From b42b4a1b960105bb643de2f7f6f083694ef8f353 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Fabian=20Gr=C3=BCnbichler?= Date: Mon, 4 Dec 2017 09:26:27 +0100 Subject: [PATCH] cherry-pick KVM fix for old CPUs --- ...e-support-for-CPUs-without-virtual-N.patch | 300 ++++++++++++++++++ 1 file changed, 300 insertions(+) create mode 100644 patches/kernel/0013-kvm-vmx-Reinstate-support-for-CPUs-without-virtual-N.patch diff --git a/patches/kernel/0013-kvm-vmx-Reinstate-support-for-CPUs-without-virtual-N.patch b/patches/kernel/0013-kvm-vmx-Reinstate-support-for-CPUs-without-virtual-N.patch new file mode 100644 index 0000000..d8cda5d --- /dev/null +++ b/patches/kernel/0013-kvm-vmx-Reinstate-support-for-CPUs-without-virtual-N.patch @@ -0,0 +1,300 @@ +From 6c42032f6917937fd440a6c21fe28781088aae5a Mon Sep 17 00:00:00 2001 +From: Paolo Bonzini +Date: Mon, 6 Nov 2017 13:31:12 +0100 +Subject: [PATCH 13/13] kvm: vmx: Reinstate support for CPUs without virtual + NMI +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +commit 8a1b43922d0d1279e7936ba85c4c2a870403c95f upstream. + +This is more or less a revert of commit 2c82878b0cb3 ("KVM: VMX: require +virtual NMI support", 2017-03-27); it turns out that Core 2 Duo machines +only had virtual NMIs in some SKUs. + +The revert is not trivial because in the meanwhile there have been several +fixes to nested NMI injection. Therefore, the entire vNMI state is moved +to struct loaded_vmcs. + +Another change compared to before the patch is a simplification here: + + if (unlikely(!cpu_has_virtual_nmis() && vmx->soft_vnmi_blocked && + !(is_guest_mode(vcpu) && nested_cpu_has_virtual_nmis( + get_vmcs12(vcpu))))) { + +The final condition here is always true (because nested_cpu_has_virtual_nmis +is always false) and is removed. + +Fixes: 2c82878b0cb38fd516fd612c67852a6bbf282003 +Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1490803 +Signed-off-by: Paolo Bonzini +Signed-off-by: Radim Krčmář +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Fabian Grünbichler +--- + arch/x86/kvm/vmx.c | 150 +++++++++++++++++++++++++++++++++++++---------------- + 1 file changed, 106 insertions(+), 44 deletions(-) + +diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c +index 118709e7597d..a2c95522ac99 100644 +--- a/arch/x86/kvm/vmx.c ++++ b/arch/x86/kvm/vmx.c +@@ -202,6 +202,10 @@ struct loaded_vmcs { + bool nmi_known_unmasked; + unsigned long vmcs_host_cr3; /* May not match real cr3 */ + unsigned long vmcs_host_cr4; /* May not match real cr4 */ ++ /* Support for vnmi-less CPUs */ ++ int soft_vnmi_blocked; ++ ktime_t entry_time; ++ s64 vnmi_blocked_time; + struct list_head loaded_vmcss_on_cpu_link; + }; + +@@ -1288,6 +1292,11 @@ 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 & +@@ -1339,11 +1348,6 @@ static inline bool nested_cpu_has2(struct vmcs12 *vmcs12, u32 bit) + (vmcs12->secondary_vm_exec_control & bit); + } + +-static inline bool nested_cpu_has_virtual_nmis(struct vmcs12 *vmcs12) +-{ +- return vmcs12->pin_based_vm_exec_control & PIN_BASED_VIRTUAL_NMIS; +-} +- + static inline bool nested_cpu_has_preemption_timer(struct vmcs12 *vmcs12) + { + return vmcs12->pin_based_vm_exec_control & +@@ -3676,9 +3680,9 @@ 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 | +- PIN_BASED_VIRTUAL_NMIS; +- opt = PIN_BASED_POSTED_INTR | PIN_BASED_VMX_PREEMPTION_TIMER; ++ min = PIN_BASED_EXT_INTR_MASK | PIN_BASED_NMI_EXITING; ++ opt = PIN_BASED_VIRTUAL_NMIS | 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; +@@ -5538,7 +5542,8 @@ static void enable_irq_window(struct kvm_vcpu *vcpu) + + static void enable_nmi_window(struct kvm_vcpu *vcpu) + { +- if (vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & GUEST_INTR_STATE_STI) { ++ if (!cpu_has_virtual_nmis() || ++ vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & GUEST_INTR_STATE_STI) { + enable_irq_window(vcpu); + return; + } +@@ -5578,6 +5583,19 @@ static void vmx_inject_nmi(struct kvm_vcpu *vcpu) + { + struct vcpu_vmx *vmx = to_vmx(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->loaded_vmcs->soft_vnmi_blocked = 1; ++ vmx->loaded_vmcs->vnmi_blocked_time = 0; ++ } ++ + ++vcpu->stat.nmi_injections; + vmx->loaded_vmcs->nmi_known_unmasked = false; + +@@ -5596,6 +5614,8 @@ static bool vmx_get_nmi_mask(struct kvm_vcpu *vcpu) + struct vcpu_vmx *vmx = to_vmx(vcpu); + bool masked; + ++ if (!cpu_has_virtual_nmis()) ++ return vmx->loaded_vmcs->soft_vnmi_blocked; + if (vmx->loaded_vmcs->nmi_known_unmasked) + return false; + masked = vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & GUEST_INTR_STATE_NMI; +@@ -5607,13 +5627,20 @@ static void vmx_set_nmi_mask(struct kvm_vcpu *vcpu, bool masked) + { + struct vcpu_vmx *vmx = to_vmx(vcpu); + +- vmx->loaded_vmcs->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); ++ if (!cpu_has_virtual_nmis()) { ++ if (vmx->loaded_vmcs->soft_vnmi_blocked != masked) { ++ vmx->loaded_vmcs->soft_vnmi_blocked = masked; ++ vmx->loaded_vmcs->vnmi_blocked_time = 0; ++ } ++ } else { ++ vmx->loaded_vmcs->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) +@@ -5621,6 +5648,10 @@ 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)->loaded_vmcs->soft_vnmi_blocked) ++ return 0; ++ + return !(vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & + (GUEST_INTR_STATE_MOV_SS | GUEST_INTR_STATE_STI + | GUEST_INTR_STATE_NMI)); +@@ -6348,6 +6379,7 @@ 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); + +@@ -6820,7 +6852,7 @@ static struct loaded_vmcs *nested_get_current_vmcs02(struct vcpu_vmx *vmx) + } + + /* Create a new VMCS */ +- item = kmalloc(sizeof(struct vmcs02_list), GFP_KERNEL); ++ item = kzalloc(sizeof(struct vmcs02_list), GFP_KERNEL); + if (!item) + return NULL; + item->vmcs02.vmcs = alloc_vmcs(); +@@ -7837,6 +7869,7 @@ 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); +@@ -8554,6 +8587,25 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu) + return 0; + } + ++ if (unlikely(!cpu_has_virtual_nmis() && ++ vmx->loaded_vmcs->soft_vnmi_blocked)) { ++ if (vmx_interrupt_allowed(vcpu)) { ++ vmx->loaded_vmcs->soft_vnmi_blocked = 0; ++ } else if (vmx->loaded_vmcs->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->loaded_vmcs->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); +@@ -8837,33 +8889,38 @@ static void vmx_recover_nmi_blocking(struct vcpu_vmx *vmx) + + idtv_info_valid = vmx->idt_vectoring_info & VECTORING_INFO_VALID_MASK; + +- if (vmx->loaded_vmcs->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->loaded_vmcs->nmi_known_unmasked = +- !(vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) +- & GUEST_INTR_STATE_NMI); ++ if (cpu_has_virtual_nmis()) { ++ if (vmx->loaded_vmcs->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->loaded_vmcs->nmi_known_unmasked = ++ !(vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) ++ & GUEST_INTR_STATE_NMI); ++ } else if (unlikely(vmx->loaded_vmcs->soft_vnmi_blocked)) ++ vmx->loaded_vmcs->vnmi_blocked_time += ++ ktime_to_ns(ktime_sub(ktime_get(), ++ vmx->loaded_vmcs->entry_time)); + } + + static void __vmx_complete_interrupts(struct kvm_vcpu *vcpu, +@@ -8980,6 +9037,11 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) + struct vcpu_vmx *vmx = to_vmx(vcpu); + unsigned long debugctlmsr, cr3, cr4; + ++ /* Record the guest's net vcpu time for enforced NMI injections. */ ++ if (unlikely(!cpu_has_virtual_nmis() && ++ vmx->loaded_vmcs->soft_vnmi_blocked)) ++ vmx->loaded_vmcs->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) +-- +2.14.2 +