From: Christoffer Dall <christoffer.d...@arm.com> Emulating the ARMv8.4-NV timers is a bit odd, as the timers can be reconfigured behind our back without the hypervisor even noticing. In the VHE case, that's an actual regression in the architecture...
Signed-off-by: Christoffer Dall <christoffer.d...@arm.com> Signed-off-by: Marc Zyngier <m...@kernel.org> --- include/kvm/arm_arch_timer.h | 3 ++- virt/kvm/arm/arch_timer.c | 41 +++++++++++++++++++++++++++++++++++- virt/kvm/arm/arm.c | 7 ++++-- 3 files changed, 47 insertions(+), 4 deletions(-) diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h index 3389606f3029..2442de2c4a6e 100644 --- a/include/kvm/arm_arch_timer.h +++ b/include/kvm/arm_arch_timer.h @@ -75,7 +75,8 @@ 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_hwstate(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); void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu); diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c index f9ef86752630..b95798f81764 100644 --- a/virt/kvm/arm/arch_timer.c +++ b/virt/kvm/arm/arch_timer.c @@ -710,6 +710,45 @@ void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu) set_cntvoff(0); } +void kvm_timer_sync_nested(struct kvm_vcpu *vcpu) +{ +#ifdef CONFIG_ARM64 + if (!is_hyp_ctxt(vcpu)) + return; + + /* + * Guest hypervisors using ARMv8.4 enhanced nested virt support have + * their EL1 timer register accesses redirected to the VNCR page. + */ + if (!vcpu_el2_e2h_is_set(vcpu)) { + /* + * For a non-VHE guest hypervisor, 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 emulated state (which + * is stored in the VNCR page) 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); + } +#endif +} + /* * 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 @@ -728,7 +767,7 @@ static void unmask_vtimer_irq_user(struct kvm_vcpu *vcpu) } } -void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu) +void kvm_timer_sync_user(struct kvm_vcpu *vcpu) { struct arch_timer_cpu *timer = vcpu_timer(vcpu); diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c index fa73b7a464f1..e8fedbfacc2c 100644 --- a/virt/kvm/arm/arm.c +++ b/virt/kvm/arm/arm.c @@ -730,7 +730,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) isb(); /* Ensure work in x_flush_hwstate is committed */ kvm_pmu_sync_hwstate(vcpu); if (static_branch_unlikely(&userspace_irqchip_in_use)) - kvm_timer_sync_hwstate(vcpu); + kvm_timer_sync_user(vcpu); kvm_vgic_sync_hwstate(vcpu); local_irq_enable(); preempt_enable(); @@ -781,7 +781,10 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) * timer virtual interrupt state. */ if (static_branch_unlikely(&userspace_irqchip_in_use)) - kvm_timer_sync_hwstate(vcpu); + kvm_timer_sync_user(vcpu); + + if (enhanced_nested_virt_in_use(vcpu)) + kvm_timer_sync_nested(vcpu); kvm_arch_vcpu_ctxsync_fp(vcpu); -- 2.20.1 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm