feat(vmm): add another serial port dedicated to the serverless protocol

Signed-off-by: Martin Moreira de Jesus <martin.moreira-de-jesus@protonmail.com>
virt-do · Apr 21, 2024 · 839d7e0 · 839d7e0
1 parent f844cff
commit 839d7e0
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Showing 3 changed files with 59 additions and 3 deletions.
diff --git a/src/vmm/src/core/cpu/mod.rs b/src/vmm/src/core/cpu/mod.rs
@@ -17,6 +17,8 @@ mod gdt;
 use gdt::*;
 mod interrupts;
 use interrupts::*;
+
+use super::devices::serial::{CONTROL_SERIAL_PORT, CONTROL_SERIAL_PORT_LAST_REGISTER};
 pub(crate) mod mpspec;
 pub(crate) mod mptable;
 pub(crate) mod msr_index;
@@ -68,15 +70,23 @@ pub(crate) struct Vcpu {
     pub vcpu_fd: VcpuFd,
 
     serial: Arc<Mutex<LumperSerial>>,
+
+    control_serial: Arc<Mutex<LumperSerial>>,
 }
 
 impl Vcpu {
     /// Create a new vCPU.
-    pub fn new(vm_fd: &VmFd, index: u64, serial: Arc<Mutex<LumperSerial>>) -> Result<Self> {
+    pub fn new(
+        vm_fd: &VmFd,
+        index: u64,
+        serial: Arc<Mutex<LumperSerial>>,
+        control_serial: Arc<Mutex<LumperSerial>>,
+    ) -> Result<Self> {
         Ok(Vcpu {
             index,
             vcpu_fd: vm_fd.create_vcpu(index).map_err(Error::KvmIoctl)?,
             serial,
+            control_serial,
         })
     }
 
@@ -249,6 +259,20 @@ impl Vcpu {
                             )
                             .unwrap();
                     }
+                    CONTROL_SERIAL_PORT..=CONTROL_SERIAL_PORT_LAST_REGISTER => {
+                        println!("Control serial port write");
+                        self.control_serial
+                            .lock()
+                            .unwrap()
+                            .serial
+                            .write(
+                                (addr - CONTROL_SERIAL_PORT)
+                                    .try_into()
+                                    .expect("Invalid serial register offset"),
+                                data[0],
+                            )
+                            .unwrap();
+                    }
                     KBD_CMD_IO_ADDR => {
                         if data[0] == KBD_RESET_CMD {
                             info!(?exit_reason, "Guest reset via keyboard controller. Bye!");
@@ -270,6 +294,14 @@ impl Vcpu {
                                 .expect("Invalid serial register offset"),
                         );
                     }
+                    CONTROL_SERIAL_PORT..=CONTROL_SERIAL_PORT_LAST_REGISTER => {
+                        println!("Control serial port write");
+                        data[0] = self.control_serial.lock().unwrap().serial.read(
+                            (addr - CONTROL_SERIAL_PORT)
+                                .try_into()
+                                .expect("Invalid serial register offset"),
+                        );
+                    }
                     _ => {
                         warn!(address = addr, "Unsupported device read at {:x?}", addr);
                     }

diff --git a/src/vmm/src/core/devices/serial.rs b/src/vmm/src/core/devices/serial.rs
@@ -10,6 +10,9 @@ use vmm_sys_util::eventfd::EventFd;
 pub const SERIAL_PORT_BASE: u16 = 0x3f8;
 pub const SERIAL_PORT_LAST_REGISTER: u16 = SERIAL_PORT_BASE + 0x8;
 
+pub const CONTROL_SERIAL_PORT: u16 = 0x2f8;
+pub const CONTROL_SERIAL_PORT_LAST_REGISTER: u16 = CONTROL_SERIAL_PORT + 0x8;
+
 pub struct EventFdTrigger(EventFd);
 
 impl Trigger for EventFdTrigger {

diff --git a/src/vmm/src/core/vmm.rs b/src/vmm/src/core/vmm.rs
@@ -30,6 +30,7 @@ pub struct VMM {
     _tap: Tap,
 
     serial: Arc<Mutex<LumperSerial>>,
+    comm_serial: Arc<Mutex<LumperSerial>>,
     epoll: EpollContext,
 }
 
@@ -65,6 +66,9 @@ impl VMM {
             serial: Arc::new(Mutex::new(
                 LumperSerial::new().map_err(Error::SerialCreation)?,
             )),
+            comm_serial: Arc::new(Mutex::new(
+                LumperSerial::new().map_err(Error::SerialCreation)?,
+            )),
             epoll,
         };
 
@@ -124,6 +128,18 @@ impl VMM {
             )
             .map_err(Error::KvmIoctl)?;
 
+        self.vm_fd
+            .register_irqfd(
+                &self
+                    .comm_serial
+                    .lock()
+                    .unwrap()
+                    .eventfd()
+                    .map_err(Error::IrqRegister)?,
+                3,
+            )
+            .map_err(Error::KvmIoctl)?;
+
         Ok(())
     }
 
@@ -137,8 +153,13 @@ impl VMM {
             .map_err(Error::KvmIoctl)?;
 
         for index in 0..num_vcpus {
-            let vcpu = Vcpu::new(&self.vm_fd, index.into(), Arc::clone(&self.serial))
-                .map_err(Error::Vcpu)?;
+            let vcpu = Vcpu::new(
+                &self.vm_fd,
+                index.into(),
+                Arc::clone(&self.serial),
+                Arc::clone(&self.comm_serial),
+            )
+            .map_err(Error::Vcpu)?;
 
             // Set CPUID.
             let mut vcpu_cpuid = base_cpuid.clone();