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 arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
  28         u64 val;
  29
  30         if (timer->enabled) {
  31                 timer->cntv_ctl = read_sysreg_el0(cntv_ctl);
  32                 timer->cntv_cval = read_sysreg_el0(cntv_cval);
  33         }
  34
  35         /* Disable the virtual timer */
  36         write_sysreg_el0(0, cntv_ctl);
  37
  38         /*
  39          * We don't need to do this for VHE since the host kernel runs in EL2
  40          * with HCR_EL2.TGE ==1, which makes those bits have no impact.
  41          */
  42         if (!has_vhe()) {
  43                 /* Allow physical timer/counter access for the host */
  44                 val = read_sysreg(cnthctl_el2);
  45                 val |= CNTHCTL_EL1PCTEN | CNTHCTL_EL1PCEN;
  46                 write_sysreg(val, cnthctl_el2);
  47         }
  48
  49         /* Clear cntvoff for the host */
  50         write_sysreg(0, cntvoff_el2);
  51 }
  52
  53 void __hyp_text __timer_restore_state(struct kvm_vcpu *vcpu)
  54 {
  55         struct kvm *kvm = kern_hyp_va(vcpu->kvm);
  56         struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
  57         u64 val;
  58
  59         /* Those bits are already configured at boot on VHE-system */
  60         if (!has_vhe()) {
  61                 /*
  62                  * Disallow physical timer access for the guest
  63                  * Physical counter access is allowed
  64                  */
  65                 val = read_sysreg(cnthctl_el2);
  66                 val &= ~CNTHCTL_EL1PCEN;
  67                 val |= CNTHCTL_EL1PCTEN;
  68                 write_sysreg(val, cnthctl_el2);
  69         }
  70
  71         if (timer->enabled) {
  72                 write_sysreg(kvm->arch.timer.cntvoff, cntvoff_el2);
  73                 write_sysreg_el0(timer->cntv_cval, cntv_cval);
  74                 isb();
  75                 write_sysreg_el0(timer->cntv_ctl, cntv_ctl);
  76         }
  77 }