In certain situations (when the guest has to be paused, suspended, migrated, etc.), the device manager will use this new ioctl in order to trigger the KVMI_VM_EVENT_UNHOOK event. If the event is sent successfully (the VM has an active introspection channel), the device manager should delay the action (pause/suspend/...) to give the introspection tool the chance to remove its hooks (eg. breakpoints) while the guest is still running. Once a timeout is reached or the introspection tool has closed the socket, the device manager should resume the action.
Signed-off-by: Adalbert Lazăr <ala...@bitdefender.com> --- Documentation/virt/kvm/api.rst | 28 ++++++++++++++++++++++++++++ Documentation/virt/kvm/kvmi.rst | 7 ++++--- include/linux/kvmi_host.h | 1 + include/uapi/linux/kvm.h | 2 ++ virt/kvm/introspection/kvmi.c | 30 ++++++++++++++++++++++++++++++ virt/kvm/introspection/kvmi_int.h | 1 + virt/kvm/introspection/kvmi_msg.c | 5 +++++ virt/kvm/kvm_main.c | 5 +++++ 8 files changed, 76 insertions(+), 3 deletions(-) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index f3698413ddab..e6544d94e040 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -4946,6 +4946,34 @@ the event is disallowed. Unless set to -1 (meaning all events), id must be a event ID (e.g. KVMI_VM_EVENT_UNHOOK, KVMI_VCPU_EVENT_CR, etc.) +4.131 KVM_INTROSPECTION_PREUNHOOK +--------------------------------- + +:Capability: KVM_CAP_INTROSPECTION +:Architectures: x86 +:Type: vm ioctl +:Parameters: none +:Returns: 0 on success, a negative value on error + +Errors: + + ====== ============================================================ + EFAULT the VM is not introspected yet (use KVM_INTROSPECTION_HOOK) + ENOENT the socket (passed with KVM_INTROSPECTION_HOOK) had an error + ENOENT the introspection tool didn't subscribed + to this type of introspection event (unhook) + ====== ============================================================ + +This ioctl is used to inform that the current VM is +paused/suspended/migrated/etc. + +KVM should send an 'unhook' introspection event to the introspection tool. + +If this ioctl is successful, the userspace should give the +introspection tool a chance to unhook the VM and then it should use +KVM_INTROSPECTION_UNHOOK to make sure all the introspection structures +are freed. + 5. The kvm_run structure ======================== diff --git a/Documentation/virt/kvm/kvmi.rst b/Documentation/virt/kvm/kvmi.rst index 6f8583d4aeb2..33490bc9d1c1 100644 --- a/Documentation/virt/kvm/kvmi.rst +++ b/Documentation/virt/kvm/kvmi.rst @@ -183,9 +183,10 @@ becomes necessary to remove them before the guest is suspended, moved (migrated) or a snapshot with memory is created. The actions are normally performed by the device manager. In the case -of QEMU, it will use another ioctl to notify the introspection tool and -wait for a limited amount of time (a few seconds) for a confirmation that -is OK to proceed (the introspection tool will close the connection). +of QEMU, it will use the *KVM_INTROSPECTION_PREUNHOOK* ioctl to trigger +the *KVMI_VM_EVENT_UNHOOK* event and wait for a limited amount of time (a +few seconds) for a confirmation that is OK to proceed. The introspection +tool will close the connection to signal this. Live migrations --------------- diff --git a/include/linux/kvmi_host.h b/include/linux/kvmi_host.h index a5ede07686b9..81eac9f53a3f 100644 --- a/include/linux/kvmi_host.h +++ b/include/linux/kvmi_host.h @@ -32,6 +32,7 @@ int kvmi_ioctl_command(struct kvm *kvm, const struct kvm_introspection_feature *feat); int kvmi_ioctl_event(struct kvm *kvm, const struct kvm_introspection_feature *feat); +int kvmi_ioctl_preunhook(struct kvm *kvm); #else diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index c69140893f68..a29fbdf93b84 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1661,6 +1661,8 @@ struct kvm_introspection_feature { #define KVM_INTROSPECTION_COMMAND _IOW(KVMIO, 0xca, struct kvm_introspection_feature) #define KVM_INTROSPECTION_EVENT _IOW(KVMIO, 0xcb, struct kvm_introspection_feature) +#define KVM_INTROSPECTION_PREUNHOOK _IO(KVMIO, 0xcc) + #define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0) #define KVM_DEV_ASSIGN_PCI_2_3 (1 << 1) #define KVM_DEV_ASSIGN_MASK_INTX (1 << 2) diff --git a/virt/kvm/introspection/kvmi.c b/virt/kvm/introspection/kvmi.c index d103061b5da6..fa2fa41f00a1 100644 --- a/virt/kvm/introspection/kvmi.c +++ b/virt/kvm/introspection/kvmi.c @@ -384,3 +384,33 @@ int kvmi_ioctl_command(struct kvm *kvm, mutex_unlock(&kvm->kvmi_lock); return err; } + +static bool kvmi_unhook_event(struct kvm_introspection *kvmi) +{ + int err; + + err = kvmi_msg_send_unhook(kvmi); + + return !err; +} + +int kvmi_ioctl_preunhook(struct kvm *kvm) +{ + struct kvm_introspection *kvmi; + int err = 0; + + mutex_lock(&kvm->kvmi_lock); + + kvmi = KVMI(kvm); + if (!kvmi) { + err = -EFAULT; + goto out; + } + + if (!kvmi_unhook_event(kvmi)) + err = -ENOENT; + +out: + mutex_unlock(&kvm->kvmi_lock); + return err; +} diff --git a/virt/kvm/introspection/kvmi_int.h b/virt/kvm/introspection/kvmi_int.h index 1e1d1fad4035..ef4850e8bfae 100644 --- a/virt/kvm/introspection/kvmi_int.h +++ b/virt/kvm/introspection/kvmi_int.h @@ -18,6 +18,7 @@ bool kvmi_sock_get(struct kvm_introspection *kvmi, int fd); void kvmi_sock_shutdown(struct kvm_introspection *kvmi); void kvmi_sock_put(struct kvm_introspection *kvmi); bool kvmi_msg_process(struct kvm_introspection *kvmi); +int kvmi_msg_send_unhook(struct kvm_introspection *kvmi); /* kvmi.c */ void *kvmi_msg_alloc(void); diff --git a/virt/kvm/introspection/kvmi_msg.c b/virt/kvm/introspection/kvmi_msg.c index f0f5058403dd..513681290305 100644 --- a/virt/kvm/introspection/kvmi_msg.c +++ b/virt/kvm/introspection/kvmi_msg.c @@ -260,3 +260,8 @@ bool kvmi_msg_process(struct kvm_introspection *kvmi) out: return err == 0; } + +int kvmi_msg_send_unhook(struct kvm_introspection *kvmi) +{ + return -1; +} diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 8256e9acd7b2..0af64c12a2a9 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -4056,6 +4056,11 @@ static long kvm_vm_ioctl(struct file *filp, r = kvmi_ioctl_command(kvm, &feat); break; } + case KVM_INTROSPECTION_PREUNHOOK: + r = -EPERM; + if (enable_introspection) + r = kvmi_ioctl_preunhook(kvm); + break; #endif /* CONFIG_KVM_INTROSPECTION */ default: r = kvm_arch_vm_ioctl(filp, ioctl, arg); _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization