From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 39BD5C2D0E9 for ; Mon, 30 Mar 2020 10:20:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 05D5220733 for ; Mon, 30 Mar 2020 10:20:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729795AbgC3KUI (ORCPT ); Mon, 30 Mar 2020 06:20:08 -0400 Received: from mx01.bbu.dsd.mx.bitdefender.com ([91.199.104.161]:43852 "EHLO mx01.bbu.dsd.mx.bitdefender.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729681AbgC3KUH (ORCPT ); Mon, 30 Mar 2020 06:20:07 -0400 Received: from smtp.bitdefender.com (smtp02.buh.bitdefender.net [10.17.80.76]) by mx01.bbu.dsd.mx.bitdefender.com (Postfix) with ESMTPS id D9AE3307503A; Mon, 30 Mar 2020 13:12:54 +0300 (EEST) Received: from localhost.localdomain (unknown [91.199.104.28]) by smtp.bitdefender.com (Postfix) with ESMTPSA id B83CA305B7A1; Mon, 30 Mar 2020 13:12:54 +0300 (EEST) From: =?UTF-8?q?Adalbert=20Laz=C4=83r?= To: kvm@vger.kernel.org Cc: virtualization@lists.linux-foundation.org, Paolo Bonzini , =?UTF-8?q?Adalbert=20Laz=C4=83r?= , =?UTF-8?q?Mircea=20C=C3=AErjaliu?= , =?UTF-8?q?Nicu=C8=99or=20C=C3=AE=C8=9Bu?= Subject: [PATCH v8 39/81] KVM: introspection: add hook/unhook ioctls Date: Mon, 30 Mar 2020 13:12:26 +0300 Message-Id: <20200330101308.21702-40-alazar@bitdefender.com> In-Reply-To: <20200330101308.21702-1-alazar@bitdefender.com> References: <20200330101308.21702-1-alazar@bitdefender.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On hook, a new thread is created to handle the messages coming from the introspection tool (commands or event replies). Co-developed-by: Mircea Cîrjaliu Signed-off-by: Mircea Cîrjaliu Co-developed-by: Nicușor Cîțu Signed-off-by: Nicușor Cîțu Signed-off-by: Adalbert Lazăr --- Documentation/virt/kvm/api.rst | 50 ++++++ arch/x86/include/asm/kvmi_host.h | 8 + arch/x86/kvm/Makefile | 2 +- arch/x86/kvm/x86.c | 5 + include/linux/kvm_host.h | 4 + include/linux/kvmi_host.h | 17 ++ include/uapi/linux/kvm.h | 10 ++ include/uapi/linux/kvmi.h | 13 ++ tools/testing/selftests/kvm/Makefile | 1 + .../testing/selftests/kvm/x86_64/kvmi_test.c | 83 +++++++++ virt/kvm/introspection/kvmi.c | 161 ++++++++++++++++++ virt/kvm/introspection/kvmi_int.h | 20 +++ virt/kvm/introspection/kvmi_msg.c | 39 +++++ virt/kvm/kvm_main.c | 11 ++ 14 files changed, 423 insertions(+), 1 deletion(-) create mode 100644 arch/x86/include/asm/kvmi_host.h create mode 100644 include/uapi/linux/kvmi.h create mode 100644 tools/testing/selftests/kvm/x86_64/kvmi_test.c create mode 100644 virt/kvm/introspection/kvmi_msg.c diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index ebd383fba939..3ff42e5e6d63 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -4648,6 +4648,56 @@ This ioctl resets VCPU registers and control structures according to the clear cpu reset definition in the POP. However, the cpu is not put into ESA mode. This reset is a superset of the initial reset. +4.125 KVM_INTROSPECTION_HOOK +---------------------------- + +:Capability: KVM_CAP_INTROSPECTION +:Architectures: x86 +:Type: vm ioctl +:Parameters: struct kvm_introspection (in) +:Returns: 0 on success, a negative value on error + +Errors: + + ====== ========================================================== + EFAULT