[PATCH v4 62/66] KVM: arm64: nv: Sync nested timer state with ARMv8.4
From: Marc Zyngier <maz@kernel.org>
Date: 2021-05-10 17:35:51
Also in:
kvm, kvmarm
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
From: Christoffer Dall <redacted> 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 <redacted> Signed-off-by: Marc Zyngier <maz@kernel.org> --- arch/arm64/kvm/arch_timer.c | 37 ++++++++++++++++++++++++++++++++++++ arch/arm64/kvm/arm.c | 3 +++ include/kvm/arm_arch_timer.h | 1 + 3 files changed, 41 insertions(+)
diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index 8a4fce4ec7d8..c0064168b38d 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c@@ -778,6 +778,43 @@ void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu) set_cntvoff(0); } +void kvm_timer_sync_nested(struct kvm_vcpu *vcpu) +{ + 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); + } +} + /* * 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
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 2e4d74caa114..4d9b3a9e21fd 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c@@ -858,6 +858,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) if (static_branch_unlikely(&userspace_irqchip_in_use)) kvm_timer_sync_user(vcpu); + if (enhanced_nested_virt_in_use(vcpu)) + kvm_timer_sync_nested(vcpu); + kvm_arch_vcpu_ctxsync_fp(vcpu); /*
diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h
index 063f613fbc7e..2e20916e9025 100644
--- a/include/kvm/arm_arch_timer.h
+++ b/include/kvm/arm_arch_timer.h@@ -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);
--
2.29.2
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