vm-virtio: Add vhost-user-blk implementation

vhost-user-blk has better performance than virtio-blk, so we need
add vhost-user-blk support with SPDK in Rust-based VMMs.

Signed-off-by: Yang Zhong <yang.zhong@intel.com>

vm-virtio/src/lib.rs

@@ -130,6 +130,8 @@ pub enum ActivateError {
     VhostUserSetup(vhost_user::Error),
     /// Failed to setup vhost-user daemon.
     VhostUserNetSetup(vhost_user::Error),
+    /// Failed to setup vhost-user daemon.
+    VhostUserBlkSetup(vhost_user::Error),
 }
 
 pub type ActivateResult = std::result::Result<(), ActivateError>;

vm-virtio/src/vhost_user/blk.rs

@@ -0,0 +1,226 @@
+// Copyright 2019 Intel Corporation. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+use libc;
+use libc::EFD_NONBLOCK;
+use std::cmp;
+use std::io::Write;
+use std::ptr::null;
+use std::sync::{Arc, RwLock};
+use std::thread;
+use std::vec::Vec;
+
+use crate::VirtioInterrupt;
+
+use vm_memory::GuestMemoryMmap;
+use vmm_sys_util::eventfd::EventFd;
+
+use super::super::{ActivateError, ActivateResult, Queue, VirtioDevice, VirtioDeviceType};
+use super::handler::*;
+use super::vu_common_ctrl::*;
+use super::{Error, Result};
+use std::mem;
+use vhost_rs::vhost_user::message::VhostUserConfigFlags;
+use vhost_rs::vhost_user::message::{VhostUserProtocolFeatures, VhostUserVirtioFeatures};
+use vhost_rs::vhost_user::{Master, VhostUserMaster, VhostUserMasterReqHandler};
+use vhost_rs::VhostBackend;
+use virtio_bindings::bindings::virtio_blk::*;
+
+macro_rules! offset_of {
+    ($ty:ty, $field:ident) => {
+        unsafe { &(*(null() as *const $ty)).$field as *const _ as usize }
+    };
+}
+
+struct SlaveReqHandler {}
+impl VhostUserMasterReqHandler for SlaveReqHandler {}
+
+pub struct Blk {
+    vhost_user_blk: Master,
+    kill_evt: EventFd,
+    avail_features: u64,
+    acked_features: u64,
+    config_space: Vec<u8>,
+    queue_sizes: Vec<u16>,
+}
+
+impl<'a> Blk {
+    /// Create a new vhost-user-blk device
+    pub fn new(wce: bool, vu_cfg: VhostUserConfig<'a>) -> Result<Blk> {
+        let mut vhost_user_blk = Master::connect(vu_cfg.sock, vu_cfg.num_queues as u64)
+            .map_err(Error::VhostUserCreateMaster)?;
+
+        let kill_evt = EventFd::new(EFD_NONBLOCK).map_err(Error::CreateKillEventFd)?;
+
+        // Filling device and vring features VMM supports.
+        let mut avail_features = 1 << VIRTIO_BLK_F_SEG_MAX
+            | 1 << VIRTIO_BLK_F_RO
+            | 1 << VIRTIO_BLK_F_BLK_SIZE
+            | 1 << VIRTIO_BLK_F_FLUSH
+            | 1 << VIRTIO_BLK_F_TOPOLOGY
+            | 1 << VIRTIO_F_VERSION_1
+            | VhostUserVirtioFeatures::PROTOCOL_FEATURES.bits();
+
+        // Set vhost-user owner.
+        vhost_user_blk
+            .set_owner()
+            .map_err(Error::VhostUserSetOwner)?;
+
+        // Get features from backend, do negotiation to get a feature collection which
+        // both VMM and backend support.
+        let backend_features = vhost_user_blk
+            .get_features()
+            .map_err(Error::VhostUserGetFeatures)?;
+        avail_features &= backend_features;
+        // Set features back is required by the vhost crate mechanism, since the
+        // later vhost call will check if features is filled in master before execution.
+        vhost_user_blk
+            .set_features(avail_features)
+            .map_err(Error::VhostUserSetFeatures)?;
+
+        // Identify if protocol features are supported by the slave.
+        let mut acked_features = 0;
+        if avail_features & VhostUserVirtioFeatures::PROTOCOL_FEATURES.bits() != 0 {
+            acked_features |= VhostUserVirtioFeatures::PROTOCOL_FEATURES.bits();
+
+            let mut protocol_features = vhost_user_blk
+                .get_protocol_features()
+                .map_err(Error::VhostUserGetProtocolFeatures)?;
+            protocol_features |= VhostUserProtocolFeatures::MQ;
+            protocol_features &= !VhostUserProtocolFeatures::INFLIGHT_SHMFD;
+            vhost_user_blk
+                .set_protocol_features(protocol_features)
+                .map_err(Error::VhostUserSetProtocolFeatures)?;
+        }
+
+        let config_len = mem::size_of::<virtio_blk_config>();
+        let mut config_space: Vec<u8> = vec![0u8; config_len as usize];
+
+        let queue_num_offset = offset_of!(virtio_blk_config, num_queues);
+        // only setnum_queues value.
+        config_space[queue_num_offset] = vu_cfg.num_queues as u8;
+
+        Ok(Blk {
+            vhost_user_blk,
+            kill_evt,
