vfio_user: Always generate an error for commands

Any error from the backend or from the protocol handling code will now
result in an error reply being sent. This is cleanly achieved by
splitting the command handling out into its own method and using the
Rust Result<> based error handling to trigger the generation of the
error reply.

Signed-off-by: Rob Bradford <robert.bradford@intel.com>
This commit is contained in:
Rob Bradford 2023-02-14 12:01:17 +00:00 committed by Bo Chen
parent b072eb454e
commit 10531f052b

View File

@ -272,6 +272,8 @@ pub enum Error {
SocketAccept(#[source] std::io::Error),
#[error("Unsupported command: {0:?}")]
UnsupportedCommand(Command),
#[error("Error from backend: {0:?}")]
Backend(#[source] std::io::Error),
}
impl Client {
@ -854,6 +856,331 @@ impl Server {
})
}
fn handle_command(
&self,
backend: &mut dyn ServerBackend,
stream: &mut UnixStream,
header: Header,
fds: Vec<File>,
) -> Result<(), Error> {
match header.command {
Command::Unknown
| Command::GetRegionIoFds
| Command::DmaRead
| Command::DmaWrite
| Command::UserDirtyPages => {
return Err(Error::UnsupportedCommand(header.command));
}
Command::Version => {
let mut client_version = Version {
header,
..Default::default()
};
stream
.read_exact(&mut client_version.as_mut_slice()[size_of::<Header>()..])
.map_err(Error::StreamRead)?;
let mut raw_version_data = Vec::new();
raw_version_data.resize(header.message_size as usize - size_of::<Version>(), 0u8);
stream
.read_exact(&mut raw_version_data)
.map_err(Error::StreamRead)?;
let version_data = CString::from_vec_with_nul(raw_version_data)
.unwrap()
.to_string_lossy()
.into_owned();
let client_capabilities: Capabilities =
serde_json::from_str(&version_data).map_err(Error::DeserializeCapabilites)?;
info!(
"Received client version: major = {} minor = {} capabilities = {:?}",
client_version.major, client_version.minor, client_capabilities
);
let version = Version {
header: Header {
message_id: client_version.header.message_id,
command: Command::Version,
flags: HeaderFlags::Reply as u32,
message_size: (size_of::<Version>() + version_data.len() + 1) as u32,
..Default::default()
},
major: 0,
minor: 1,
};
let server_capabilities = Capabilities::default();
let version_data = serde_json::to_string(&server_capabilities)
.map_err(Error::SerializeCapabilites)?;
let version_data = CString::new(version_data.as_bytes()).unwrap();
let bufs = vec![
IoSlice::new(version.as_slice()),
IoSlice::new(version_data.as_bytes_with_nul()),
];
// TODO: Use write_all_vectored() when ready
let _ = stream.write_vectored(&bufs).map_err(Error::StreamWrite)?;
info!(
"Sent server version: major = {} minor = {} capabilities = {:?}",
version.major, version.minor, server_capabilities
);
}
Command::DmaMap => {
let mut cmd = DmaMap {
header,
..Default::default()
};
stream
.read_exact(&mut cmd.as_mut_slice()[size_of::<Header>()..])
.map_err(Error::StreamRead)?;
backend
.dma_map(
DmaMapFlags::from_bits_truncate(cmd.flags),
cmd.offset,
cmd.address,
cmd.size,
Some(&fds[0]),
)
.map_err(Error::Backend)?;
let reply = Header {
message_id: cmd.header.message_id,
command: Command::DmaMap,
flags: HeaderFlags::Reply as u32,
message_size: size_of::<Header>() as u32,
..Default::default()
};
stream
.write_all(reply.as_slice())
.map_err(Error::StreamWrite)?;
}
Command::DmaUnmap => {
let mut cmd = DmaUnmap {
header,
..Default::default()
};
stream
.read_exact(&mut cmd.as_mut_slice()[size_of::<Header>()..])
