From c94e55d45a7ca15e294095643202107d1d6c69a7 Mon Sep 17 00:00:00 2001
From: Pavel Mores <pmores@redhat.com>
Date: Mon, 25 Mar 2024 11:10:37 +0100
Subject: [PATCH] runtime-rs: make QemuCmdLine own vsock file descriptor

Make file descriptors to be passed to qemu owned by QemuCmdLine.  See
commit 52958f17cd for more explanation.

Signed-off-by: Pavel Mores <pmores@redhat.com>
---
 .../hypervisor/src/qemu/cmdline_generator.rs       | 12 ++++++------
 src/runtime-rs/crates/hypervisor/src/qemu/inner.rs | 14 ++++----------
 2 files changed, 10 insertions(+), 16 deletions(-)

diff --git a/src/runtime-rs/crates/hypervisor/src/qemu/cmdline_generator.rs b/src/runtime-rs/crates/hypervisor/src/qemu/cmdline_generator.rs
index 2a1eddb064..e6e63cff41 100644
--- a/src/runtime-rs/crates/hypervisor/src/qemu/cmdline_generator.rs
+++ b/src/runtime-rs/crates/hypervisor/src/qemu/cmdline_generator.rs
@@ -13,7 +13,7 @@ use std::collections::HashMap;
 use std::fmt::Display;
 use std::fs::{read_to_string, File};
 use std::os::fd::AsRawFd;
-use std::os::unix::io::RawFd;
+use tokio;
 
 // These should have been called MiB and GiB for better readability but the
 // more fitting names unfortunately generate linter warnings.
@@ -811,13 +811,13 @@ impl ToQemuParams for DeviceVirtioBlk {
 
 struct VhostVsock {
     bus_type: VirtioBusType,
-    vhostfd: RawFd,
+    vhostfd: tokio::fs::File,
     guest_cid: u32,
     disable_modern: bool,
 }
 
 impl VhostVsock {
-    fn new(vhostfd: RawFd, guest_cid: u32, bus_type: VirtioBusType) -> VhostVsock {
+    fn new(vhostfd: tokio::fs::File, guest_cid: u32, bus_type: VirtioBusType) -> VhostVsock {
         VhostVsock {
             bus_type,
             vhostfd,
@@ -840,7 +840,7 @@ impl ToQemuParams for VhostVsock {
         if self.disable_modern {
             params.push("disable-modern=true".to_owned());
         }
-        params.push(format!("vhostfd={}", self.vhostfd));
+        params.push(format!("vhostfd={}", self.vhostfd.as_raw_fd()));
         params.push(format!("guest-cid={}", self.guest_cid));
 
         Ok(vec!["-device".to_owned(), params.join(",")])
@@ -1198,8 +1198,8 @@ impl<'a> QemuCmdLine<'a> {
         }
     }
 
-    pub fn add_vsock(&mut self, vhostfd: RawFd, guest_cid: u32) -> Result<()> {
-        clear_cloexec(vhostfd).context("clearing O_CLOEXEC failed on vsock fd")?;
+    pub fn add_vsock(&mut self, vhostfd: tokio::fs::File, guest_cid: u32) -> Result<()> {
+        clear_cloexec(vhostfd.as_raw_fd()).context("clearing O_CLOEXEC failed on vsock fd")?;
 
         let mut vhost_vsock_pci = VhostVsock::new(vhostfd, guest_cid, self.bus_type());
 
diff --git a/src/runtime-rs/crates/hypervisor/src/qemu/inner.rs b/src/runtime-rs/crates/hypervisor/src/qemu/inner.rs
index 31fc6ff650..16da0bdafb 100644
--- a/src/runtime-rs/crates/hypervisor/src/qemu/inner.rs
+++ b/src/runtime-rs/crates/hypervisor/src/qemu/inner.rs
@@ -17,7 +17,6 @@ use kata_types::{
 };
 use persist::sandbox_persist::Persist;
 use std::collections::HashMap;
-use std::os::unix::io::AsRawFd;
 use std::path::Path;
 use std::process::Stdio;
 use tokio::{
@@ -65,15 +64,11 @@ impl QemuInner {
         info!(sl!(), "Starting QEMU VM");
         let netns = self.netns.clone().unwrap_or_default();
 
+        // CAUTION: since 'cmdline' contains file descriptors that have to stay
+        // open until spawn() is called to launch qemu later in this function,
+        // 'cmdline' has to live at least until spawn() is called
         let mut cmdline = QemuCmdLine::new(&self.id, &self.config)?;
 
-        // CAUTION: File descriptors that are passed to QEMU must stay open until the QEMU process
-        // is started and closed afterwards. This is achieved by collecting them in _fds_for_qemu.
-        // It is mandatory for _fds_for_qemu to last until the QEMU process is forked. Leave it
-        // in the outer scope of this function for this to happen. The files in _fds_for_qemu
-        // should not be used in any way.
-        let mut _fds_for_qemu: Vec<std::fs::File> = Vec::new();
-
         for device in &mut self.devices {
             match device {
                 DeviceType::ShareFs(share_fs_dev) => {
@@ -87,8 +82,7 @@ impl QemuInner {
                 }
                 DeviceType::Vsock(vsock_dev) => {
                     let fd = vsock_dev.init_config().await?;
-                    cmdline.add_vsock(fd.as_raw_fd(), vsock_dev.config.guest_cid)?;
-                    _fds_for_qemu.push(fd.into_std().await);
+                    cmdline.add_vsock(fd, vsock_dev.config.guest_cid)?;
                 }
                 DeviceType::Block(block_dev) => {
                     if block_dev.config.path_on_host == self.config.boot_info.initrd {