On 7/22/22 18:23, Daniel P. Berrangé wrote:
Normally when an UEFI firmware is marked as read-only, an associated NVRAM file will be created. Some builds of UEFI firmware, however, wish to remain stateless and so will be read-only, but never have any NVRAM file. To represent this concept a 'stateless' tristate bool attribute is introduced on the <loader/> element.
There are rather a large number of permutations to consider.
With default firmware selection
* <os/>
=> Historic default, no change
* <os> <loader stateless='yes'/> </os>
=> Explicit version of historic default, no change
* <os> <loader stateless='no'/> </os>
=> Invalid, bios is always stateless
With manual legacy BIOS selection
* <os> <loader>/path/to/seabios</loader> ... </os>
=> Historic default, no change
* <os> <loader stateless='yes'>/path/to/seabios</loader> ... </os>
=> Explicit version of historic default, no change
* <os> <loader stateless='no'>/path/to/seabios</loader> ... </os>
=> Invalid, bios is always stateless
With manual UEFI selection
* <os> <loader type='pflash'>/path/to/edk2</loader> ... </os>
=> Historic default, no change
* <os> <loader type='pflash' stateless='yes'>/path/to/edk2</loader> ... </os>
=> Skip auto-filling NVRAM / template
* <os> <loader type='pflash' stateless='no'>/path/to/edk2</loader> ... </os>
=> Explicit version of historic default, no change
With automatic firmware selection
* <os firmware='bios'/>
=> Historic default, no change
* <os firmware='bios'> <loader stateless='yes'/> </os>
=> Explicit version of historic default, no change
* <os firmware='bios'> <loader stateless='no'/> </os>
=> Invalid, bios is always stateless
* <os firmware='uefi'/>
=> Historic default, no change
* <os firmware='uefi'> <loader stateless='yes'/> </os>
=> Skip auto-filling NVRAM / template
* <os firmware='uefi'> <loader stateless='no'/> </os>
=> Explicit version of historic default, no change
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> --- docs/formatdomain.rst | 9 ++++- src/conf/domain_conf.c | 9 +++++ src/conf/domain_conf.h | 1 + src/conf/domain_validate.c | 26 ++++++++++++++ src/conf/schemas/domaincommon.rng | 5 +++ ...-auto-bios-not-stateless.x86_64-latest.err | 1 + .../firmware-auto-bios-not-stateless.xml | 18 ++++++++++ ...are-auto-bios-stateless.x86_64-latest.args | 32 +++++++++++++++++ .../firmware-auto-bios-stateless.xml | 18 ++++++++++ .../firmware-manual-bios-not-stateless.err | 1 + .../firmware-manual-bios-not-stateless.xml | 15 ++++++++ .../firmware-manual-bios-stateless.args | 30 ++++++++++++++++ .../firmware-manual-bios-stateless.xml | 15 ++++++++ ...nual-efi-nvram-stateless.x86_64-latest.err | 1 + .../firmware-manual-efi-nvram-stateless.xml | 21 ++++++++++++ ...nvram-template-stateless.x86_64-latest.err | 1 + ...re-manual-efi-nvram-template-stateless.xml | 19 +++++++++++ tests/qemuxml2argvtest.c | 8 +++++ ...ware-auto-bios-stateless.x86_64-latest.xml | 34 +++++++++++++++++++ .../firmware-manual-bios-stateless.xml | 25 ++++++++++++++ .../firmware-manual-bios.xml | 25 ++++++++++++++ tests/qemuxml2xmltest.c | 3 ++ 22 files changed, 316 insertions(+), 1 deletion(-) create mode 100644 tests/qemuxml2argvdata/firmware-auto-bios-not-stateless.x86_64-latest.err create mode 100644 tests/qemuxml2argvdata/firmware-auto-bios-not-stateless.xml create mode 100644 tests/qemuxml2argvdata/firmware-auto-bios-stateless.x86_64-latest.args create mode 100644 tests/qemuxml2argvdata/firmware-auto-bios-stateless.xml create mode 100644 tests/qemuxml2argvdata/firmware-manual-bios-not-stateless.err create mode 100644 tests/qemuxml2argvdata/firmware-manual-bios-not-stateless.xml create mode 100644 tests/qemuxml2argvdata/firmware-manual-bios-stateless.args create mode 100644 tests/qemuxml2argvdata/firmware-manual-bios-stateless.xml create mode 100644 tests/qemuxml2argvdata/firmware-manual-efi-nvram-stateless.x86_64-latest.err create mode 100644 tests/qemuxml2argvdata/firmware-manual-efi-nvram-stateless.xml create mode 100644 tests/qemuxml2argvdata/firmware-manual-efi-nvram-template-stateless.x86_64-latest.err create mode 100644 tests/qemuxml2argvdata/firmware-manual-efi-nvram-template-stateless.xml create mode 100644 tests/qemuxml2xmloutdata/firmware-auto-bios-stateless.x86_64-latest.xml create mode 100644 tests/qemuxml2xmloutdata/firmware-manual-bios-stateless.xml create mode 100644 tests/qemuxml2xmloutdata/firmware-manual-bios.xml
diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst index 3ea094e64c..4199abfd1a 100644 --- a/docs/formatdomain.rst +++ b/docs/formatdomain.rst @@ -242,7 +242,11 @@ harddisk, cdrom, network) determining where to obtain/find the boot image. firmwares may implement the Secure boot feature. Attribute ``secure`` can be used to tell the hypervisor that the firmware is capable of Secure Boot feature. It cannot be used to enable or disable the feature itself in the firmware. - :since:`Since 2.1.0` + :since:`Since 2.1.0`. If the loader is marked as read-only, then with UEFI it + is assumed that there will be a writable NVRAM available. In some cases, + however, it may be desirable for the loader to run without any NVRAM, discarding + any config changes on shutdown. The ``stateless`` flag can be used to control + this behaviour, when set to ``no`` NVRAM will never be created.
The ``stateless` flag (:since:since 8.6.0) can be used ... Or something among those lines, to make it obvious when the attribute was added.
``nvram`` Some UEFI firmwares may want to use a non-volatile memory to store some variables. In the host, this is represented as a file and the absolute path
Michal