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| author | Christian Krinitsin <mail@krinitsin.com> | 2025-05-30 16:52:07 +0200 |
|---|---|---|
| committer | Christian Krinitsin <mail@krinitsin.com> | 2025-05-30 16:52:17 +0200 |
| commit | 9260319e7411ff8281700a532caa436f40120ec4 (patch) | |
| tree | 2f6bfe5f3458dd49d328d3a9eb508595450adec0 /gitlab/issues_text/target_missing/host_missing/accel_missing/2167 | |
| parent | 225caa38269323af1bfc2daadff5ec8bd930747f (diff) | |
| download | qemu-analysis-9260319e7411ff8281700a532caa436f40120ec4.tar.gz qemu-analysis-9260319e7411ff8281700a532caa436f40120ec4.zip | |
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Diffstat (limited to 'gitlab/issues_text/target_missing/host_missing/accel_missing/2167')
| -rw-r--r-- | gitlab/issues_text/target_missing/host_missing/accel_missing/2167 | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/gitlab/issues_text/target_missing/host_missing/accel_missing/2167 b/gitlab/issues_text/target_missing/host_missing/accel_missing/2167 new file mode 100644 index 000000000..61e5b9393 --- /dev/null +++ b/gitlab/issues_text/target_missing/host_missing/accel_missing/2167 @@ -0,0 +1,40 @@ +The GPIO controllers connected to the emulated PCIe bus via vhost-user can't generate interrupts. +Description of problem: +The problem is related to emulation of GPIO controllers using the vhost-user protocol for GPIO. The problem was detected when using the [vhost-device-gpio](https://github.com/rust-vmm/vhost-device) software. I have described the whole issue in https://github.com/rust-vmm/vhost-device/issues/613 , but it is QEMU related, and therefore I describe it here as well. +The broader context is described in https://stackoverflow.com/questions/75906208/how-to-connect-via-virtio-gui-running-on-host-with-gpio-in-a-qemu-emulated-virtu . +Steps to reproduce: +1. For Debian/testing you need to compile a libgpiod-2.1.1 (I assume that the following is done in the home directory directory of the `dev` user: `/home/dev`): + + ``` + wget https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/snapshot/libgpiod-2.1.tar.gz ; \ + tar -xzf libgpiod-2.1.tar.gz ; \ + cd libgpiod-2.1 ; \ + autoupdate ; \ + ./autogen.sh ; \ + make + ``` + 2. Download the vhost-device-gpio (`git clone https://github.com/rust-vmm/vhost-device.git`) + 3. Build the vhost-device-gpio (in the `vhost-device-gpio` subdirectory) + + ``` + export PATH_TO_LIBGPIOD=/home/dev/libgpiod-2.1 + export SYSTEM_DEPS_LIBGPIOD_NO_PKG_CONFIG=1 + export SYSTEM_DEPS_LIBGPIOD_SEARCH_NATIVE="${PATH_TO_LIBGPIOD}/lib/.libs/" + export SYSTEM_DEPS_LIBGPIOD_LIB=gpiod + export SYSTEM_DEPS_LIBGPIOD_INCLUDE="${PATH_TO_LIBGPIOD}/include/" + cargo build --features "mock_gpio" + ``` + 4. Start vhost-device-gpio: (`LD_LIBRARY_PATH=/home/emb/libgpiod-2.1/lib/.libs/ ./vhost-device-gpio -s /tmp/gpio.sock -l s4`) + 5. Download the Buildroot 2023.11.1 (`wget https://buildroot.org/downloads/buildroot-2023.11.1.tar.xz` in another directory) and unpack it. Buildroot and the main directory of Buildroot tree are denoted by BR if the following description. + 6. Configure BR (run `make qemu_aarch64_virt_defconfig` in the main BR directory, run `make menuconfig` and select external toolchain, `BR2_PACKAGE_LIBGPIOD=y`, `BR2_PACKAGE_LIBGPIOD_TOOLS=y`, run `make linux-menuconfig` and select `CONFIG_GPIO_VIRTIO=m` in the kernel configuration) + 7. Build the Linux and QEMU (run `make` in the BR directory). + 8. Run the emulation in BR/output/images, using the command line given above. + 9. After the virtual machine starts, log in as root and load the driver: `modprobe gpio-virtio` +10. Try to monitor changes of one of the emulated pins: `gpiomon 0 0` +11. You'll get the error message: + + ``` + gpiomon: error waiting for events: No such device + ``` +Additional information: +[0009-enable-F-IRQ-in-virtio-pci.patch](/uploads/39bc04b2d94063ccd539c5cfbc9cd105/0009-enable-F-IRQ-in-virtio-pci.patch) |