.map_err(Error::StreamRead)?;
backend
.dma_unmap(
DmaUnmapFlags::from_bits_truncate(cmd.flags),
cmd.address,
cmd.size,
)
.map_err(Error::Backend)?;
let reply = DmaUnmap {
header: Header {
message_id: cmd.header.message_id,
command: Command::DmaUnmap,
flags: HeaderFlags::Reply as u32,
message_size: size_of::<Header>() as u32,
..Default::default()
},
argsz: cmd.argsz,
flags: cmd.flags,
address: cmd.address,
size: cmd.size,
};
stream
.write_all(reply.as_slice())
.map_err(Error::StreamWrite)?;
}
Command::DeviceGetInfo => {
let mut cmd = DeviceGetInfo {
header,
..Default::default()
};
stream
.read_exact(&mut cmd.as_mut_slice()[size_of::<Header>()..])
.map_err(Error::StreamRead)?;
let reply = DeviceGetInfo {
header: Header {
message_id: cmd.header.message_id,
command: Command::DeviceGetInfo,
flags: HeaderFlags::Reply as u32,
message_size: size_of::<DeviceGetInfo>() as u32,
..Default::default()
},
argsz: size_of::<DeviceGetInfo>() as u32,
flags: VFIO_DEVICE_FLAGS_PCI
| if self.resettable {
VFIO_DEVICE_FLAGS_RESET
} else {
0
},
num_regions: self.regions.len() as u32,
num_irqs: self.irqs.len() as u32,
};
stream
.write_all(reply.as_slice())
.map_err(Error::StreamWrite)?;
}
Command::DeviceGetRegionInfo => {
let mut cmd = DeviceGetRegionInfo {
header,
..Default::default()
};
stream
.read_exact(&mut cmd.as_mut_slice()[size_of::<Header>()..])
.map_err(Error::StreamRead)?;
let reply = DeviceGetRegionInfo {
header: Header {
message_id: cmd.header.message_id,
command: Command::DeviceGetRegionInfo,
flags: HeaderFlags::Reply as u32,
message_size: size_of::<DeviceGetRegionInfo>() as u32,
..Default::default()
},
region_info: self.regions[cmd.region_info.index as usize],
};
stream
.write_all(reply.as_slice())
.map_err(Error::StreamWrite)?;
}
Command::GetIrqInfo => {
let mut cmd = GetIrqInfo {
header,
..Default::default()
};
stream
.read_exact(&mut cmd.as_mut_slice()[size_of::<Header>()..])
.map_err(Error::StreamRead)?;
let irq = &self.irqs[cmd.index as usize];
let reply = GetIrqInfo {
header: Header {
message_id: cmd.header.message_id,
command: Command::GetIrqInfo,
flags: HeaderFlags::Reply as u32,
message_size: size_of::<GetIrqInfo>() as u32,
..Default::default()
},
argsz: (size_of::<GetIrqInfo>() - size_of::<Header>()) as u32,
index: irq.index,
flags: irq.flags,
count: irq.count,
};
stream
.write_all(reply.as_slice())
.map_err(Error::StreamWrite)?;
}
Command::SetIrqs => {
let mut cmd = SetIrqs {
header,
..Default::default()
};
stream
.read_exact(&mut cmd.as_mut_slice()[size_of::<Header>()..])
.map_err(Error::StreamRead)?;
backend
.set_irqs(cmd.index, cmd.flags, cmd.start, cmd.count, fds)
.map_err(Error::Backend)?;
let reply = Header {
message_id: cmd.header.message_id,
command: Command::SetIrqs,
flags: HeaderFlags::Reply as u32,
message_size: size_of::<Header>() as u32,
..Default::default()
};
stream
.write_all(reply.as_slice())
.map_err(Error::StreamWrite)?;
}
Command::RegionRead => {
let mut cmd = RegionAccess {
header,
..Default::default()
};
stream
.read_exact(&mut cmd.as_mut_slice()[size_of::<Header>()..])
.map_err(Error::StreamRead)?;
let (region, offset, count) = (cmd.region, cmd.offset, cmd.count);
let mut data = vec![0u8; count as usize];
backend
.region_read(region, offset, &mut data)
.map_err(Error::Backend)?;
let reply = RegionAccess {
header: Header {
message_id: cmd.header.message_id,
command: Command::RegionRead,
flags: HeaderFlags::Reply as u32,
message_size: size_of::<RegionAccess>() as u32,
..Default::default()
},
region,
offset,
count,
};
stream
.write_all(reply.as_slice())
.map_err(Error::StreamWrite)?;
stream.write_all(&data).map_err(Error::StreamWrite)?;
}
Command::RegionWrite => {
let mut cmd = RegionAccess {
header,
..Default::default()
};
stream
.read_exact(&mut cmd.as_mut_slice()[size_of::<Header>()..])
