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[91.199.104.161]) by mx.google.com with ESMTPS id w4si85104276wrn.31.2019.08.09.09.00.54 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 09 Aug 2019 09:00:54 -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 0D891301AB48; 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 BFC3E305B7A4; Fri, 9 Aug 2019 19:00:53 +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 06/92] kvm: introspection: add KVMI_CONTROL_CMD_RESPONSE Date: Fri, 9 Aug 2019 18:59:21 +0300 Message-Id: <20190809160047.8319-7-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: This command enables/disables the command replies. It is useful when the introspection tool send multiple messages with one write() call and doesn't have to wait for a reply. IIRC, the speed improvment seen during UnixBench tests in a VM introspected through vsock (the introspection tool was running in a different VM) was around 5-10%. Signed-off-by: Adalbert Lazăr --- Documentation/virtual/kvm/kvmi.rst | 50 ++++++++++++++++++++++++++ include/uapi/linux/kvmi.h | 7 ++++ virt/kvm/kvmi_int.h | 2 ++ virt/kvm/kvmi_msg.c | 57 ++++++++++++++++++++++++++++++ 4 files changed, 116 insertions(+) diff --git a/Documentation/virtual/kvm/kvmi.rst b/Documentation/virtual/kvm/kvmi.rst index 0f296e3c4244..82de474d512b 100644 --- a/Documentation/virtual/kvm/kvmi.rst +++ b/Documentation/virtual/kvm/kvmi.rst @@ -252,3 +252,53 @@ Returns the introspection API version. This command is always allowed and successful (if the introspection is built in kernel). + +2. KVMI_CONTROL_CMD_RESPONSE +---------------------------- + +:Architectures: all +:Versions: >= 1 +:Parameters: + +:: + + struct kvmi_control_cmd_response { + __u8 enable; + __u8 now; + __u16 padding1; + __u32 padding2; + }; + +:Returns: + +:: + struct kvmi_error_code + +Enables or disables the command replies. By default, all commands need +a reply. + +If `now` is 1, the command reply is enabled/disabled (according to +`enable`) starting with the current command. For example, `enable=0` +and `now=1` means that the reply is disabled for this command too, +while `enable=0` and `now=0` means that a reply will be send for this +command, but not for the next ones (until enabled back with another +*KVMI_CONTROL_CMD_RESPONSE*). + +This command is used by the introspection tool to disable the replies +for commands returning an error code only (eg. *KVMI_SET_REGISTERS*) +when an error is less likely to happen. For example, the following +commands can be used to reply to an event with a single `write()` call: + + KVMI_CONTROL_CMD_RESPONSE enable=0 now=1 + KVMI_SET_REGISTERS vcpu=N + KVMI_EVENT_REPLY vcpu=N + KVMI_CONTROL_CMD_RESPONSE enable=1 now=0 + +While the command reply is disabled: + +* the socket will be closed on any command for which the reply should + contain more than just an error code (eg. *KVMI_GET_REGISTERS*) + +* 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). diff --git a/include/uapi/linux/kvmi.h b/include/uapi/linux/kvmi.h index 9574ba0b9565..a1ab39c5b8e0 100644 --- a/include/uapi/linux/kvmi.h +++ b/include/uapi/linux/kvmi.h @@ -83,4 +83,11 @@ struct kvmi_get_version_reply { __u32 padding; }; +struct kvmi_control_cmd_response { + __u8 enable; + __u8 now; + __u16 padding1; + __u32 padding2; +}; + #endif /* _UAPI__LINUX_KVMI_H */ diff --git a/virt/kvm/kvmi_int.h b/virt/kvm/kvmi_int.h index 76119a4b69d8..157f765fb34d 100644 --- a/virt/kvm/kvmi_int.h +++ b/virt/kvm/kvmi_int.h @@ -85,6 +85,8 @@ struct kvmi { DECLARE_BITMAP(cmd_allow_mask, KVMI_NUM_COMMANDS); DECLARE_BITMAP(event_allow_mask, KVMI_NUM_EVENTS); + + bool cmd_reply_disabled; }; /* kvmi_msg.c */ diff --git a/virt/kvm/kvmi_msg.c b/virt/kvm/kvmi_msg.c index 6fe04de29f7e..ea5c7e23669a 100644 --- a/virt/kvm/kvmi_msg.c +++ b/virt/kvm/kvmi_msg.c @@ -9,6 +9,7 @@ #include "kvmi_int.h" static const char *const msg_IDs[] = { + [KVMI_CONTROL_CMD_RESPONSE] = "KVMI_CONTROL_CMD_RESPONSE", [KVMI_GET_VERSION] = "KVMI_GET_VERSION", }; @@ -130,6 +131,36 @@ static int kvmi_msg_vm_reply(struct kvmi *ikvm, return kvmi_msg_reply(ikvm, msg, err, rpl, rpl_size); } +static bool kvmi_validate_no_reply(struct kvmi *ikvm, + const struct kvmi_msg_hdr *msg, + size_t rpl_size, int err) +{ + if (rpl_size) { + kvmi_err(ikvm, "Reply disabled for command %d", msg->id); + return false; + } + + if (err) + kvmi_warn(ikvm, "Error code %d discarded for message id %d\n", + err, msg->id); + + return true; +} + +static int kvmi_msg_vm_maybe_reply(struct kvmi *ikvm, + const struct kvmi_msg_hdr *msg, + int err, const void *rpl, + size_t rpl_size) +{ + if (ikvm->cmd_reply_disabled) { + if (!kvmi_validate_no_reply(ikvm, msg, rpl_size, err)) + return -KVM_EINVAL; + return 0; + } + + return kvmi_msg_vm_reply(ikvm, msg, err, rpl, rpl_size); +} + static int handle_get_version(struct kvmi *ikvm, const struct kvmi_msg_hdr *msg, const void *req) { @@ -146,11 +177,37 @@ static bool is_command_allowed(struct kvmi *ikvm, int id) return test_bit(id, ikvm->cmd_allow_mask); } +static int handle_control_cmd_response(struct kvmi *ikvm, + const struct kvmi_msg_hdr *msg, + const void *_req) +{ + const struct kvmi_control_cmd_response *req = _req; + bool disabled, now; + int err; + + if (req->padding1 || req->padding2) + return -KVM_EINVAL; + + disabled = !req->enable; + now = (req->now == 1); + + if (now) + ikvm->cmd_reply_disabled = disabled; + + err = kvmi_msg_vm_maybe_reply(ikvm, msg, 0, NULL, 0); + + if (!now) + ikvm->cmd_reply_disabled = disabled; + + return err; +} + /* * These commands are executed on the receiving thread/worker. */ static int(*const msg_vm[])(struct kvmi *, const struct kvmi_msg_hdr *, const void *) = { + [KVMI_CONTROL_CMD_RESPONSE] = handle_control_cmd_response, [KVMI_GET_VERSION] = handle_get_version, };