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ARM: KVM: Add timer save/restore

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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 <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
Marc Zyngier 2016-01-04 08:54:50 +00:00
parent c7ce6c63a0
commit e59bff9bf3
3 changed files with 80 additions and 0 deletions
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1
arch/arm/kvm/hyp/Makefile
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@ -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

8
arch/arm/kvm/hyp/hyp.h
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@ -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);

71
arch/arm/kvm/hyp/timer-sr.c Normal file
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@ -0,0 +1,71 @@
/*
* Copyright (C) 2012-2015 - ARM Ltd
* Author: Marc Zyngier <marc.zyngier@arm.com>
*
* 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;
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);
}
}