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

   1 /*
   2  * Copyright (C) 2012-2015 - ARM Ltd
   3  * Author: Marc Zyngier <marc.zyngier@arm.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include <clocksource/arm_arch_timer.h>
  19 #include <linux/compiler.h>
  20 #include <linux/kvm_host.h>
  21
  22 #include <asm/kvm_hyp.h>
  23
  24 /* vcpu is already in the HYP VA space */
  25 void __hyp_text __timer_save_state(struct kvm_vcpu *vcpu)
  26 {
  27         struct kvm *kvm = kern_hyp_va(vcpu->kvm);
  28         struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
  29         u64 val;
  30
  31         if (kvm->arch.timer.enabled) {
  32                 timer->cntv_ctl = read_sysreg_el0(cntv_ctl);
  33                 timer->cntv_cval = read_sysreg_el0(cntv_cval);
  34         }
  35
  36         /* Disable the virtual timer */
  37         write_sysreg_el0(0, cntv_ctl);
  38
  39         /* Allow physical timer/counter access for the host */
  40         val = read_sysreg(cnthctl_el2);
  41         val |= CNTHCTL_EL1PCTEN | CNTHCTL_EL1PCEN;
  42         write_sysreg(val, cnthctl_el2);
  43
  44         /* Clear cntvoff for the host */
  45         write_sysreg(0, cntvoff_el2);
  46 }
  47
  48 void __hyp_text __timer_restore_state(struct kvm_vcpu *vcpu)
  49 {
  50         struct kvm *kvm = kern_hyp_va(vcpu->kvm);
  51         struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
  52         u64 val;
  53
  54         /*
  55          * Disallow physical timer access for the guest
  56          * Physical counter access is allowed
  57          */
  58         val = read_sysreg(cnthctl_el2);
  59         val &= ~CNTHCTL_EL1PCEN;
  60         val |= CNTHCTL_EL1PCTEN;
  61         write_sysreg(val, cnthctl_el2);
  62
  63         if (kvm->arch.timer.enabled) {
  64                 write_sysreg(kvm->arch.timer.cntvoff, cntvoff_el2);
  65                 write_sysreg_el0(timer->cntv_cval, cntv_cval);
  66                 isb();
  67                 write_sysreg_el0(timer->cntv_ctl, cntv_ctl);
  68         }
  69 }