On 30/11/15 19:59, Christoffer Dall wrote: > On Fri, Nov 27, 2015 at 06:49:59PM +0000, Marc Zyngier wrote: >> Implement the timer save restore as a direct translation of >> the assembly code version. >> >> 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 | 71 ++++++++++++++++++++++++++++++++++++ >> include/clocksource/arm_arch_timer.h | 6 +++ >> 4 files changed, 81 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..8e2209c >> --- /dev/null >> +++ b/arch/arm64/kvm/hyp/timer-sr.c >> @@ -0,0 +1,71 @@ >> +/* >> + * 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 <clocksource/arm_arch_timer.h> >> +#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); >> + 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) | CNTHCTL_EL1PCTEN | >> + CNTHCTL_EL1PCEN), >> + cnthctl_el2); > > nit: again I probably prefer reading cnthctl_el2 into a variable, modify > the bits and write it back, but it's no big deal. Sure. >> + >> + /* Clear cntvoff for the host */ >> + write_sysreg(0, cntvoff_el2); > > why do we do this when we've just disabled the timer? Because the host does use CNTVCT_EL0 (see the VDSO code), and you don't want time to go backward over there... >> +} >> + >> +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 &= ~CNTHCTL_EL1PCEN; >> + val |= CNTHCTL_EL1PCTEN; >> + 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); >> + } >> +} >> diff --git a/include/clocksource/arm_arch_timer.h b/include/clocksource/arm_arch_timer.h >> index 9916d0e..25d0914 100644 >> --- a/include/clocksource/arm_arch_timer.h >> +++ b/include/clocksource/arm_arch_timer.h >> @@ -23,6 +23,12 @@ >> #define ARCH_TIMER_CTRL_IT_MASK (1 << 1) >> #define ARCH_TIMER_CTRL_IT_STAT (1 << 2) >> >> +#define CNTHCTL_EL1PCTEN (1 << 0) >> +#define CNTHCTL_EL1PCEN (1 << 1) >> +#define CNTHCTL_EVNTEN (1 << 2) >> +#define CNTHCTL_EVNTDIR (1 << 3) >> +#define CNTHCTL_EVNTI (0xF << 4) >> + >> enum arch_timer_reg { >> ARCH_TIMER_REG_CTRL, >> ARCH_TIMER_REG_TVAL, >> -- >> 2.1.4 >> > > Otherwise this looks good. 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