.map_err(Error::StreamRead)?;
let (region, offset, count) = (cmd.region, cmd.offset, cmd.count);
let mut data = vec![0u8; count as usize];
stream.read_exact(&mut data).map_err(Error::StreamRead)?;
backend
.region_write(region, offset, &data)
.map_err(Error::Backend)?;
let reply = RegionAccess {
header: Header {
message_id: cmd.header.message_id,
command: Command::RegionWrite,
flags: HeaderFlags::Reply as u32,
message_size: size_of::<RegionAccess>() as u32,
..Default::default()
},
region,
offset,
count,
};
stream
.write_all(reply.as_slice())
.map_err(Error::StreamWrite)?;
}
Command::DeviceReset => {
backend.reset().map_err(Error::Backend)?;
let reply = Header {
message_id: header.message_id,
command: Command::DeviceReset,
flags: HeaderFlags::Reply as u32,
message_size: size_of::<Header>() as u32,
..Default::default()
};
stream
.write_all(reply.as_slice())
.map_err(Error::StreamWrite)?;
}
}
Ok(())
}
pub fn run(&self, backend: &mut dyn ServerBackend) -> Result<(), Error> {
let (mut stream, _) = self.listener.accept().map_err(Error::SocketAccept)?;
@ -888,376 +1215,18 @@ impl Server {
.map(|fd| unsafe { File::from_raw_fd(*fd) })
.collect();
match header.command {
Command::Unknown
| Command::GetRegionIoFds
| Command::DmaRead
| Command::DmaWrite
| Command::UserDirtyPages => {
return Err(Error::UnsupportedCommand(header.command));
}
Command::Version => {
let mut client_version = Version {
header,
..Default::default()
};
stream
.read_exact(&mut client_version.as_mut_slice()[size_of::<Header>()..])
.map_err(Error::StreamRead)?;
let mut raw_version_data = Vec::new();
raw_version_data
.resize(header.message_size as usize - size_of::<Version>(), 0u8);
stream
.read_exact(&mut raw_version_data)
.map_err(Error::StreamRead)?;
let version_data = CString::from_vec_with_nul(raw_version_data)
.unwrap()
.to_string_lossy()
.into_owned();
let client_capabilities: Capabilities = serde_json::from_str(&version_data)
.map_err(Error::DeserializeCapabilites)?;
info!(
"Received client version: major = {} minor = {} capabilities = {:?}",
client_version.major, client_version.minor, client_capabilities
);
let version = Version {
header: Header {
message_id: client_version.header.message_id,
command: Command::Version,
flags: HeaderFlags::Reply as u32,
message_size: (size_of::<Version>() + version_data.len() + 1) as u32,
..Default::default()
},
major: 0,
minor: 1,
};
let server_capabilities = Capabilities::default();
let version_data = serde_json::to_string(&server_capabilities)
.map_err(Error::SerializeCapabilites)?;
let version_data = CString::new(version_data.as_bytes()).unwrap();
let bufs = vec![
IoSlice::new(version.as_slice()),
IoSlice::new(version_data.as_bytes_with_nul()),
];
// TODO: Use write_all_vectored() when ready
let _ = stream.write_vectored(&bufs).map_err(Error::StreamWrite)?;
info!(
"Sent server version: major = {} minor = {} capabilities = {:?}",
version.major, version.minor, server_capabilities
);
}
Command::DmaMap => {
let mut cmd = DmaMap {
header,
..Default::default()
};
stream
.read_exact(&mut cmd.as_mut_slice()[size_of::<Header>()..])
