@@ -821,6 +821,50 @@ void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu)
kvm_timer_blocking(vcpu);
}
+void kvm_timer_sync_nested(struct kvm_vcpu *vcpu)
+{
+ /*
+ * When NV2 is on, guest hypervisors have their EL0 timer register
+ * accesses redirected to the VNCR page. Any guest action taken on
+ * the timer is postponed until the next exit, leading to a very
+ * poor quality of emulation.
+ */
+ if (!is_hyp_ctxt(vcpu))
+ return;
+
+ if (!vcpu_el2_e2h_is_set(vcpu)) {
+ /*
+ * A non-VHE guest hypervisor doesn't have any direct access
+ * to its timers: the EL2 registers trap (and the HW is
+ * fully emulated), while the EL0 registers access memory
+ * despite the access being notionally direct. Boo.
+ *
+ * We update the hardware timer registers with the
+ * latest value written by the guest to the VNCR page
+ * and let the hardware take care of the rest.
+ */
+ write_sysreg_el0(__vcpu_sys_reg(vcpu, CNTV_CTL_EL0), SYS_CNTV_CTL);
+ write_sysreg_el0(__vcpu_sys_reg(vcpu, CNTV_CVAL_EL0), SYS_CNTV_CVAL);
+ write_sysreg_el0(__vcpu_sys_reg(vcpu, CNTP_CTL_EL0), SYS_CNTP_CTL);
+ write_sysreg_el0(__vcpu_sys_reg(vcpu, CNTP_CVAL_EL0), SYS_CNTP_CVAL);
+ } else {
+ /*
+ * For a VHE guest hypervisor, the EL2 state is directly
+ * stored in the host EL0 timers, while the emulated EL0
+ * state is stored in the VNCR page. The latter could have
+ * been updated behind our back, and we must reset the
+ * emulation of the timers.
+ */
+ struct timer_map map;
+ get_timer_map(vcpu, &map);
+
+ soft_timer_cancel(&map.emul_vtimer->hrtimer);
+ soft_timer_cancel(&map.emul_ptimer->hrtimer);
+ timer_emulate(map.emul_vtimer);
+ timer_emulate(map.emul_ptimer);
+ }
+}
+
/*
* With a userspace irqchip we have to check if the guest de-asserted the
* timer and if so, unmask the timer irq signal on the host interrupt
@@ -992,6 +992,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
if (static_branch_unlikely(&userspace_irqchip_in_use))
kvm_timer_sync_user(vcpu);
+ if (vcpu_has_nv2(vcpu))
+ kvm_timer_sync_nested(vcpu);
+
kvm_arch_vcpu_ctxsync_fp(vcpu);
/*
@@ -68,6 +68,7 @@ int kvm_timer_hyp_init(bool);
int kvm_timer_enable(struct kvm_vcpu *vcpu);
int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu);
void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu);
+void kvm_timer_sync_nested(struct kvm_vcpu *vcpu);
void kvm_timer_sync_user(struct kvm_vcpu *vcpu);
bool kvm_timer_should_notify_user(struct kvm_vcpu *vcpu);
void kvm_timer_update_run(struct kvm_vcpu *vcpu);