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Commit e59bff9b authored by Marc Zyngier's avatar Marc Zyngier
Browse files

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: default avatarChristoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent c7ce6c63

arch/arm/kvm/hyp/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

arch/arm/kvm/hyp/hyp.h

+8 −0
Original line number Diff line number Diff line
@@ -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);

arch/arm/kvm/hyp/timer-sr.c

0 → 100644
+71 −0
Original line number Diff line number Diff line 
/*

 * 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);

	}

}