.map_err(Error::StreamRead)?;
let reply = match backend.dma_map(
DmaMapFlags::from_bits_truncate(cmd.flags),
cmd.offset,
cmd.address,
cmd.size,
Some(&fds[0]),
) {
Ok(()) => Header {
message_id: cmd.header.message_id,
command: Command::DmaMap,
flags: HeaderFlags::Reply as u32,
message_size: size_of::<Header>() as u32,
..Default::default()
},
Err(e) => Header {
message_id: cmd.header.message_id,
command: Command::DmaMap,
flags: HeaderFlags::Error as u32,
message_size: size_of::<Header>() as u32,
error: e.raw_os_error().unwrap_or_default() as u32,
},
};
stream
.write_all(reply.as_slice())
.map_err(Error::StreamWrite)?;
}
Command::DmaUnmap => {
let mut cmd = DmaUnmap {
header,
..Default::default()
};
stream
.read_exact(&mut cmd.as_mut_slice()[size_of::<Header>()..])
.map_err(Error::StreamRead)?;
match backend.dma_unmap(
DmaUnmapFlags::from_bits_truncate(cmd.flags),
cmd.address,
cmd.size,
) {
Ok(()) => {
let reply = DmaUnmap {
header: Header {
message_id: cmd.header.message_id,
command: Command::DmaUnmap,
flags: HeaderFlags::Reply as u32,
message_size: size_of::<Header>() as u32,
..Default::default()
},
argsz: cmd.argsz,
flags: cmd.flags,
address: cmd.address,
size: cmd.size,
};
stream
.write_all(reply.as_slice())
.map_err(Error::StreamWrite)?;
}
Err(e) => {
let reply = Header {
message_id: cmd.header.message_id,
command: Command::DmaUnmap,
flags: HeaderFlags::Error as u32,
message_size: size_of::<Header>() as u32,
error: e.raw_os_error().unwrap_or_default() as u32,
};
stream
.write_all(reply.as_slice())
.map_err(Error::StreamWrite)?;
}
};
}
Command::DeviceGetInfo => {
let mut cmd = DeviceGetInfo {
header,
..Default::default()
};
stream
.read_exact(&mut cmd.as_mut_slice()[size_of::<Header>()..])
.map_err(Error::StreamRead)?;
let reply = DeviceGetInfo {
header: Header {
message_id: cmd.header.message_id,
command: Command::DeviceGetInfo,
flags: HeaderFlags::Reply as u32,
message_size: size_of::<DeviceGetInfo>() as u32,
..Default::default()
},
argsz: size_of::<DeviceGetInfo>() as u32,
flags: VFIO_DEVICE_FLAGS_PCI
| if self.resettable {
VFIO_DEVICE_FLAGS_RESET
} else {
0
},
num_regions: self.regions.len() as u32,
num_irqs: self.irqs.len() as u32,
};
stream
.write_all(reply.as_slice())
.map_err(Error::StreamWrite)?;
}
Command::DeviceGetRegionInfo => {
let mut cmd = DeviceGetRegionInfo {
header,
..Default::default()
};
stream
.read_exact(&mut cmd.as_mut_slice()[size_of::<Header>()..])
.map_err(Error::StreamRead)?;
let reply = DeviceGetRegionInfo {
header: Header {
message_id: cmd.header.message_id,
command: Command::DeviceGetRegionInfo,
flags: HeaderFlags::Reply as u32,
message_size: size_of::<DeviceGetRegionInfo>() as u32,
..Default::default()
},
region_info: self.regions[cmd.region_info.index as usize],
};
stream
.write_all(reply.as_slice())
.map_err(Error::StreamWrite)?;
}
Command::GetIrqInfo => {
let mut cmd = GetIrqInfo {
header,
..Default::default()
};
stream
.read_exact(&mut cmd.as_mut_slice()[size_of::<Header>()..])
.map_err(Error::StreamRead)?;
let irq = &self.irqs[cmd.index as usize];
let reply = GetIrqInfo {
header: Header {
message_id: cmd.header.message_id,
command: Command::GetIrqInfo,
flags: HeaderFlags::Reply as u32,
message_size: size_of::<GetIrqInfo>() as u32,
..Default::default()
},
argsz: (size_of::<GetIrqInfo>() - size_of::<Header>()) as u32,
index: irq.index,
flags: irq.flags,
count: irq.count,
};
stream
.write_all(reply.as_slice())
.map_err(Error::StreamWrite)?;
}
Command::SetIrqs => {
let mut cmd = SetIrqs {
header,
..Default::default()
};
stream
.read_exact(&mut cmd.as_mut_slice()[size_of::<Header>()..])
