Add VhostVdpa trait

Add new VhostVdpa trait to handle vhost-vdpa devices and a new
vhost-vdpa building feature.

vhost-vdpa devices is based on vhost backend, for this reason
VhostVdpa trait requires VhostBackend.

Signed-off-by: Stefano Garzarella <[email protected]>

Author: stefano-garzarella

Cargo.toml

@@ -14,6 +14,7 @@ edition = "2018"
 default = []
 vhost-vsock = []
 vhost-kern = []
+vhost-vdpa = ["vhost-kern"]
 vhost-user = []
 vhost-user-master = ["vhost-user"]
 vhost-user-slave = ["vhost-user"]

coverage_config_x86_64.json

@@ -1 +1 @@
-{"coverage_score": 80.8, "exclude_path": "src/vhost_kern/", "crate_features": "vhost-user-master,vhost-user-slave"}
+{"coverage_score": 80.2, "exclude_path": "src/vhost_kern/", "crate_features": "vhost-user-master,vhost-user-slave"}

src/lib.rs

@@ -40,6 +40,8 @@ extern crate vmm_sys_util;
 mod backend;
 pub use backend::*;
 
+#[cfg(feature = "vhost-vdpa")]
+pub mod vdpa;
 #[cfg(feature = "vhost-kern")]
 pub mod vhost_kern;
 #[cfg(feature = "vhost-user")]

src/vdpa.rs

@@ -0,0 +1,68 @@
+// Copyright (C) 2021 Red Hat, Inc. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0 or BSD-3-Clause
+
+//! Trait to control vhost-vdpa backend drivers.
+
+use vmm_sys_util::eventfd::EventFd;
+
+use crate::backend::VhostBackend;
+use crate::Result;
+
+/// vhost vdpa IOVA range
+pub struct VhostVdpaIovaRange {
+    /// First address that can be mapped by vhost-vDPA.
+    pub first: u64,
+    /// Last address that can be mapped by vhost-vDPA.
+    pub last: u64,
+}
+
+/// Trait to control vhost-vdpa backend drivers.
+pub trait VhostVdpa: VhostBackend {
+    /// Get the device id.
+    /// The device ids follow the same definition of the device id defined in virtio-spec.
+    fn get_device_id(&self) -> Result<u32>;
+
+    /// Get the status.
+    /// The status bits follow the same definition of the device status defined in virtio-spec.
+    fn get_status(&self) -> Result<u8>;
+
+    /// Set the status.
+    /// The status bits follow the same definition of the device status defined in virtio-spec.
+    ///
+    /// # Arguments
+    /// * `status` - Status bits to set
+    fn set_status(&self, status: u8) -> Result<()>;
+
+    /// Get the device configuration.
+    ///
+    /// # Arguments
+    /// * `offset` - Offset in the device configuration space
+    /// * `buffer` - Buffer for configuration data
+    fn get_config(&self, offset: u32, buffer: &mut [u8]) -> Result<()>;
+
+    /// Set the device configuration.
+    ///
+    /// # Arguments
+    /// * `offset` - Offset in the device configuration space
+    /// * `buffer` - Buffer for configuration data
+    fn set_config(&self, offset: u32, buffer: &[u8]) -> Result<()>;
+
+    /// Set the status for a given vring.
+    ///
+    /// # Arguments
+    /// * `queue_index` - Index of the queue to enable/disable.
+    /// * `enabled` - true to enable the vring, false to disable it.
+    fn set_vring_enable(&self, queue_index: usize, enabled: bool) -> Result<()>;
+
+    /// Get the maximum number of descriptors in the vring supported by the device.
+    fn get_vring_num(&self) -> Result<u16>;
+
+    /// Set the eventfd to trigger when device configuration change.
+    ///
+    /// # Arguments
+    /// * `fd` - EventFd to trigger.
+    fn set_config_call(&self, fd: &EventFd) -> Result<()>;
+
+    /// Get the valid I/O virtual addresses range supported by the device.
+    fn get_iova_range(&self) -> Result<VhostVdpaIovaRange>;
+}