From: Jan Kiszka Date: Sun, 28 Apr 2013 08:50:52 +0000 (+0200) Subject: KVM: x86: Rework request for immediate exit X-Git-Tag: firefly_0821_release~3680^2~569^2~14 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=730dca42c1d363c939da18c1499c7327c66e2b37;p=firefly-linux-kernel-4.4.55.git KVM: x86: Rework request for immediate exit The VMX implementation of enable_irq_window raised KVM_REQ_IMMEDIATE_EXIT after we checked it in vcpu_enter_guest. This caused infinite loops on vmentry. Fix it by letting enable_irq_window signal the need for an immediate exit via its return value and drop KVM_REQ_IMMEDIATE_EXIT. This issue only affects nested VMX scenarios. Signed-off-by: Jan Kiszka Signed-off-by: Gleb Natapov --- diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 18635ae42a8e..111b4a0c3907 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -694,7 +694,7 @@ struct kvm_x86_ops { bool (*get_nmi_mask)(struct kvm_vcpu *vcpu); void (*set_nmi_mask)(struct kvm_vcpu *vcpu, bool masked); void (*enable_nmi_window)(struct kvm_vcpu *vcpu); - void (*enable_irq_window)(struct kvm_vcpu *vcpu); + int (*enable_irq_window)(struct kvm_vcpu *vcpu); void (*update_cr8_intercept)(struct kvm_vcpu *vcpu, int tpr, int irr); int (*vm_has_apicv)(struct kvm *kvm); void (*hwapic_irr_update)(struct kvm_vcpu *vcpu, int max_irr); diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 15c9cccd716b..7f896cbe717f 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -3632,7 +3632,7 @@ static int svm_interrupt_allowed(struct kvm_vcpu *vcpu) return ret; } -static void enable_irq_window(struct kvm_vcpu *vcpu) +static int enable_irq_window(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu); @@ -3646,6 +3646,7 @@ static void enable_irq_window(struct kvm_vcpu *vcpu) svm_set_vintr(svm); svm_inject_irq(svm, 0x0); } + return 0; } static void enable_nmi_window(struct kvm_vcpu *vcpu) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 0f0cb3110626..74c525e2c608 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -4398,22 +4398,23 @@ static bool nested_exit_on_nmi(struct kvm_vcpu *vcpu) PIN_BASED_NMI_EXITING; } -static void enable_irq_window(struct kvm_vcpu *vcpu) +static int enable_irq_window(struct kvm_vcpu *vcpu) { u32 cpu_based_vm_exec_control; - if (is_guest_mode(vcpu) && nested_exit_on_intr(vcpu)) { + + if (is_guest_mode(vcpu) && nested_exit_on_intr(vcpu)) /* * We get here if vmx_interrupt_allowed() said we can't - * inject to L1 now because L2 must run. Ask L2 to exit - * right after entry, so we can inject to L1 more promptly. + * inject to L1 now because L2 must run. The caller will have + * to make L2 exit right after entry, so we can inject to L1 + * more promptly. */ - kvm_make_request(KVM_REQ_IMMEDIATE_EXIT, vcpu); - return; - } + return -EBUSY; cpu_based_vm_exec_control = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL); cpu_based_vm_exec_control |= CPU_BASED_VIRTUAL_INTR_PENDING; vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control); + return 0; } static void enable_nmi_window(struct kvm_vcpu *vcpu) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 2a434bf3918d..c522260b5bbf 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5692,7 +5692,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) int r; bool req_int_win = !irqchip_in_kernel(vcpu->kvm) && vcpu->run->request_interrupt_window; - bool req_immediate_exit = 0; + bool req_immediate_exit = false; if (vcpu->requests) { if (kvm_check_request(KVM_REQ_MMU_RELOAD, vcpu)) @@ -5734,8 +5734,6 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) record_steal_time(vcpu); if (kvm_check_request(KVM_REQ_NMI, vcpu)) process_nmi(vcpu); - req_immediate_exit = - kvm_check_request(KVM_REQ_IMMEDIATE_EXIT, vcpu); if (kvm_check_request(KVM_REQ_PMU, vcpu)) kvm_handle_pmu_event(vcpu); if (kvm_check_request(KVM_REQ_PMI, vcpu)) @@ -5757,7 +5755,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) if (vcpu->arch.nmi_pending) kvm_x86_ops->enable_nmi_window(vcpu); else if (kvm_cpu_has_injectable_intr(vcpu) || req_int_win) - kvm_x86_ops->enable_irq_window(vcpu); + req_immediate_exit = + kvm_x86_ops->enable_irq_window(vcpu) != 0; if (kvm_lapic_enabled(vcpu)) { /* diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 93a50054d46c..7bde42470e37 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -119,14 +119,13 @@ static inline bool is_error_page(struct page *page) #define KVM_REQ_APF_HALT 12 #define KVM_REQ_STEAL_UPDATE 13 #define KVM_REQ_NMI 14 -#define KVM_REQ_IMMEDIATE_EXIT 15 -#define KVM_REQ_PMU 16 -#define KVM_REQ_PMI 17 -#define KVM_REQ_WATCHDOG 18 -#define KVM_REQ_MASTERCLOCK_UPDATE 19 -#define KVM_REQ_MCLOCK_INPROGRESS 20 -#define KVM_REQ_EPR_EXIT 21 -#define KVM_REQ_SCAN_IOAPIC 22 +#define KVM_REQ_PMU 15 +#define KVM_REQ_PMI 16 +#define KVM_REQ_WATCHDOG 17 +#define KVM_REQ_MASTERCLOCK_UPDATE 18 +#define KVM_REQ_MCLOCK_INPROGRESS 19 +#define KVM_REQ_EPR_EXIT 20 +#define KVM_REQ_SCAN_IOAPIC 21 #define KVM_USERSPACE_IRQ_SOURCE_ID 0 #define KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID 1