From bf0cd88ce363a2de3684baaa48d3f194acdc516c Mon Sep 17 00:00:00 2001 From: Yadong Qi Date: Fri, 6 Nov 2020 14:51:22 +0800 Subject: KVM: x86: emulate wait-for-SIPI and SIPI-VMExit Background: We have a lightweight HV, it needs INIT-VMExit and SIPI-VMExit to wake-up APs for guests since it do not monitor the Local APIC. But currently virtual wait-for-SIPI(WFS) state is not supported in nVMX, so when running on top of KVM, the L1 HV cannot receive the INIT-VMExit and SIPI-VMExit which cause the L2 guest cannot wake up the APs. According to Intel SDM Chapter 25.2 Other Causes of VM Exits, SIPIs cause VM exits when a logical processor is in wait-for-SIPI state. In this patch: 1. introduce SIPI exit reason, 2. introduce wait-for-SIPI state for nVMX, 3. advertise wait-for-SIPI support to guest. When L1 hypervisor is not monitoring Local APIC, L0 need to emulate INIT-VMExit and SIPI-VMExit to L1 to emulate INIT-SIPI-SIPI for L2. L2 LAPIC write would be traped by L0 Hypervisor(KVM), L0 should emulate the INIT/SIPI vmexit to L1 hypervisor to set proper state for L2's vcpu state. Handle procdure: Source vCPU: L2 write LAPIC.ICR(INIT). L0 trap LAPIC.ICR write(INIT): inject a latched INIT event to target vCPU. Target vCPU: L0 emulate an INIT VMExit to L1 if is guest mode. L1 set guest VMCS, guest_activity_state=WAIT_SIPI, vmresume. L0 set vcpu.mp_state to INIT_RECEIVED if (vmcs12.guest_activity_state == WAIT_SIPI). Source vCPU: L2 write LAPIC.ICR(SIPI). L0 trap LAPIC.ICR write(INIT): inject a latched SIPI event to traget vCPU. Target vCPU: L0 emulate an SIPI VMExit to L1 if (vcpu.mp_state == INIT_RECEIVED). L1 set CS:IP, guest_activity_state=ACTIVE, vmresume. L0 resume to L2. L2 start-up. Signed-off-by: Yadong Qi Message-Id: <20200922052343.84388-1-yadong.qi@intel.com> Signed-off-by: Paolo Bonzini Message-Id: <20201106065122.403183-1-yadong.qi@intel.com> Signed-off-by: Paolo Bonzini --- arch/x86/include/asm/vmx.h | 1 + arch/x86/include/uapi/asm/vmx.h | 2 ++ arch/x86/kvm/vmx/nested.c | 55 ++++++++++++++++++++++++++++++----------- 3 files changed, 44 insertions(+), 14 deletions(-) diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h index f8ba5289ecb0..38ca445a8429 100644 --- a/arch/x86/include/asm/vmx.h +++ b/arch/x86/include/asm/vmx.h @@ -113,6 +113,7 @@ #define VMX_MISC_PREEMPTION_TIMER_RATE_MASK 0x0000001f #define VMX_MISC_SAVE_EFER_LMA 0x00000020 #define VMX_MISC_ACTIVITY_HLT 0x00000040 +#define VMX_MISC_ACTIVITY_WAIT_SIPI 0x00000100 #define VMX_MISC_ZERO_LEN_INS 0x40000000 #define VMX_MISC_MSR_LIST_MULTIPLIER 512 diff --git a/arch/x86/include/uapi/asm/vmx.h b/arch/x86/include/uapi/asm/vmx.h index b8ff9e8ac0d5..ada955c5ebb6 100644 --- a/arch/x86/include/uapi/asm/vmx.h +++ b/arch/x86/include/uapi/asm/vmx.h @@ -32,6 +32,7 @@ #define EXIT_REASON_EXTERNAL_INTERRUPT 1 #define EXIT_REASON_TRIPLE_FAULT 2 #define EXIT_REASON_INIT_SIGNAL 3 +#define EXIT_REASON_SIPI_SIGNAL 4 #define EXIT_REASON_INTERRUPT_WINDOW 7 #define EXIT_REASON_NMI_WINDOW 8 @@ -94,6 +95,7 @@ { EXIT_REASON_EXTERNAL_INTERRUPT, "EXTERNAL_INTERRUPT" }, \ { EXIT_REASON_TRIPLE_FAULT, "TRIPLE_FAULT" }, \ { EXIT_REASON_INIT_SIGNAL, "INIT_SIGNAL" }, \ + { EXIT_REASON_SIPI_SIGNAL, "SIPI_SIGNAL" }, \ { EXIT_REASON_INTERRUPT_WINDOW, "INTERRUPT_WINDOW" }, \ { EXIT_REASON_NMI_WINDOW, "NMI_WINDOW" }, \ { EXIT_REASON_TASK_SWITCH, "TASK_SWITCH" }, \ diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index efebd849b3c9..e2f26564a12d 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -2952,7 +2952,8 @@ static int nested_vmx_check_vmcs_link_ptr(struct kvm_vcpu *vcpu, static int nested_check_guest_non_reg_state(struct vmcs12 *vmcs12) { if (CC(vmcs12->guest_activity_state != GUEST_ACTIVITY_ACTIVE && - vmcs12->guest_activity_state != GUEST_ACTIVITY_HLT)) + vmcs12->guest_activity_state != GUEST_ACTIVITY_HLT && + vmcs12->guest_activity_state != GUEST_ACTIVITY_WAIT_SIPI)) return -EINVAL; return 0; @@ -3559,19 +3560,29 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch) */ nested_cache_shadow_vmcs12(vcpu, vmcs12); - /* - * If we're entering a halted L2 vcpu and the L2 vcpu won't be - * awakened by event injection or by an NMI-window VM-exit or - * by an interrupt-window VM-exit, halt the vcpu. - */ - if ((vmcs12->guest_activity_state == GUEST_ACTIVITY_HLT) && - !(vmcs12->vm_entry_intr_info_field & INTR_INFO_VALID_MASK) && - !(vmcs12->cpu_based_vm_exec_control & CPU_BASED_NMI_WINDOW_EXITING) && - !((vmcs12->cpu_based_vm_exec_control & CPU_BASED_INTR_WINDOW_EXITING) && - (vmcs12->guest_rflags & X86_EFLAGS_IF))) { + switch (vmcs12->guest_activity_state) { + case GUEST_ACTIVITY_HLT: + /* + * If we're entering a halted L2 vcpu and the L2 vcpu won't be + * awakened by event injection or by an NMI-window VM-exit or + * by an interrupt-window VM-exit, halt the vcpu. + */ + if (!(vmcs12->vm_entry_intr_info_field & INTR_INFO_VALID_MASK) && + !nested_cpu_has(vmcs12, CPU_BASED_NMI_WINDOW_EXITING) && + !(nested_cpu_has(vmcs12, CPU_BASED_INTR_WINDOW_EXITING) && + (vmcs12->guest_rflags & X86_EFLAGS_IF))) { + vmx->nested.nested_run_pending = 0; + return kvm_vcpu_halt(vcpu); + } + break; + case GUEST_ACTIVITY_WAIT_SIPI: vmx->nested.nested_run_pending = 0; - return kvm_vcpu_halt(vcpu); + vcpu->arch.mp_state = KVM_MP_STATE_INIT_RECEIVED; + break; + default: + break; } + return 1; vmentry_failed: @@ -3797,7 +3808,20 @@ static int vmx_check_nested_events(struct kvm_vcpu *vcpu) return -EBUSY; nested_vmx_update_pending_dbg(vcpu); clear_bit(KVM_APIC_INIT, &apic->pending_events); - nested_vmx_vmexit(vcpu, EXIT_REASON_INIT_SIGNAL, 0, 0); + if (vcpu->arch.mp_state != KVM_MP_STATE_INIT_RECEIVED) + nested_vmx_vmexit(vcpu, EXIT_REASON_INIT_SIGNAL, 0, 0); + return 0; + } + + if (lapic_in_kernel(vcpu) && + test_bit(KVM_APIC_SIPI, &apic->pending_events)) { + if (block_nested_events) + return -EBUSY; + + clear_bit(KVM_APIC_SIPI, &apic->pending_events); + if (vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED) + nested_vmx_vmexit(vcpu, EXIT_REASON_SIPI_SIGNAL, 0, + apic->sipi_vector & 0xFFUL); return 0; } @@ -4036,6 +4060,8 @@ static void sync_vmcs02_to_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12) if (vcpu->arch.mp_state == KVM_MP_STATE_HALTED) vmcs12->guest_activity_state = GUEST_ACTIVITY_HLT; + else if (vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED) + vmcs12->guest_activity_state = GUEST_ACTIVITY_WAIT_SIPI; else vmcs12->guest_activity_state = GUEST_ACTIVITY_ACTIVE; @@ -6483,7 +6509,8 @@ void nested_vmx_setup_ctls_msrs(struct nested_vmx_msrs *msrs, u32 ept_caps) msrs->misc_low |= MSR_IA32_VMX_MISC_VMWRITE_SHADOW_RO_FIELDS | VMX_MISC_EMULATED_PREEMPTION_TIMER_RATE | - VMX_MISC_ACTIVITY_HLT; + VMX_MISC_ACTIVITY_HLT | + VMX_MISC_ACTIVITY_WAIT_SIPI; msrs->misc_high = 0; /* -- cgit v1.2.3