.map_err(Error::StreamRead)?;
let reply =
match backend.set_irqs(cmd.index, cmd.flags, cmd.start, cmd.count, fds) {
Ok(()) => Header {
message_id: cmd.header.message_id,
command: Command::SetIrqs,
flags: HeaderFlags::Reply as u32,
message_size: size_of::<Header>() as u32,
..Default::default()
},
Err(e) => Header {
message_id: cmd.header.message_id,
command: Command::SetIrqs,
flags: HeaderFlags::Error as u32,
message_size: size_of::<Header>() as u32,
error: e.raw_os_error().unwrap_or_default() as u32,
},
};
stream
.write_all(reply.as_slice())
.map_err(Error::StreamWrite)?;
}
Command::RegionRead => {
let mut cmd = RegionAccess {
header,
..Default::default()
};
stream
.read_exact(&mut cmd.as_mut_slice()[size_of::<Header>()..])
.map_err(Error::StreamRead)?;
let (region, offset, count) = (cmd.region, cmd.offset, cmd.count);
let mut data = vec![0u8; count as usize];
match backend.region_read(region, offset, &mut data) {
Ok(()) => {
let reply = RegionAccess {
header: Header {
message_id: cmd.header.message_id,
command: Command::RegionRead,
flags: HeaderFlags::Reply as u32,
message_size: size_of::<RegionAccess>() as u32,
..Default::default()
},
region,
offset,
count,
};
stream
.write_all(reply.as_slice())
.map_err(Error::StreamWrite)?;
stream.write_all(&data).map_err(Error::StreamWrite)?;
}
Err(e) => {
let reply = Header {
message_id: cmd.header.message_id,
command: Command::RegionRead,
flags: HeaderFlags::Error as u32,
message_size: size_of::<Header>() as u32,
error: e.raw_os_error().unwrap_or_default() as u32,
};
stream
.write_all(reply.as_slice())
.map_err(Error::StreamWrite)?;
}
}
}
Command::RegionWrite => {
let mut cmd = RegionAccess {
header,
..Default::default()
};
stream
.read_exact(&mut cmd.as_mut_slice()[size_of::<Header>()..])
.map_err(Error::StreamRead)?;
let (region, offset, count) = (cmd.region, cmd.offset, cmd.count);
let mut data = vec![0u8; count as usize];
stream.read_exact(&mut data).map_err(Error::StreamRead)?;
match backend.region_write(region, offset, &data) {
Ok(()) => {
let reply = RegionAccess {
header: Header {
message_id: cmd.header.message_id,
command: Command::RegionWrite,
flags: HeaderFlags::Reply as u32,
message_size: size_of::<RegionAccess>() as u32,
..Default::default()
},
region,
offset,
count,
};
stream
.write_all(reply.as_slice())
.map_err(Error::StreamWrite)?;
}
Err(e) => {
let reply = Header {
message_id: cmd.header.message_id,
command: Command::RegionWrite,
flags: HeaderFlags::Error as u32,
message_size: size_of::<Header>() as u32,
error: e.raw_os_error().unwrap_or_default() as u32,
};
stream
.write_all(reply.as_slice())
.map_err(Error::StreamWrite)?;
}
}
}
Command::DeviceReset => {
let reply = match backend.reset() {
Ok(()) => Header {
message_id: header.message_id,
command: Command::DeviceReset,
flags: HeaderFlags::Reply as u32,
message_size: size_of::<Header>() as u32,
..Default::default()
},
Err(e) => Header {
message_id: header.message_id,
command: Command::DeviceReset,
flags: HeaderFlags::Error as u32,
message_size: size_of::<Header>() as u32,
error: e.raw_os_error().unwrap_or_default() as u32,
},
};
stream
.write_all(reply.as_slice())
.map_err(Error::StreamWrite)?;
}
if let Err(e) = self.handle_command(backend, &mut stream, header, fds) {
error!("Error handling command: {:?}: {e}", header.command);
let reply = Header {
message_id: header.message_id,
command: header.command,
flags: HeaderFlags::Error as u32,
message_size: size_of::<Header>() as u32,
error: 0,
};
stream
.write_all(reply.as_slice())
.map_err(Error::StreamWrite)?;
}
}