From 2c82878b0cb38fd516fd612c67852a6bbf282003 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Mon, 27 Mar 2017 14:37:28 +0200 Subject: [PATCH] KVM: VMX: require virtual NMI support Virtual NMIs are only missing in Prescott and Yonah chips. Both are obsolete for virtualization usage---Yonah is 32-bit only even---so drop vNMI emulation. Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx.c | 143 ++++++++++++--------------------------------- 1 file changed, 38 insertions(+), 105 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index b19055a3106f..40b80e8959e1 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -615,10 +615,6 @@ struct vcpu_vmx { int vpid; bool emulation_required; - /* Support for vnmi-less CPUs */ - int soft_vnmi_blocked; - ktime_t entry_time; - s64 vnmi_blocked_time; u32 exit_reason; /* Posted interrupt descriptor */ @@ -1290,11 +1286,6 @@ static inline bool cpu_has_vmx_invpcid(void) SECONDARY_EXEC_ENABLE_INVPCID; } -static inline bool cpu_has_virtual_nmis(void) -{ - return vmcs_config.pin_based_exec_ctrl & PIN_BASED_VIRTUAL_NMIS; -} - static inline bool cpu_has_vmx_wbinvd_exit(void) { return vmcs_config.cpu_based_2nd_exec_ctrl & @@ -3623,9 +3614,9 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf) &_vmexit_control) < 0) return -EIO; - min = PIN_BASED_EXT_INTR_MASK | PIN_BASED_NMI_EXITING; - opt = PIN_BASED_VIRTUAL_NMIS | PIN_BASED_POSTED_INTR | - PIN_BASED_VMX_PREEMPTION_TIMER; + min = PIN_BASED_EXT_INTR_MASK | PIN_BASED_NMI_EXITING | + PIN_BASED_VIRTUAL_NMIS; + opt = PIN_BASED_POSTED_INTR | PIN_BASED_VMX_PREEMPTION_TIMER; if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_PINBASED_CTLS, &_pin_based_exec_control) < 0) return -EIO; @@ -5298,8 +5289,6 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) vmx->rmode.vm86_active = 0; - vmx->soft_vnmi_blocked = 0; - vmx->vcpu.arch.regs[VCPU_REGS_RDX] = get_rdx_init_val(); kvm_set_cr8(vcpu, 0); @@ -5419,8 +5408,7 @@ static void enable_irq_window(struct kvm_vcpu *vcpu) static void enable_nmi_window(struct kvm_vcpu *vcpu) { - if (!cpu_has_virtual_nmis() || - vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & GUEST_INTR_STATE_STI) { + if (vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & GUEST_INTR_STATE_STI) { enable_irq_window(vcpu); return; } @@ -5461,19 +5449,6 @@ static void vmx_inject_nmi(struct kvm_vcpu *vcpu) struct vcpu_vmx *vmx = to_vmx(vcpu); if (!is_guest_mode(vcpu)) { - if (!cpu_has_virtual_nmis()) { - /* - * Tracking the NMI-blocked state in software is built upon - * finding the next open IRQ window. This, in turn, depends on - * well-behaving guests: They have to keep IRQs disabled at - * least as long as the NMI handler runs. Otherwise we may - * cause NMI nesting, maybe breaking the guest. But as this is - * highly unlikely, we can live with the residual risk. - */ - vmx->soft_vnmi_blocked = 1; - vmx->vnmi_blocked_time = 0; - } - ++vcpu->stat.nmi_injections; vmx->nmi_known_unmasked = false; } @@ -5490,8 +5465,6 @@ static void vmx_inject_nmi(struct kvm_vcpu *vcpu) static bool vmx_get_nmi_mask(struct kvm_vcpu *vcpu) { - if (!cpu_has_virtual_nmis()) - return to_vmx(vcpu)->soft_vnmi_blocked; if (to_vmx(vcpu)->nmi_known_unmasked) return false; return vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & GUEST_INTR_STATE_NMI; @@ -5501,20 +5474,13 @@ static void vmx_set_nmi_mask(struct kvm_vcpu *vcpu, bool masked) { struct vcpu_vmx *vmx = to_vmx(vcpu); - if (!cpu_has_virtual_nmis()) { - if (vmx->soft_vnmi_blocked != masked) { - vmx->soft_vnmi_blocked = masked; - vmx->vnmi_blocked_time = 0; - } - } else { - vmx->nmi_known_unmasked = !masked; - if (masked) - vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO, - GUEST_INTR_STATE_NMI); - else - vmcs_clear_bits(GUEST_INTERRUPTIBILITY_INFO, - GUEST_INTR_STATE_NMI); - } + vmx->nmi_known_unmasked = !masked; + if (masked) + vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO, + GUEST_INTR_STATE_NMI); + else + vmcs_clear_bits(GUEST_INTERRUPTIBILITY_INFO, + GUEST_INTR_STATE_NMI); } static int vmx_nmi_allowed(struct kvm_vcpu *vcpu) @@ -5522,9 +5488,6 @@ static int vmx_nmi_allowed(struct kvm_vcpu *vcpu) if (to_vmx(vcpu)->nested.nested_run_pending) return 0; - if (!cpu_has_virtual_nmis() && to_vmx(vcpu)->soft_vnmi_blocked) - return 0; - return !(vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & (GUEST_INTR_STATE_MOV_SS | GUEST_INTR_STATE_STI | GUEST_INTR_STATE_NMI)); @@ -6269,7 +6232,6 @@ static int handle_ept_violation(struct kvm_vcpu *vcpu) * AAK134, BY25. */ if (!