From 462fcfdf751307703e174aca28008827f4a1c282 Mon Sep 17 00:00:00 2001
From: Kroese <kroese@users.noreply.github.com>
Date: Fri, 14 Mar 2025 06:57:32 +0100
Subject: [PATCH] feat: Support file sharing (#198)

---
 readme.md     | 17 +++++++++++++++++
 src/config.sh |  9 ++++++++-
 src/proc.sh   | 27 ++++++++++++++++++++++++++-
 3 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/readme.md b/readme.md
index 6d8a204..ec463a3 100644
--- a/readme.md
+++ b/readme.md
@@ -276,6 +276,23 @@ kubectl apply -f https://raw.githubusercontent.com/qemus/qemu-arm/refs/heads/mas
     - /dev/bus/usb
   ```
 
+### How do I share files with the host?
+
+  To share files with the host, first ensure that your guest OS has `9pfs` support compiled in or available as a kernel module. If so, add the following volume to your compose file:
+
+  ```yaml
+  volumes:
+    -  ./example:/shared
+  ```
+
+  Then start the container and execute the following command in the guest:
+
+  ```shell
+  mount -t 9p -o trans=virtio shared /mnt/example
+  ```
+
+  Now the `./example` directory on the host will be available as `/mnt/example` in the guest.
+
 ### How can I provide custom arguments to QEMU?
 
   You can create the `ARGUMENTS` environment variable to provide additional arguments to QEMU at runtime:
diff --git a/src/config.sh b/src/config.sh
index 2a20a84..6dbcba6 100644
--- a/src/config.sh
+++ b/src/config.sh
@@ -17,8 +17,15 @@ MAC_OPTS="-machine type=${MACHINE},secure=${SECURE},dump-guest-core=off${KVM_OPT
 [ -n "$UUID" ] && MAC_OPTS="$MAC_OPTS -uuid $UUID"
 DEV_OPTS="-object rng-random,id=objrng0,filename=/dev/urandom"
 DEV_OPTS+=" -device virtio-rng-pci,rng=objrng0,id=rng0,bus=pcie.0"
-[[ "${BOOT_MODE,,}" != "windows"* ]] && DEV_OPTS+=" -device virtio-balloon-pci,id=balloon0,bus=pcie.0"
 
+if [[ "${BOOT_MODE,,}" != "windows"* ]]; then
+  DEV_OPTS+=" -device virtio-balloon-pci,id=balloon0,bus=pcie.0"
+  if [ -d "/shared" ]; then
+    DEV_OPTS+=" -fsdev local,id=fsdev0,path=/shared,security_model=none"
+    DEV_OPTS+=" -device virtio-9p-pci,id=fs0,fsdev=fsdev0,mount_tag=shared"
+  fi
+fi
+  
 ARGS="$DEF_OPTS $CPU_OPTS $RAM_OPTS $MAC_OPTS $DISPLAY_OPTS $MON_OPTS $SERIAL_OPTS ${USB_OPTS:-} $NET_OPTS $DISK_OPTS $BOOT_OPTS $DEV_OPTS $ARGUMENTS"
 ARGS=$(echo "$ARGS" | sed 's/\t/ /g' | tr -s ' ')
 
diff --git a/src/proc.sh b/src/proc.sh
index 784a822..de2b7bb 100644
--- a/src/proc.sh
+++ b/src/proc.sh
@@ -24,7 +24,32 @@ if [[ "$CPU" == "Rockchip RK3588"* ]] && [[ "$CORES" == "8" ]]; then
   [ -z "$CPU_PIN" ] && CPU_PIN="4,5,6,7"
 fi
 
- if [[ "${ARCH,,}" != "arm64" ]]; then
+MSRS="/sys/module/kvm/parameters/ignore_msrs"
+if [ -e "$MSRS" ]; then
+  result=$(<"$MSRS")
+  if [[ "$result" == "0" ]] || [[ "${result^^}" == "N" ]]; then
+    echo 1 | tee "$MSRS" > /dev/null 2>&1 || true
+  fi
+fi
+
+CLOCKSOURCE="tsc"
+[[ "${ARCH,,}" == "arm64" ]] && CLOCKSOURCE="arch_sys_counter"
+CLOCK="/sys/devices/system/clocksource/clocksource0/current_clocksource"
+
+if [ ! -f "$CLOCK" ]; then
+  warn "file \"$CLOCK\" cannot not found?"
+else
+  result=$(<"$CLOCK")
+  case "${result,,}" in
+    "${CLOCKSOURCE,,}" ) ;;
+    "kvm-clock" ) info "Nested KVM virtualization detected.." ;;
+    "hyperv_clocksource_tsc_page" ) info "Nested Hyper-V virtualization detected.." ;;
+    "hpet" ) warn "unsupported clock source detected: '$result'. Please set host clock source to '$CLOCKSOURCE'" ;;
+    *) warn "unexpected clock source detected: '$result'. Please set host clock source to '$CLOCKSOURCE'" ;;
+  esac
+fi
+
+if [[ "${ARCH,,}" != "arm64" ]]; then
   KVM="N"
   warn "your CPU architecture is ${ARCH^^} and cannot provide KVM acceleration for ARM64 instructions, this will cause a major loss of performance."
 fi