From: Nicușor Cîțu <[email protected]> This commit also ensures that the introspection tool and the userspace do not disable each other the CR3-write VM-exit.
Signed-off-by: Nicușor Cîțu <[email protected]> Signed-off-by: Adalbert Lazăr <[email protected]> --- arch/x86/include/asm/kvmi_host.h | 4 ++ arch/x86/kvm/kvmi.c | 64 ++++++++++++++++++++++++++++++-- arch/x86/kvm/svm.c | 5 +++ arch/x86/kvm/vmx/vmx.c | 5 +++ 4 files changed, 75 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/kvmi_host.h b/arch/x86/include/asm/kvmi_host.h index 4ac209cb4ebf..24f3f8fdee62 100644 --- a/arch/x86/include/asm/kvmi_host.h +++ b/arch/x86/include/asm/kvmi_host.h @@ -13,6 +13,7 @@ struct kvmi_monitor_interception { struct kvmi_interception { bool restore_interception; struct kvmi_monitor_interception breakpoint; + struct kvmi_monitor_interception cr3w; }; struct kvm_vcpu_arch_introspection { @@ -28,6 +29,7 @@ bool kvmi_monitor_bp_intercept(struct kvm_vcpu *vcpu, u32 dbg); bool kvmi_cr_event(struct kvm_vcpu *vcpu, unsigned int cr, unsigned long old_value, unsigned long *new_value); bool kvmi_cr3_intercepted(struct kvm_vcpu *vcpu); +bool kvmi_monitor_cr3w_intercept(struct kvm_vcpu *vcpu, bool enable); #else /* CONFIG_KVM_INTROSPECTION */ @@ -37,6 +39,8 @@ static inline bool kvmi_cr_event(struct kvm_vcpu *vcpu, unsigned int cr, unsigned long old_value, unsigned long *new_value) { return true; } static inline bool kvmi_cr3_intercepted(struct kvm_vcpu *vcpu) { return false; } +static inline bool kvmi_monitor_cr3w_intercept(struct kvm_vcpu *vcpu, + bool enable) { return false; } #endif /* CONFIG_KVM_INTROSPECTION */ diff --git a/arch/x86/kvm/kvmi.c b/arch/x86/kvm/kvmi.c index 2e00f0c530f2..281ebb47eaa2 100644 --- a/arch/x86/kvm/kvmi.c +++ b/arch/x86/kvm/kvmi.c @@ -307,6 +307,59 @@ static void kvmi_arch_disable_bp_intercept(struct kvm_vcpu *vcpu) vcpu->arch.kvmi->breakpoint.kvm_intercepted = false; } +static bool monitor_cr3w_fct_kvmi(struct kvm_vcpu *vcpu, bool enable) +{ + vcpu->arch.kvmi->cr3w.kvmi_intercepted = enable; + + if (enable) + vcpu->arch.kvmi->cr3w.kvm_intercepted = + kvm_x86_ops->cr3_write_intercepted(vcpu); + else if (vcpu->arch.kvmi->cr3w.kvm_intercepted) + return true; + + return false; +} + +static bool monitor_cr3w_fct_kvm(struct kvm_vcpu *vcpu, bool enable) +{ + if (!vcpu->arch.kvmi->cr3w.kvmi_intercepted) + return false; + + vcpu->arch.kvmi->cr3w.kvm_intercepted = enable; + + if (!enable) + return true; + + return false; +} + +/* + * Returns true if one side (kvm or kvmi) tries to disable the CR3 write + * interception while the other side is still tracking it. + */ +bool kvmi_monitor_cr3w_intercept(struct kvm_vcpu *vcpu, bool enable) +{ + struct kvmi_interception *arch_vcpui = READ_ONCE(vcpu->arch.kvmi); + + return (arch_vcpui && arch_vcpui->cr3w.monitor_fct(vcpu, enable)); +} +EXPORT_SYMBOL(kvmi_monitor_cr3w_intercept); + +static void kvmi_control_cr3w_intercept(struct kvm_vcpu *vcpu, bool enable) +{ + vcpu->arch.kvmi->cr3w.monitor_fct = monitor_cr3w_fct_kvmi; + kvm_x86_ops->control_cr3_intercept(vcpu, CR_TYPE_W, enable); + vcpu->arch.kvmi->cr3w.monitor_fct = monitor_cr3w_fct_kvm; +} + +static void kvmi_arch_disable_cr3w_intercept(struct kvm_vcpu *vcpu) +{ + kvmi_control_cr3w_intercept(vcpu, false); + + vcpu->arch.kvmi->cr3w.kvmi_intercepted = false; + vcpu->arch.kvmi->cr3w.kvm_intercepted = false; +} + int kvmi_arch_cmd_control_intercept(struct kvm_vcpu *vcpu, unsigned int event_id, bool enable) { @@ -351,6 +404,7 @@ bool kvmi_arch_restore_interception(struct kvm_vcpu *vcpu) return false; kvmi_arch_disable_bp_intercept(vcpu); + kvmi_arch_disable_cr3w_intercept(vcpu); return true; } @@ -364,8 +418,13 @@ bool kvmi_arch_vcpu_alloc(struct kvm_vcpu *vcpu) return false; arch_vcpui->breakpoint.monitor_fct = monitor_bp_fct_kvm; + arch_vcpui->cr3w.monitor_fct = monitor_cr3w_fct_kvm; - /* pair with kvmi_monitor_bp_intercept() */ + /* + * paired with: + * - kvmi_monitor_bp_intercept() + * - kvmi_monitor_cr3w_intercept() + */ smp_wmb(); WRITE_ONCE(vcpu->arch.kvmi, arch_vcpui); @@ -403,8 +462,7 @@ int kvmi_arch_cmd_vcpu_control_cr(struct kvm_vcpu *vcpu, case 0: break; case 3: - kvm_x86_ops->control_cr3_intercept(vcpu, CR_TYPE_W, - req->enable == 1); + kvmi_control_cr3w_intercept(vcpu, req->enable == 1); break; case 4: break; diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 05c64318a8df..1021ff2f9e57 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -7497,6 +7497,11 @@ static void svm_control_cr3_intercept(struct kvm_vcpu *vcpu, int type, { struct vcpu_svm *svm = to_svm(vcpu); +#ifdef CONFIG_KVM_INTROSPECTION + if ((type & CR_TYPE_W) && kvmi_monitor_cr3w_intercept(vcpu, enable)) + type &= ~CR_TYPE_W; +#endif /* CONFIG_KVM_INTROSPECTION */ + if (type & CR_TYPE_R) enable ? set_cr_intercept(svm, INTERCEPT_CR3_READ) : clr_cr_intercept(svm, INTERCEPT_CR3_READ); diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index ff705b4eee19..f6180ecf15ba 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -2940,6 +2940,11 @@ static void vmx_control_cr3_intercept(struct kvm_vcpu *vcpu, int type, struct vcpu_vmx *vmx = to_vmx(vcpu); u32 cr3_exec_control = 0; +#ifdef CONFIG_KVM_INTROSPECTION + if ((type & CR_TYPE_W) && kvmi_monitor_cr3w_intercept(vcpu, enable)) + type &= ~CR_TYPE_W; +#endif /* CONFIG_KVM_INTROSPECTION */ + if (type & CR_TYPE_R) cr3_exec_control |= CPU_BASED_CR3_STORE_EXITING; if (type & CR_TYPE_W) _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
