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[91.199.104.161]) by mx.google.com with ESMTPS id v17si8013050wro.188.2019.08.09.09.00.55 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 09 Aug 2019 09:00:55 -0700 (PDT) Received-SPF: pass (google.com: domain of alazar@bitdefender.com designates 91.199.104.161 as permitted sender) client-ip=91.199.104.161; Authentication-Results: mx.google.com; spf=pass (google.com: domain of alazar@bitdefender.com designates 91.199.104.161 as permitted sender) smtp.mailfrom=alazar@bitdefender.com Received: from smtp.bitdefender.com (smtp02.buh.bitdefender.net [10.17.80.76]) by mx01.bbu.dsd.mx.bitdefender.com (Postfix) with ESMTPS id A06B1301AB49; Fri, 9 Aug 2019 19:00:54 +0300 (EEST) Received: from localhost.localdomain (unknown [89.136.169.210]) by smtp.bitdefender.com (Postfix) with ESMTPSA id 5C80F305B7A3; Fri, 9 Aug 2019 19:00:54 +0300 (EEST) From: =?UTF-8?q?Adalbert=20Laz=C4=83r?= To: kvm@vger.kernel.org Cc: linux-mm@kvack.org, virtualization@lists.linux-foundation.org, Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Konrad Rzeszutek Wilk , Tamas K Lengyel , Mathieu Tarral , =?UTF-8?q?Samuel=20Laur=C3=A9n?= , Patrick Colp , Jan Kiszka , Stefan Hajnoczi , Weijiang Yang , Zhang@kvack.org, Yu C , =?UTF-8?q?Mihai=20Don=C8=9Bu?= , =?UTF-8?q?Adalbert=20Laz=C4=83r?= Subject: [RFC PATCH v6 08/92] kvm: introspection: add KVMI_CHECK_COMMAND and KVMI_CHECK_EVENT Date: Fri, 9 Aug 2019 18:59:23 +0300 Message-Id: <20190809160047.8319-9-alazar@bitdefender.com> In-Reply-To: <20190809160047.8319-1-alazar@bitdefender.com> References: <20190809160047.8319-1-alazar@bitdefender.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Archived-At: List-Archive: List-Post: These commands can be used by the introspection tool to check what introspection commands and events are supported (by KVMi) and allowed (by userspace/QEMU). The introspection tool will get one of the following error codes: * -KVM_EOPNOTSUPP (unsupported command/event) * -KVM_PERM (disallowed command/event) * -KVM_EINVAL (the padding space, used for future extensions, is not zero) * 0 (the command/event is supported and allowed) These commands can be seen as an alternative method to KVMI_GET_VERSION in checking if the introspection supports a specific command/event. As with the KVMI_GET_VERSION command, these commands can never be disallowed by userspace/QEMU. Signed-off-by: Adalbert Lazăr --- Documentation/virtual/kvm/kvmi.rst | 60 ++++++++++++++++++++++++++++++ include/uapi/linux/kvmi.h | 12 ++++++ virt/kvm/kvmi.c | 8 +++- virt/kvm/kvmi_msg.c | 38 +++++++++++++++++++ 4 files changed, 117 insertions(+), 1 deletion(-) diff --git a/Documentation/virtual/kvm/kvmi.rst b/Documentation/virtual/kvm/kvmi.rst index 82de474d512b..61cf69aa5d07 100644 --- a/Documentation/virtual/kvm/kvmi.rst +++ b/Documentation/virtual/kvm/kvmi.rst @@ -302,3 +302,63 @@ While the command reply is disabled: * the reply status is ignored for any unsupported/unknown or disallowed commands (and ``struct kvmi_error_code`` will be sent with -KVM_EOPNOTSUPP or -KVM_PERM). + +3. KVMI_CHECK_COMMAND +--------------------- + +:Architectures: all +:Versions: >= 1 +:Parameters: + +:: + + struct kvmi_check_command { + __u16 id; + __u16 padding1; + __u32 padding2; + }; + +:Returns: + +:: + + struct kvmi_error_code; + +Checks if the command specified by ``id`` is allowed. + +This command is always allowed. + +:Errors: + +* -KVM_PERM - the command specified by ``id`` is disallowed +* -KVM_EINVAL - padding is not zero + +4. KVMI_CHECK_EVENT +------------------- + +:Architectures: all +:Versions: >= 1 +:Parameters: + +:: + + struct kvmi_check_event { + __u16 id; + __u16 padding1; + __u32 padding2; + }; + +:Returns: + +:: + + struct kvmi_error_code; + +Checks if the event specified by ``id`` is allowed. + +This command is always allowed. + +:Errors: + +* -KVM_PERM - the event specified by ``id`` is disallowed +* -KVM_EINVAL - padding is not zero diff --git a/include/uapi/linux/kvmi.h b/include/uapi/linux/kvmi.h index a1ab39c5b8e0..7390303371c9 100644 --- a/include/uapi/linux/kvmi.h +++ b/include/uapi/linux/kvmi.h @@ -90,4 +90,16 @@ struct kvmi_control_cmd_response { __u32 padding2; }; +struct kvmi_check_command { + __u16 id; + __u16 padding1; + __u32 padding2; +}; + +struct kvmi_check_event { + __u16 id; + __u16 padding1; + __u32 padding2; +}; + #endif /* _UAPI__LINUX_KVMI_H */ diff --git a/virt/kvm/kvmi.c b/virt/kvm/kvmi.c index d5b6af21564e..dc1bb8326763 100644 --- a/virt/kvm/kvmi.c +++ b/virt/kvm/kvmi.c @@ -69,6 +69,8 @@ static bool alloc_kvmi(struct kvm *kvm, const struct kvm_introspection *qemu) return false; set_bit(KVMI_GET_VERSION, ikvm->cmd_allow_mask); + set_bit(KVMI_CHECK_COMMAND, ikvm->cmd_allow_mask); + set_bit(KVMI_CHECK_EVENT, ikvm->cmd_allow_mask); memcpy(&ikvm->uuid, &qemu->uuid, sizeof(ikvm->uuid)); @@ -295,10 +297,14 @@ int kvmi_ioctl_command(struct kvm *kvm, void __user *argp) if (!allow) { DECLARE_BITMAP(always_allowed, KVMI_NUM_COMMANDS); - if (id == KVMI_GET_VERSION) + if (id == KVMI_GET_VERSION + || id == KVMI_CHECK_COMMAND + || id == KVMI_CHECK_EVENT) return -EPERM; set_bit(KVMI_GET_VERSION, always_allowed); + set_bit(KVMI_CHECK_COMMAND, always_allowed); + set_bit(KVMI_CHECK_EVENT, always_allowed); bitmap_andnot(requested, requested, always_allowed, KVMI_NUM_COMMANDS); diff --git a/virt/kvm/kvmi_msg.c b/virt/kvm/kvmi_msg.c index 2237a6ed25f6..e24996611e3a 100644 --- a/virt/kvm/kvmi_msg.c +++ b/virt/kvm/kvmi_msg.c @@ -9,6 +9,8 @@ #include "kvmi_int.h" static const char *const msg_IDs[] = { + [KVMI_CHECK_COMMAND] = "KVMI_CHECK_COMMAND", + [KVMI_CHECK_EVENT] = "KVMI_CHECK_EVENT", [KVMI_CONTROL_CMD_RESPONSE] = "KVMI_CONTROL_CMD_RESPONSE", [KVMI_GET_VERSION] = "KVMI_GET_VERSION", }; @@ -177,6 +179,40 @@ static bool is_command_allowed(struct kvmi *ikvm, int id) return test_bit(id, ikvm->cmd_allow_mask); } +static int handle_check_command(struct kvmi *ikvm, + const struct kvmi_msg_hdr *msg, + const void *_req) +{ + const struct kvmi_check_command *req = _req; + int ec = 0; + + if (req->padding1 || req->padding2) + ec = -KVM_EINVAL; + else if (!is_command_allowed(ikvm, req->id)) + ec = -KVM_EPERM; + + return kvmi_msg_vm_maybe_reply(ikvm, msg, ec, NULL, 0); +} + +static bool is_event_allowed(struct kvmi *ikvm, int id) +{ + return test_bit(id, ikvm->event_allow_mask); +} + +static int handle_check_event(struct kvmi *ikvm, + const struct kvmi_msg_hdr *msg, const void *_req) +{ + const struct kvmi_check_event *req = _req; + int ec = 0; + + if (req->padding1 || req->padding2) + ec = -KVM_EINVAL; + else if (!is_event_allowed(ikvm, req->id)) + ec = -KVM_EPERM; + + return kvmi_msg_vm_maybe_reply(ikvm, msg, ec, NULL, 0); +} + static int handle_control_cmd_response(struct kvmi *ikvm, const struct kvmi_msg_hdr *msg, const void *_req) @@ -207,6 +243,8 @@ static int handle_control_cmd_response(struct kvmi *ikvm, */ static int(*const msg_vm[])(struct kvmi *, const struct kvmi_msg_hdr *, const void *) = { + [KVMI_CHECK_COMMAND] = handle_check_command, + [KVMI_CHECK_EVENT] = handle_check_event, [KVMI_CONTROL_CMD_RESPONSE] = handle_control_cmd_response, [KVMI_GET_VERSION] = handle_get_version, };