the introspection is not enabled + ENOMEM the memory allocation failed + EEXIST the VM is already introspected + EINVAL the file descriptor doesn't correspond to an active socket + EINVAL the padding is not zero + EPERM the introspection is disabled (kvm.introspection=0) + ====== ========================================================== + +This ioctl is used to enable the introspection of the current VM. + +:: + + struct kvm_introspection { + __s32 fd; + __u32 padding; + __u8 uuid[16]; + }; + +fd is the file descriptor of a socket connected to the introspection tool, + +padding must be zero (it might be used in the future), + +uuid is used for debug and error messages. + +The KVMI version can be retrieved using the KVM_CAP_INTROSPECTION of +the KVM_CHECK_EXTENSION ioctl() at run-time. + +4.126 KVM_INTROSPECTION_UNHOOK +------------------------------ + +:Capability: KVM_CAP_INTROSPECTION +:Architectures: x86 +:Type: vm ioctl +:Parameters: none +:Returns: 0 on success, a negative value on error + +This ioctl is used to free all introspection structures +related to this VM. 5. The kvm_run structure ======================== diff --git a/arch/x86/include/asm/kvmi_host.h b/arch/x86/include/asm/kvmi_host.h new file mode 100644 index 000000000000..38c398262913 --- /dev/null +++ b/arch/x86/include/asm/kvmi_host.h @@ -0,0 +1,8 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_X86_KVMI_HOST_H +#define _ASM_X86_KVMI_HOST_H + +struct kvm_arch_introspection { +}; + +#endif /* _ASM_X86_KVMI_HOST_H */ diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile index f443198f782c..9d05b5bf2360 100644 --- a/arch/x86/kvm/Makefile +++ b/arch/x86/kvm/Makefile @@ -9,7 +9,7 @@ KVMI := $(KVM)/introspection kvm-y += $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o \ $(KVM)/eventfd.o $(KVM)/irqchip.o $(KVM)/vfio.o kvm-$(CONFIG_KVM_ASYNC_PF) += $(KVM)/async_pf.o -kvm-$(CONFIG_KVM_INTROSPECTION) += $(KVMI)/kvmi.o +kvm-$(CONFIG_KVM_INTROSPECTION) += $(KVMI)/kvmi.o $(KVMI)/kvmi_msg.o kvm-y += x86.o emulate.o i8259.o irq.o lapic.o \ i8254.o ioapic.o irq_comm.o cpuid.o pmu.o mtrr.o \ diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 2aaa0dd8b02a..4fa11c998325 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3403,6 +3403,11 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_HYPERV_ENLIGHTENED_VMCS: r = kvm_x86_ops->nested_enable_evmcs != NULL; break; +#ifdef CONFIG_KVM_INTROSPECTION + case KVM_CAP_INTROSPECTION: + r = KVMI_VERSION; + break; +#endif default: break; } diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 5d1a73b5d94f..1f1b0dffabaa 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -501,6 +501,10 @@ struct kvm { struct srcu_struct srcu; struct srcu_struct irq_srcu; pid_t userspace_pid; + struct mutex kvmi_lock; + refcount_t kvmi_ref; + struct completion kvmi_complete; + struct kvm_introspection *kvmi; }; #define kvm_err(fmt, ...) \ diff --git a/include/linux/kvmi_host.h b/include/linux/kvmi_host.h index 8cd613fdd4f2..c8b9c87ecff2 100644 --- a/include/linux/kvmi_host.h +++ b/include/linux/kvmi_host.h @@ -2,8 +2,22 @@ #ifndef __KVMI_HOST_H #define __KVMI_HOST_H +#include + struct kvm; +#include + +struct