+            avail_features,
+            acked_features,
+            config_space,
+            queue_sizes: vec![vu_cfg.queue_size; vu_cfg.num_queues],
+        })
+    }
+}
+
+impl Drop for Blk {
+    fn drop(&mut self) {
+        if let Err(_e) = self.kill_evt.write(1) {
+            error!("failed to kill vhost-user-blk with error {}", _e);
+        }
+    }
+}
+
+impl VirtioDevice for Blk {
+    fn device_type(&self) -> u32 {
+        VirtioDeviceType::TYPE_BLOCK as u32
+    }
+
+    fn queue_max_sizes(&self) -> &[u16] {
+        &self.queue_sizes
+    }
+
+    fn features(&self, page: u32) -> u32 {
+        match page {
+            0 => self.avail_features as u32,
+            1 => (self.avail_features >> 32) as u32,
+            _ => {
+                warn!("Received request for unknown features page: {}", page);
+                0u32
+            }
+        }
+    }
+
+    fn ack_features(&mut self, page: u32, value: u32) {
+        let mut v = match page {
+            0 => u64::from(value),
+            1 => u64::from(value) << 32,
+            _ => {
+                warn!("Cannot acknowledge unknown features page: {}", page);
+                0u64
+            }
+        };
+
+        // Check if the guest is ACK'ing a feature that we didn't claim to have.
+        let unrequested_features = v & !self.avail_features;
+        if unrequested_features != 0 {
+            warn!("Received acknowledge request for unknown feature: {:x}", v);
+            // Don't count these features as acked.
+            v &= !unrequested_features;
+        }
+        self.acked_features |= v;
+    }
+
+    fn read_config(&self, offset: u64, mut data: &mut [u8]) {
+        let config_len = self.config_space.len() as u64;
+        if offset >= config_len {
+            error!("Failed to read config space");
+            return;
+        }
+        if let Some(end) = offset.checked_add(data.len() as u64) {
+            // This write can't fail, offset and end are checked against config_len.
+            data.write_all(&self.config_space[offset as usize..cmp::min(end, config_len) as usize])
+                .unwrap();
+        }
+    }
+
+    fn write_config(&mut self, offset: u64, data: &[u8]) {
+        let data_len = data.len() as u64;
+        let config_len = self.config_space.len() as u64;
+        if offset + data_len > config_len {
+            error!("Failed to write config space");
+            return;
+        }
+        let (_, right) = self.config_space.split_at_mut(offset as usize);
+        right.copy_from_slice(&data[..]);
+    }
+
+    fn activate(
+        &mut self,
+        mem: Arc<RwLock<GuestMemoryMmap>>,
+        interrupt_cb: Arc<VirtioInterrupt>,
+        queues: Vec<Queue>,
+        queue_evts: Vec<EventFd>,
+    ) -> ActivateResult {
+        let handler_kill_evt = self
+            .kill_evt
+            .try_clone()
+            .map_err(|_| ActivateError::CloneKillEventFd)?;
+
+        let vu_interrupt_list = setup_vhost_user(
+            &mut self.vhost_user_blk,
+            &mem.read().unwrap(),
+            queues,
+            queue_evts,
+            self.acked_features,
+        )
+        .map_err(ActivateError::VhostUserBlkSetup)?;
+
+        let mut handler = VhostUserEpollHandler::<SlaveReqHandler>::new(VhostUserEpollConfig {
+            interrupt_cb,
+            kill_evt: handler_kill_evt,
+            vu_interrupt_list,
+            slave_req_handler: None,
+        });
+
+        let handler_result = thread::Builder::new()
+            .name("vhost_user_blk".to_string())
+            .spawn(move || {
+                if let Err(e) = handler.run() {
+                    error!("net worker thread exited with error {:?}!", e);
+                }
+            });
+        if let Err(e) = handler_result {
+            error!("vhost-user blk thread create failed with error {:?}", e);
+        }
+        Ok(())
+    }
+}

vm-virtio/src/vhost_user/mod.rs

@@ -12,11 +12,13 @@ use std::io;
 use vhost_rs::Error as VhostError;
 use vm_memory::Error as MmapError;
 
+pub mod blk;
 pub mod fs;
 mod handler;
 pub mod net;
 pub mod vu_common_ctrl;
 
+pub use self::blk::Blk;
 pub use self::fs::*;
 pub use self::net::Net;
 pub use self::vu_common_ctrl::VhostUserConfig;
@@ -91,5 +93,7 @@ pub enum Error {
     VhostUserSetSlaveRequestFd(vhost_rs::Error),
     /// Invalid used address.
     UsedAddress,
+    /// Invalid features provided from vhost-user backend
+    InvalidFeatures,
 }
 type Result<T> = std::result::Result<T, Error>;