(to_vmx(vcpu)->idt_vectoring_info & VECTORING_INFO_VALID_MASK) && - cpu_has_virtual_nmis() && (exit_qualification & INTR_INFO_UNBLOCK_NMI)) vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO, GUEST_INTR_STATE_NMI); @@ -7820,7 +7782,6 @@ static int handle_pml_full(struct kvm_vcpu *vcpu) * "blocked by NMI" bit has to be set before next VM entry. */ if (!(to_vmx(vcpu)->idt_vectoring_info & VECTORING_INFO_VALID_MASK) && - cpu_has_virtual_nmis() && (exit_qualification & INTR_INFO_UNBLOCK_NMI)) vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO, GUEST_INTR_STATE_NMI); @@ -8492,26 +8453,6 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu) return 0; } - if (unlikely(!cpu_has_virtual_nmis() && vmx->soft_vnmi_blocked && - !(is_guest_mode(vcpu) && nested_cpu_has_virtual_nmis( - get_vmcs12(vcpu))))) { - if (vmx_interrupt_allowed(vcpu)) { - vmx->soft_vnmi_blocked = 0; - } else if (vmx->vnmi_blocked_time > 1000000000LL && - vcpu->arch.nmi_pending) { - /* - * This CPU don't support us in finding the end of an - * NMI-blocked window if the guest runs with IRQs - * disabled. So we pull the trigger after 1 s of - * futile waiting, but inform the user about this. - */ - printk(KERN_WARNING "%s: Breaking out of NMI-blocked " - "state on VCPU %d after 1 s timeout\n", - __func__, vcpu->vcpu_id); - vmx->soft_vnmi_blocked = 0; - } - } - if (exit_reason < kvm_vmx_max_exit_handlers && kvm_vmx_exit_handlers[exit_reason]) return kvm_vmx_exit_handlers[exit_reason](vcpu); @@ -8787,37 +8728,33 @@ static void vmx_recover_nmi_blocking(struct vcpu_vmx *vmx) idtv_info_valid = vmx->idt_vectoring_info & VECTORING_INFO_VALID_MASK; - if (cpu_has_virtual_nmis()) { - if (vmx->nmi_known_unmasked) - return; - /* - * Can't use vmx->exit_intr_info since we're not sure what - * the exit reason is. - */ - exit_intr_info = vmcs_read32(VM_EXIT_INTR_INFO); - unblock_nmi = (exit_intr_info & INTR_INFO_UNBLOCK_NMI) != 0; - vector = exit_intr_info & INTR_INFO_VECTOR_MASK; - /* - * SDM 3: 27.7.1.2 (September 2008) - * Re-set bit "block by NMI" before VM entry if vmexit caused by - * a guest IRET fault. - * SDM 3: 23.2.2 (September 2008) - * Bit 12 is undefined in any of the following cases: - * If the VM exit sets the valid bit in the IDT-vectoring - * information field. - * If the VM exit is due to a double fault. - */ - if ((exit_intr_info & INTR_INFO_VALID_MASK) && unblock_nmi && - vector != DF_VECTOR && !idtv_info_valid) - vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO, - GUEST_INTR_STATE_NMI); - else - vmx->nmi_known_unmasked = - !(vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) - & GUEST_INTR_STATE_NMI); - } else if (unlikely(vmx->soft_vnmi_blocked)) - vmx->vnmi_blocked_time += - ktime_to_ns(ktime_sub(ktime_get(), vmx->entry_time)); + if (vmx->nmi_known_unmasked) + return; + /* + * Can't use vmx->exit_intr_info since we're not sure what + * the exit reason is. + */ + exit_intr_info = vmcs_read32(VM_EXIT_INTR_INFO); + unblock_nmi = (exit_intr_info & INTR_INFO_UNBLOCK_NMI) != 0; + vector = exit_intr_info & INTR_INFO_VECTOR_MASK; + /* + * SDM 3: 27.7.1.2 (September 2008) + * Re-set bit "block by NMI" before VM entry if vmexit caused by + * a guest IRET fault. + * SDM 3: 23.2.2 (September 2008) + * Bit 12 is undefined in any of the following cases: + * If the VM exit sets the valid bit in the IDT-vectoring + * information field. + * If the VM exit is due to a double fault. + */ + if ((exit_intr_info & INTR_INFO_VALID_MASK) && unblock_nmi && + vector != DF_VECTOR && !idtv_info_valid) + vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO, + GUEST_INTR_STATE_NMI); + else + vmx->nmi_known_unmasked = + !(vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) + & GUEST_INTR_STATE_NMI); } static void __vmx_complete_interrupts(struct kvm_vcpu *vcpu, @@ -8934,10 +8871,6 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) struct vcpu_vmx *vmx = to_vmx(vcpu); unsigned long debugctlmsr, cr4; - /* Record the guest's net vcpu time for enforced NMI injections. */ - if (unlikely(!cpu_has_virtual_nmis() && vmx->soft_vnmi_blocked)) - vmx->entry_time = ktime_get(); - /* Don't enter VMX if guest state is invalid, let the exit handler start emulation until we arrive back to a valid state */ if (vmx->emulation_required) -- GitLab