > > the assembly code version. > > Hi Marc, some comments below. > Cheers, > -- > Steve > > > > > Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx> > > --- > > arch/arm64/kvm/hyp/Makefile | 1 + > > arch/arm64/kvm/hyp/hyp.h | 3 ++ > > arch/arm64/kvm/hyp/timer-sr.c | 68 > > +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 72 > > insertions(+) create mode 100644 arch/arm64/kvm/hyp/timer-sr.c > > > > diff --git a/arch/arm64/kvm/hyp/Makefile > > b/arch/arm64/kvm/hyp/Makefile index d1e38ce..455dc0a 100644 > > --- a/arch/arm64/kvm/hyp/Makefile > > +++ b/arch/arm64/kvm/hyp/Makefile > > @@ -4,3 +4,4 @@ > > > > obj-$(CONFIG_KVM_ARM_HOST) += vgic-v2-sr.o > > obj-$(CONFIG_KVM_ARM_HOST) += vgic-v3-sr.o > > +obj-$(CONFIG_KVM_ARM_HOST) += timer-sr.o > > diff --git a/arch/arm64/kvm/hyp/hyp.h b/arch/arm64/kvm/hyp/hyp.h > > index a31cb6e..86aa5a2 100644 > > --- a/arch/arm64/kvm/hyp/hyp.h > > +++ b/arch/arm64/kvm/hyp/hyp.h > > @@ -33,5 +33,8 @@ void __vgic_v2_restore_state(struct kvm_vcpu > > *vcpu); void __vgic_v3_save_state(struct kvm_vcpu *vcpu); > > void __vgic_v3_restore_state(struct kvm_vcpu *vcpu); > > > > +void __timer_save_state(struct kvm_vcpu *vcpu); > > +void __timer_restore_state(struct kvm_vcpu *vcpu); > > + > > #endif /* __ARM64_KVM_HYP_H__ */ > > > > diff --git a/arch/arm64/kvm/hyp/timer-sr.c > > b/arch/arm64/kvm/hyp/timer-sr.c new file mode 100644 > > index 0000000..1a1d2ac > > --- /dev/null > > +++ b/arch/arm64/kvm/hyp/timer-sr.c > > @@ -0,0 +1,68 @@ > > +/* > > + * Copyright (C) 2012-2015 - ARM Ltd > > + * Author: Marc Zyngier <marc.zyngier@xxxxxxx> > > + * > > + * This program is free software; you can redistribute it and/or > > modify > > + * it under the terms of the GNU General Public License version 2 > > as > > + * published by the Free Software Foundation. > > + * > > + * This program is distributed in the hope that it will be useful, > > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > > + * GNU General Public License for more details. > > + * > > + * You should have received a copy of the GNU General Public > > License > > + * along with this program. If not, see > > <http://www.gnu.org/licenses/>. > > + */ > > + > > +#include <linux/compiler.h> > > +#include <linux/kvm_host.h> > > + > > +#include <asm/kvm_mmu.h> > > + > > +#include "hyp.h" > > + > > +/* vcpu is already in the HYP VA space */ > > +void __hyp_text __timer_save_state(struct kvm_vcpu *vcpu) > > +{ > > + struct kvm *kvm = kern_hyp_va(vcpu->kvm); > > + struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; > > + > > + if (kvm->arch.timer.enabled) { > > + timer->cntv_ctl = read_sysreg(cntv_ctl_el0); > > The old assembler version ands this value with 3 before storing it. > Are we not worried about the ISTATUS bit? Not really. It could even be useful to find out about it, to be honest. > > > + isb(); > > + timer->cntv_cval = read_sysreg(cntv_cval_el0); > > + } > > + > > + /* Disable the virtual timer */ > > + write_sysreg(0, cntv_ctl_el0); > > + > > + /* Allow physical timer/counter access for the host */ > > + write_sysreg(read_sysreg(cnthctl_el2) | 3, cnthctl_el2); > > nit: EL1PCTEN | EL1PCEN or something similar? Sure. > > + > > + /* Clear cntvoff for the host */ > > + write_sysreg(0, cntvoff_el2); > > +} > > + > > +void __hyp_text __timer_restore_state(struct kvm_vcpu *vcpu) > > +{ > > + struct kvm *kvm = kern_hyp_va(vcpu->kvm); > > + struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; > > + u64 val; > > + > > + /* > > + * Disallow physical timer access for the guest > > + * Physical counter access is allowed > > + */ > > + val = read_sysreg(cnthctl_el2); > > + val &= ~(1 << 1); > > + val |= 1; > > Similar nit here about constants. > > > + write_sysreg(val, cnthctl_el2); > > + > > + if (kvm->arch.timer.enabled) { > > + write_sysreg(kvm->arch.timer.cntvoff, cntvoff_el2); > > + write_sysreg(timer->cntv_cval, cntv_cval_el0); > > + isb(); > > + write_sysreg(timer->cntv_ctl, cntv_ctl_el0); > > In the assembler version we and cntv_ctl with 3 before writing to > cntv_ctl_el0. ISTATUS is RO, so masking it was a bit useless. Thanks, M. -- Jazz is not dead. It just smells funny. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