kvm_introspection { + struct kvm_arch_introspection arch; + struct kvm *kvm; + + uuid_t uuid; + + struct socket *sock; + struct task_struct *recv; +}; + #ifdef CONFIG_KVM_INTROSPECTION int kvmi_init(void); @@ -11,6 +25,9 @@ void kvmi_uninit(void); void kvmi_create_vm(struct kvm *kvm); void kvmi_destroy_vm(struct kvm *kvm); +int kvmi_ioctl_hook(struct kvm *kvm, void __user *argp); +int kvmi_ioctl_unhook(struct kvm *kvm); + #else static inline int kvmi_init(void) { return 0; } diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 4b95f9a31a2f..6d1076ed93a7 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1010,6 +1010,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_ARM_NISV_TO_USER 177 #define KVM_CAP_ARM_INJECT_EXT_DABT 178 #define KVM_CAP_S390_VCPU_RESETS 179 +#define KVM_CAP_INTROSPECTION 180 #ifdef KVM_CAP_IRQ_ROUTING @@ -1558,6 +1559,15 @@ struct kvm_sev_dbg { __u32 len; }; +struct kvm_introspection_hook { + __s32 fd; + __u32 padding; + __u8 uuid[16]; +}; + +#define KVM_INTROSPECTION_HOOK _IOW(KVMIO, 0xc3, struct kvm_introspection_hook) +#define KVM_INTROSPECTION_UNHOOK _IO(KVMIO, 0xc4) + #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/include/uapi/linux/kvmi.h b/include/uapi/linux/kvmi.h new file mode 100644 index 000000000000..34dda91016db --- /dev/null +++ b/include/uapi/linux/kvmi.h @@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef _UAPI__LINUX_KVMI_H +#define _UAPI__LINUX_KVMI_H + +/* + * KVMI structures and definitions + */ + +enum { + KVMI_VERSION = 0x00000001 +}; + +#endif /* _UAPI__LINUX_KVMI_H */ diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index d91c53b726e6..ed334fd48ce4 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -15,6 +15,7 @@ LIBKVM_s390x = lib/s390x/processor.c lib/s390x/ucall.c TEST_GEN_PROGS_x86_64 = x86_64/cr4_cpuid_sync_test TEST_GEN_PROGS_x86_64 += x86_64/evmcs_test TEST_GEN_PROGS_x86_64 += x86_64/hyperv_cpuid +TEST_GEN_PROGS_x86_64 += x86_64/kvmi_test TEST_GEN_PROGS_x86_64 += x86_64/mmio_warning_test TEST_GEN_PROGS_x86_64 += x86_64/platform_info_test TEST_GEN_PROGS_x86_64 += x86_64/set_sregs_test diff --git a/tools/testing/selftests/kvm/x86_64/kvmi_test.c b/tools/testing/selftests/kvm/x86_64/kvmi_test.c new file mode 100644 index 000000000000..100f05c518aa --- /dev/null +++ b/tools/testing/selftests/kvm/x86_64/kvmi_test.c @@ -0,0 +1,83 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KVM introspection tests + * + * Copyright (C) 2020, Bitdefender S.R.L. + */ + +#define _GNU_SOURCE /* for program_invocation_short_name */ +#include +#include + +#include "test_util.h" + +#include "kvm_util.h" +#include "processor.h" +#include "../lib/kvm_util_internal.h" + +#include "linux/kvmi.h" + +#define VCPU_ID 5 + +static int socket_pair[2]; +#define Kvm_socket socket_pair[0] +#define Userspace_socket socket_pair[1] + +void setup_socket(void) +{ + int r; + + r = socketpair(AF_UNIX, SOCK_STREAM, 0, socket_pair); + TEST_ASSERT(r == 0, + "socketpair() failed, errno %d (%s)\n", + errno, strerror(errno)); +} + +static void hook_introspection(struct kvm_vm *vm) +{ + struct kvm_introspection_hook hook = {.fd = Kvm_socket}; + int r; + + r = ioctl(vm->fd, KVM_INTROSPECTION_HOOK, &hook); + TEST_ASSERT(r == 0, + "KVM_INTROSPECTION_HOOK failed, errno %d (%s)\n", + errno, strerror(errno)); +} + +static void unhook_introspection(struct kvm_vm *vm) +{ + int r; + + r = ioctl(vm->fd, KVM_INTROSPECTION_UNHOOK, NULL); + TEST_ASSERT(r == 0, + "KVM_INTROSPECTION_UNHOOK failed, errno %d (%s)\n", + errno, strerror(errno)); +} + +static void test_introspection(struct kvm_vm *vm) +{ + setup_socket(); + hook_introspection(vm); + unhook_introspection(vm); +} + +int main(int argc, char *argv[]) +{ + struct kvm_vm *vm; + int version; + + version = kvm_check_cap(KVM_CAP_INTROSPECTION); + if (version != KVMI_VERSION) { + fprintf(stderr, + "KVM_CAP_INTROSPECTION not available, skipping tests\n"); + exit(KSFT_SKIP); + } + + vm = vm_create_default(VCPU_ID, 0, NULL); + vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid()); + + test_introspection(vm); + + kvm_vm_free(vm); + return 0; +} diff --git a/virt/kvm/introspection/kvmi.c b/virt/kvm/introspection/kvmi.c index c74ddb8075cd..ecebb00b4245 100644 --- a/virt/kvm/introspection/kvmi.c +++ b/virt/kvm/introspection/kvmi.c @@ -6,6 +6,7 @@ * */ #include "kvmi_int.h" +#include int kvmi_init(void) { @@ -16,10 +17,170 @@ void kvmi_uninit(void) { } +static void free_kvmi(struct kvm *kvm) +{ + kfree(kvm->kvmi); + kvm->kvmi = NULL; +} + +static struct kvm_introspection * +alloc_kvmi(struct kvm *kvm, const struct kvm_introspection_hook *hook) +{ + struct kvm_introspection *kvmi; + + kvmi = kzalloc(sizeof(*kvmi), GFP_KERNEL); + if (!kvmi) + return NULL; + + BUILD_BUG_ON(sizeof(hook->uuid) != sizeof(kvmi->uuid)); + memcpy(&kvmi->uuid, &hook->uuid, sizeof(kvmi->uuid)); + + kvmi->kvm = kvm; + + return kvmi; +} + +static void kvmi_destroy(struct kvm_introspection *kvmi) +{ + struct kvm *kvm = kvmi->kvm; + + free_kvmi(kvm); +} + +static void kvmi_stop_recv_thread(struct kvm_introspection *kvmi) +{ + kvmi_sock_shutdown(kvmi); +} + +static void __kvmi_unhook(struct kvm *kvm) +{ + struct kvm_introspection *kvmi = KVMI(kvm); + + wait_for_completion_killable(&kvm->kvmi_complete); + kvmi_sock_put(kvmi); +} + +static void kvmi_unhook(struct kvm *kvm) +{ + struct kvm_introspection *kvmi; + + mutex_lock(&kvm->kvmi_lock); + + kvmi = KVMI(kvm); + if (kvmi) { + kvmi_stop_recv_thread(kvmi); + __kvmi_unhook(kvm); + kvmi_destroy(kvmi); + } + + mutex_unlock(&kvm->kvmi_lock); +} + +int kvmi_ioctl_unhook(struct kvm *kvm) +{ + kvmi_unhook(kvm); + return 0; +} + +void kvmi_put(struct kvm *kvm) +{ + if (refcount_dec_and_test(&kvm->kvmi_ref)) + complete(&kvm->kvmi_complete); +} + +static int __kvmi_hook(struct kvm *kvm, + const struct kvm_introspection_hook *hook) +{ + struct kvm_introspection *kvmi = KVMI(kvm); + + if (!kvmi_sock_get(kvmi, hook->fd)) + return -EINVAL; + + return 0; +} + +static int kvmi_recv_thread(void *arg) +{ + struct kvm_introspection *kvmi = arg; + + while (kvmi_msg_process(kvmi)) + ; + + /* + * Signal userspace (which might wait for POLLHUP only) + * and prevent the vCPUs from sending other events. + */ + kvmi_sock_shutdown(kvmi); + + kvmi_put(kvmi->kvm); + return 0; +} + +int kvmi_hook(struct kvm *kvm, const struct kvm_introspection_hook *hook) +{ + struct kvm_introspection *kvmi; + int err = 