Add support for the in-kernel timer emulation.
Reviewed-by: Christopher Covington <cov@xxxxxxxxxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
arch/arm64/kvm/hyp.S | 56 +++++++++++++++++++++++++++++++++++++++++++++++
virt/kvm/arm/arch_timer.c | 1 +
2 files changed, 57 insertions(+)
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index 06a69af4..926dc7e 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -390,6 +390,60 @@ __kvm_hyp_code_start:
2:
.endm
+.macro save_timer_state
+ // x0: vcpu pointer
+ ldr x2, [x0, #VCPU_KVM]
+ kern_hyp_va x2
+ ldr w3, [x2, #KVM_TIMER_ENABLED]
+ cbz w3, 1f
+
+ mrs x3, cntv_ctl_el0
+ and x3, x3, #3
+ str w3, [x0, #VCPU_TIMER_CNTV_CTL]
+ bic x3, x3, #1 // Clear Enable
+ msr cntv_ctl_el0, x3
+
+ isb
+
+ mrs x3, cntv_cval_el0
+ str x3, [x0, #VCPU_TIMER_CNTV_CVAL]
+
+1:
+ // Allow physical timer/counter access for the host
+ mrs x2, cnthctl_el2
+ orr x2, x2, #3
+ msr cnthctl_el2, x2
+
+ // Clear cntvoff for the host
+ msr cntvoff_el2, xzr
+.endm
+
+.macro restore_timer_state
+ // x0: vcpu pointer
+ // Disallow physical timer access for the guest
+ // Physical counter access is allowed
+ mrs x2, cnthctl_el2
+ orr x2, x2, #1
+ bic x2, x2, #2
+ msr cnthctl_el2, x2
+
+ ldr x2, [x0, #VCPU_KVM]
+ kern_hyp_va x2
+ ldr w3, [x2, #KVM_TIMER_ENABLED]
+ cbz w3, 1f
+
+ ldr x3, [x2, #KVM_TIMER_CNTVOFF]
+ msr cntvoff_el2, x3
+ ldr x2, [x0, #VCPU_TIMER_CNTV_CVAL]
+ msr cntv_cval_el0, x2
+ isb
+
+ ldr w2, [x0, #VCPU_TIMER_CNTV_CTL]
+ and x2, x2, #3
+ msr cntv_ctl_el0, x2
+1:
+.endm
+
__save_sysregs:
save_sysregs
ret
@@ -433,6 +487,7 @@ ENTRY(__kvm_vcpu_run)
activate_vm
restore_vgic_state
+ restore_timer_state
// Guest context
add x2, x0, #VCPU_CONTEXT
@@ -456,6 +511,7 @@ __kvm_vcpu_return:
bl __save_fpsimd
bl __save_sysregs
+ save_timer_state
save_vgic_state
deactivate_traps
diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
index 2d00b29..6f485ea 100644
--- a/virt/kvm/arm/arch_timer.c
+++ b/virt/kvm/arm/arch_timer.c
@@ -195,6 +195,7 @@ static struct notifier_block kvm_timer_cpu_nb = {
static const struct of_device_id arch_timer_of_match[] = {
{ .compatible = "arm,armv7-timer", },
+ { .compatible = "arm,armv8-timer", },
{},
};
--
1.8.2.3
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