[PATCH v2 10/28] ARM: KVM: Add timer save/restore

Marc Zyngier
2016-02-04T11:00:27Z

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.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
arch/arm/kvm/hyp/Makefile | 1 +
arch/arm/kvm/hyp/hyp.h | 8 +++++
arch/arm/kvm/hyp/timer-sr.c | 71 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 80 insertions(+)
create mode 100644 arch/arm/kvm/hyp/timer-sr.c

diff --git a/arch/arm/kvm/hyp/Makefile b/arch/arm/kvm/hyp/Makefile
index 9f96fcb..9241ae8 100644
--- a/arch/arm/kvm/hyp/Makefile
+++ b/arch/arm/kvm/hyp/Makefile
@@ -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
diff --git a/arch/arm/kvm/hyp/hyp.h b/arch/arm/kvm/hyp/hyp.h
index ab2cb82..4924418 100644
--- a/arch/arm/kvm/hyp/hyp.h
+++ b/arch/arm/kvm/hyp/hyp.h
@@ -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);
diff --git a/arch/arm/kvm/hyp/timer-sr.c b/arch/arm/kvm/hyp/timer-sr.c
new file mode 100644
index 0000000..d7535fd
--- /dev/null
+++ b/arch/arm/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);
+ 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);
+ }
+}
--
2.1.4