0; + + mutex_lock(&kvm->kvmi_lock); + + if (kvm->kvmi) { + err = -EEXIST; + goto out; + } + + kvmi = alloc_kvmi(kvm, hook); + if (!kvmi) { + err = -ENOMEM; + goto out; + } + + kvm->kvmi = kvmi; + + err = __kvmi_hook(kvm, hook); + if (err) + goto destroy; + + init_completion(&kvm->kvmi_complete); + + refcount_set(&kvm->kvmi_ref, 1); + + kvmi->recv = kthread_run(kvmi_recv_thread, kvmi, "kvmi-recv"); + if (IS_ERR(kvmi->recv)) { + err = -ENOMEM; + kvmi_put(kvm); + goto unhook; + } + + goto out; + +unhook: + __kvmi_unhook(kvm); +destroy: + kvmi_destroy(kvmi); +out: + mutex_unlock(&kvm->kvmi_lock); + return err; +} + +int kvmi_ioctl_hook(struct kvm *kvm, void __user *argp) +{ + struct kvm_introspection_hook i; + + if (copy_from_user(&i, argp, sizeof(i))) + return -EFAULT; + + if (i.padding) + return -EINVAL; + + return kvmi_hook(kvm, &i); +} + void kvmi_create_vm(struct kvm *kvm) { + mutex_init(&kvm->kvmi_lock); } void kvmi_destroy_vm(struct kvm *kvm) { + kvmi_unhook(kvm); } diff --git a/virt/kvm/introspection/kvmi_int.h b/virt/kvm/introspection/kvmi_int.h index 34af926f9838..1c9cc15ab4d9 100644 --- a/virt/kvm/introspection/kvmi_int.h +++ b/virt/kvm/introspection/kvmi_int.h @@ -4,4 +4,24 @@ #include +#define kvmi_warn(kvmi, fmt, ...) \ + kvm_info("%pU WARNING: " fmt, &kvmi->uuid, ## __VA_ARGS__) +#define kvmi_warn_once(kvmi, fmt, ...) ({ \ + static bool __section(.data.once) __warned; \ + if (!__warned) { \ + __warned = true; \ + kvmi_warn(kvmi, fmt, ## __VA_ARGS__); \ + } \ + }) +#define kvmi_err(kvmi, fmt, ...) \ + kvm_info("%pU ERROR: " fmt, &kvmi->uuid, ## __VA_ARGS__) + +#define KVMI(kvm) ((kvm)->kvmi) + +/* kvmi_msg.c */ +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); + #endif diff --git a/virt/kvm/introspection/kvmi_msg.c b/virt/kvm/introspection/kvmi_msg.c new file mode 100644 index 000000000000..f9e66274fb43 --- /dev/null +++ b/virt/kvm/introspection/kvmi_msg.c @@ -0,0 +1,39 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KVM introspection (message handling) + * + * Copyright (C) 2017-2020 Bitdefender S.R.L. + * + */ +#include +#include "kvmi_int.h" + +bool kvmi_sock_get(struct kvm_introspection *kvmi, int fd) +{ + struct socket *sock; + int r; + + sock = sockfd_lookup(fd, &r); + if (!sock) + return false; + + kvmi->sock = sock; + + return true; +} + +void kvmi_sock_put(struct kvm_introspection *kvmi) +{ + if (kvmi->sock) + sockfd_put(kvmi->sock); +} + +void kvmi_sock_shutdown(struct kvm_introspection *kvmi) +{ + kernel_sock_shutdown(kvmi->sock, SHUT_RDWR); +} + +bool kvmi_msg_process(struct kvm_introspection *kvmi) +{ + return false; +} diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index b43923b5aa79..82634be560e6 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3580,6 +3580,17 @@ static long kvm_vm_ioctl(struct file *filp, case KVM_CHECK_EXTENSION: r = kvm_vm_ioctl_check_extension_generic(kvm, arg); break; +#ifdef CONFIG_KVM_INTROSPECTION + case KVM_INTROSPECTION_HOOK: + if (enable_introspection) + r = kvmi_ioctl_hook(kvm, argp); + else + r = -EPERM; + break; + case KVM_INTROSPECTION_UNHOOK: + r = kvmi_ioctl_unhook(kvm); + break; +#endif /* CONFIG_KVM_INTROSPECTION */ default: r = kvm_arch_vm_ioctl(filp, ioctl, arg); }