Try reading block device. Share queues and buffers with host.
For now the host will be able to both read and write all parts of the
virtqueues, but the buffers themselves will be copied so the host can't
write over buffer it shouldn't.
Bug: 237250092
Bug: 261439403
Test: Ran pVM firmware manually with a block device
Change-Id: I38d965e92342e86e39b5cc8b9cf32ad3bc90417b
diff --git a/pvmfw/src/virtio/pci.rs b/pvmfw/src/virtio/pci.rs
new file mode 100644
index 0000000..f9d36c6
--- /dev/null
+++ b/pvmfw/src/virtio/pci.rs
@@ -0,0 +1,73 @@
+// Copyright 2022, The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Functions to scan the PCI bus for VirtIO devices.
+
+use super::hal::HalImpl;
+use crate::{entry::RebootReason, memory::MemoryTracker};
+use fdtpci::{PciError, PciInfo};
+use log::{debug, error, info};
+use virtio_drivers::{
+ device::blk::VirtIOBlk,
+ transport::{
+ pci::{bus::PciRoot, virtio_device_type, PciTransport},
+ DeviceType, Transport,
+ },
+};
+
+/// Maps the CAM and BAR range in the page table and MMIO guard.
+pub fn map_mmio(pci_info: &PciInfo, memory: &mut MemoryTracker) -> Result<(), RebootReason> {
+ memory.map_mmio_range(pci_info.cam_range.clone()).map_err(|e| {
+ error!("Failed to map PCI CAM: {}", e);
+ RebootReason::InternalError
+ })?;
+
+ memory
+ .map_mmio_range(pci_info.bar_range.start as usize..pci_info.bar_range.end as usize)
+ .map_err(|e| {
+ error!("Failed to map PCI MMIO range: {}", e);
+ RebootReason::InternalError
+ })?;
+
+ Ok(())
+}
+
+/// Finds VirtIO PCI devices.
+pub fn find_virtio_devices(pci_root: &mut PciRoot) -> Result<(), PciError> {
+ for (device_function, info) in pci_root.enumerate_bus(0) {
+ let (status, command) = pci_root.get_status_command(device_function);
+ debug!(
+ "Found PCI device {} at {}, status {:?} command {:?}",
+ info, device_function, status, command
+ );
+ if let Some(virtio_type) = virtio_device_type(&info) {
+ debug!(" VirtIO {:?}", virtio_type);
+ let mut transport = PciTransport::new::<HalImpl>(pci_root, device_function).unwrap();
+ info!(
+ "Detected virtio PCI device with device type {:?}, features {:#018x}",
+ transport.device_type(),
+ transport.read_device_features(),
+ );
+ if virtio_type == DeviceType::Block {
+ let mut blk =
+ VirtIOBlk::<HalImpl, _>::new(transport).expect("failed to create blk driver");
+ info!("Found {} KiB block device.", blk.capacity() * 512 / 1024);
+ let mut data = [0; 512];
+ blk.read_block(0, &mut data).expect("Failed to read block device");
+ }
+ }
+ }
+
+ Ok(())
+}