Re: [PATCH v2 32/32] tests/functional/x86_64: add functional test to exercise vm fd change on reset

["Daniel P. Berrangé" <berrange@redhat.com>]

On Mon, Jan 12, 2026 at 06:52:45PM +0530, Ani Sinha wrote:
> A new functional test is added that exercises the code changes related to
> closing of the old KVM VM file descriptor and opening a new one upon VM reset.
> This normally happens when confidential guests are resetted but for
> non-confidential guests, we use a special machine specific debug/test parameter
> 'x-change-vmfd-on-reset' to enable this behavior.
> Only specific code changes related to re-initialization of SEV-ES, SEV-SNP and
> TDX platforms are not exercized in this test as they require hardware that
> supports running confidential guests.
> 
> Signed-off-by: Ani Sinha <anisinha@redhat.com>
> ---
>  MAINTAINERS                                   |  6 ++
>  tests/functional/x86_64/meson.build           |  1 +
>  .../x86_64/test_vmfd_change_reboot.py         | 75 +++++++++++++++++++
>  3 files changed, 82 insertions(+)
>  create mode 100755 tests/functional/x86_64/test_vmfd_change_reboot.py


> diff --git a/tests/functional/x86_64/test_vmfd_change_reboot.py b/tests/functional/x86_64/test_vmfd_change_reboot.py
> new file mode 100755
> index 0000000000..3b33322880
> --- /dev/null
> +++ b/tests/functional/x86_64/test_vmfd_change_reboot.py
> @@ -0,0 +1,75 @@
> +#!/usr/bin/env python3
> +#
> +# KVM VM file descriptor change on reset test
> +#
> +# Copyright © 2026 Red Hat, Inc.
> +#
> +# Author:
> +#  Ani Sinha <anisinha@redhat.com>
> +#
> +# SPDX-License-Identifier: GPL-2.0-or-later
> +
> +import os
> +from qemu.machine import machine
> +
> +from qemu_test import QemuSystemTest, Asset, exec_command_and_wait_for_pattern
> +from qemu_test import wait_for_console_pattern
> +
> +class KVMGuest(QemuSystemTest):
> +
> +    ASSET_UKI = Asset('https://gitlab.com/anisinha/misc-artifacts/'
> +                      '-/raw/main/uki.x86-64.efi?ref_type=heads',
> +                      'e0f806bd1fa24111312e1fe849d2ee69808d4343930a5'
> +                      'dc8c1688da17c65f576')
> +    ASSET_OVMF = Asset('https://gitlab.com/anisinha/misc-artifacts/'
> +                       '-/raw/main/OVMF.stateless.fd?ref_type=heads',
> +                       '58a4275aafa8774bd6b1540adceae4ea434b8db75b476'
> +                       '11839ff47be88cfcf22')

What is the source of these two binaries - the repo doesn't show any
source code or references ?  Is there no way we can use standard distro
images for this test ?

> +
> +    def common_vm_setup(self):
> +        self.require_accelerator("kvm")
> +
> +        self.vm.set_console()
> +
> +        self.vm.add_args("-accel", "kvm")
> +        self.vm.add_args("-smp", "2")
> +        self.vm.add_args("-cpu", "host")
> +        self.vm.add_args("-m", "2G")
> +        self.vm.add_args("-nographic", "-nodefaults")
> +
> +        self.uki_path = self.ASSET_UKI.fetch()
> +        self.ovmf_path = self.ASSET_OVMF.fetch()
> +
> +    def run_and_check(self):
> +        self.vm.add_args('-kernel', self.uki_path)
> +        self.vm.add_args("-bios", self.ovmf_path)
> +        # enable KVM VMFD change on reset for a non-coco VM
> +        self.vm.add_args("-machine", "q35,x-change-vmfd-on-reset=on")
> +        # enable tracing
> +        self.vm.add_args("-d", "trace:kvm_reset_vmfd")
> +
> +        try:
> +            self.vm.launch()
> +        except machine.VMLaunchFailure as e:
> +            raise e
> +
> +        self.log.info('VM launched')
> +        console_pattern = 'bash-5.1#'
> +        wait_for_console_pattern(self, console_pattern)
> +        self.log.info('VM ready with a bash prompt')
> +
> +        exec_command_and_wait_for_pattern(self, '/usr/sbin/reboot -f',
> +                                          'reboot: machine restart')
> +        console_pattern = '# --- Hello world ---'
> +        wait_for_console_pattern(self, console_pattern)
> +        self.vm.shutdown()
> +        self.assertRegex(self.vm.get_log(),
> +                         r'kvm_reset_vmfd \nINFO: virtual machine accel file '
> +                         'descriptor has changed')
> +
> +    def test_vmfd_change_on_reset(self):
> +        self.common_vm_setup()
> +        self.run_and_check()
> +
> +if __name__ == '__main__':
> +    QemuSystemTest.main()
> -- 
> 2.42.0
> 
> 

With regards,
Daniel
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