From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?q?Adalbert=20Laz=C4=83r?= Subject: [PATCH v9 65/84] KVM: introspection: restore the state of CR3 interception on unhook Date: Wed, 22 Jul 2020 00:09:03 +0300 Message-ID: <20200721210922.7646-66-alazar@bitdefender.com> References: <20200721210922.7646-1-alazar@bitdefender.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20200721210922.7646-1-alazar@bitdefender.com> Sender: kvm-owner@vger.kernel.org To: kvm@vger.kernel.org Cc: virtualization@lists.linux-foundation.org, Paolo Bonzini , =?UTF-8?q?Nicu=C8=99or=20C=C3=AE=C8=9Bu?= , =?UTF-8?q?Adalbert=20Laz=C4=83r?= List-Id: virtualization@lists.linuxfoundation.org From: Nicușor Cîțu 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 Signed-off-by: Adalbert Lazăr --- arch/x86/include/asm/kvmi_host.h | 4 ++ arch/x86/kvm/kvmi.c | 64 ++++++++++++++++++++++++++++++-- arch/x86/kvm/svm/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 1aff91ef8475..44580f77e34e 100644 --- a/arch/x86/include/asm/kvmi_host.h +++ b/arch/x86/include/asm/kvmi_host.h @@ -16,6 +16,7 @@ struct kvmi_interception { bool cleanup; bool restore_interception; struct kvmi_monitor_interception breakpoint; + struct kvmi_monitor_interception cr3w; }; struct kvm_vcpu_arch_introspection { @@ -31,6 +32,7 @@ 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 */ @@ -41,6 +43,8 @@ static inline bool kvmi_cr_event(struct kvm_vcpu *vcpu, unsigned int cr, 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 e72b2ef5b28a..e340a2c3500f 100644 --- a/arch/x86/kvm/kvmi.c +++ b/arch/x86/kvm/kvmi.c @@ -308,6 +308,59 @@ 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) { @@ -347,6 +400,7 @@ void kvmi_arch_breakpoint_event(struct kvm_vcpu *vcpu, u64 gva, u8 insn_len) static void kvmi_arch_restore_interception(struct kvm_vcpu *vcpu) { kvmi_arch_disable_bp_intercept(vcpu); + kvmi_arch_disable_cr3w_intercept(vcpu); } bool kvmi_arch_clean_up_interception(struct kvm_vcpu *vcpu) @@ -371,8 +425,13 @@ bool kvmi_arch_vcpu_alloc_interception(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); @@ -413,8 +472,7 @@ 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/svm.c b/arch/x86/kvm/svm/svm.c index 47c50e2f0f86..bc886cedf45c 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -1668,6 +1668,11 @@ 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 5d0876420dd9..69aa1157a0f0 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -3011,6 +3011,11 @@ 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)