arm64: KVM: Implement timer save/restore

Implement the timer save restore as a direct translation of
the assembly code version.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile
index d1e38ce16bb5d710bae6387ccae880197a1b80e1..455dc0a3acb5616afb168cfcb771f4ad6d223cd2 100644 (file)
--- a/arch/arm64/kvm/hyp/Makefile
+++ b/arch/arm64/kvm/hyp/Makefile
@@ -4,3 +4,4 @@
 
 obj-$(CONFIG_KVM_ARM_HOST) += vgic-v2-sr.o
 obj-$(CONFIG_KVM_ARM_HOST) += vgic-v3-sr.o
+obj-$(CONFIG_KVM_ARM_HOST) += timer-sr.o

diff --git a/arch/arm64/kvm/hyp/hyp.h b/arch/arm64/kvm/hyp/hyp.h
index 5759f9f5ef149323b482beeeb82c9c5f4db9d8c9..f213e4652bbf8ab1871c91a7696446c4044767e0 100644 (file)
--- a/arch/arm64/kvm/hyp/hyp.h
+++ b/arch/arm64/kvm/hyp/hyp.h
@@ -35,5 +35,8 @@ void __vgic_v2_restore_state(struct kvm_vcpu *vcpu);
 void __vgic_v3_save_state(struct kvm_vcpu *vcpu);
 void __vgic_v3_restore_state(struct kvm_vcpu *vcpu);
 
+void __timer_save_state(struct kvm_vcpu *vcpu);
+void __timer_restore_state(struct kvm_vcpu *vcpu);
+
 #endif /* __ARM64_KVM_HYP_H__ */
 

diff --git a/arch/arm64/kvm/hyp/timer-sr.c b/arch/arm64/kvm/hyp/timer-sr.c
new file mode 100644 (file)
index 0000000..1051e5d
--- /dev/null
+++ b/arch/arm64/kvm/hyp/timer-sr.c
@@ -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_el0);
+               timer->cntv_cval = read_sysreg(cntv_cval_el0);
+       }
+
+       /* Disable the virtual timer */
+       write_sysreg(0, cntv_ctl_el0);
+
+       /* Allow physical timer/counter access for the host */
+       val = read_sysreg(cnthctl_el2);
+       val |= CNTHCTL_EL1PCTEN | CNTHCTL_EL1PCEN;
+       write_sysreg(val, cnthctl_el2);
+
+       /* Clear cntvoff for the host */
+       write_sysreg(0, cntvoff_el2);
+}
+
+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_el2);
+       val &= ~CNTHCTL_EL1PCEN;
+       val |= CNTHCTL_EL1PCTEN;
+       write_sysreg(val, cnthctl_el2);
+
+       if (kvm->arch.timer.enabled) {
+               write_sysreg(kvm->arch.timer.cntvoff, cntvoff_el2);
+               write_sysreg(timer->cntv_cval, cntv_cval_el0);
+               isb();
+               write_sysreg(timer->cntv_ctl, cntv_ctl_el0);
+       }
+}

diff --git a/include/clocksource/arm_arch_timer.h b/include/clocksource/arm_arch_timer.h
index 9916d0e4eff505f18cf5e30ad52dbe2e37b3fa3b..25d0914481a26d04a001a91216df6fd68c52e87c 100644 (file)
--- a/include/clocksource/arm_arch_timer.h
+++ b/include/clocksource/arm_arch_timer.h
@@ -23,6 +23,12 @@
 #define ARCH_TIMER_CTRL_IT_MASK                (1 << 1)
 #define ARCH_TIMER_CTRL_IT_STAT                (1 << 2)
 
+#define CNTHCTL_EL1PCTEN               (1 << 0)
+#define CNTHCTL_EL1PCEN                        (1 << 1)
+#define CNTHCTL_EVNTEN                 (1 << 2)
+#define CNTHCTL_EVNTDIR                        (1 << 3)
+#define CNTHCTL_EVNTI                  (0xF << 4)
+
 enum arch_timer_reg {
        ARCH_TIMER_REG_CTRL,
        ARCH_TIMER_REG_TVAL,