From e59bff9bf302bf1332c6421b39ba2e82b84e63a6 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Mon, 4 Jan 2016 08:54:50 +0000 Subject: [PATCH] ARM: KVM: Add timer save/restore This patch shouldn't exist, as we should be able to reuse the arm64 version for free. I'll get there eventually, but in the meantime I need a timer ticking. Reviewed-by: Christoffer Dall Signed-off-by: Marc Zyngier --- arch/arm/kvm/hyp/Makefile | 1 + arch/arm/kvm/hyp/hyp.h | 8 +++++ arch/arm/kvm/hyp/timer-sr.c | 71 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 80 insertions(+) create mode 100644 arch/arm/kvm/hyp/timer-sr.c diff --git a/arch/arm/kvm/hyp/Makefile b/arch/arm/kvm/hyp/Makefile index 9f96fcb..9241ae8 100644 --- a/arch/arm/kvm/hyp/Makefile +++ b/arch/arm/kvm/hyp/Makefile @@ -4,3 +4,4 @@ obj-$(CONFIG_KVM_ARM_HOST) += tlb.o obj-$(CONFIG_KVM_ARM_HOST) += cp15-sr.o +obj-$(CONFIG_KVM_ARM_HOST) += timer-sr.o diff --git a/arch/arm/kvm/hyp/hyp.h b/arch/arm/kvm/hyp/hyp.h index ab2cb82..4924418 100644 --- a/arch/arm/kvm/hyp/hyp.h +++ b/arch/arm/kvm/hyp/hyp.h @@ -46,6 +46,9 @@ #define TTBR1 __ACCESS_CP15_64(1, c2) #define VTTBR __ACCESS_CP15_64(6, c2) #define PAR __ACCESS_CP15_64(0, c7) +#define CNTV_CVAL __ACCESS_CP15_64(3, c14) +#define CNTVOFF __ACCESS_CP15_64(4, c14) + #define CSSELR __ACCESS_CP15(c0, 2, c0, 0) #define VMPIDR __ACCESS_CP15(c0, 4, c0, 5) #define SCTLR __ACCESS_CP15(c1, 0, c0, 0) @@ -71,6 +74,11 @@ #define TID_URO __ACCESS_CP15(c13, 0, c0, 3) #define TID_PRIV __ACCESS_CP15(c13, 0, c0, 4) #define CNTKCTL __ACCESS_CP15(c14, 0, c1, 0) +#define CNTV_CTL __ACCESS_CP15(c14, 0, c3, 1) +#define CNTHCTL __ACCESS_CP15(c14, 4, c1, 0) + +void __timer_save_state(struct kvm_vcpu *vcpu); +void __timer_restore_state(struct kvm_vcpu *vcpu); void __sysreg_save_state(struct kvm_cpu_context *ctxt); void __sysreg_restore_state(struct kvm_cpu_context *ctxt); diff --git a/arch/arm/kvm/hyp/timer-sr.c b/arch/arm/kvm/hyp/timer-sr.c new file mode 100644 index 0000000..d7535fd --- /dev/null +++ b/arch/arm/kvm/hyp/timer-sr.c @@ -0,0 +1,71 @@ +/* + * Copyright (C) 2012-2015 - ARM Ltd + * Author: Marc Zyngier + * + * 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 . + */ + +#include +#include +#include + +#include + +#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; + u64 val; + + if (kvm->arch.timer.enabled) { + timer->cntv_ctl = read_sysreg(CNTV_CTL); + timer->cntv_cval = read_sysreg(CNTV_CVAL); + } + + /* Disable the virtual timer */ + write_sysreg(0, CNTV_CTL); + + /* Allow physical timer/counter access for the host */ + val = read_sysreg(CNTHCTL); + val |= CNTHCTL_EL1PCTEN | CNTHCTL_EL1PCEN; + write_sysreg(val, CNTHCTL); + + /* Clear cntvoff for the host */ + write_sysreg(0, CNTVOFF); +} + +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); + val &= ~CNTHCTL_EL1PCEN; + val |= CNTHCTL_EL1PCTEN; + write_sysreg(val, CNTHCTL); + + if (kvm->arch.timer.enabled) { + write_sysreg(kvm->arch.timer.cntvoff, CNTVOFF); + write_sysreg(timer->cntv_cval, CNTV_CVAL); + isb(); + write_sysreg(timer->cntv_ctl, CNTV_CTL); + } +} -- 2.7.4