Michal Prívozník wrote:
> On 1/12/26 20:17, Roman Bogorodskiy wrote:
> > The "virt" board in QEMU has a "virtualization" option
> > that is documented like this:
> >
> > virtualization
> > Set ``on``/``off`` to enable/disable emulating a guest CPU which
> > implements the
> > Arm Virtualization Extensions. The default is ``off``.
> >
> > (from system/arm/virt.rst)
> >
> > According to the documentation, the "virtualiaztion" option
> > is related to the "gic-version" option. Specifically, gic version=4
> > requires virtualization to be enabled. And gic version=max will use
> > version=4 when virtualization is enabled, and 3 when not.
> > Libvirt does not currently model neither gic version "3" nor "max"
>
> yes we do model GICv3 actually, but not 4.
Sorry, that was a typo, it should have been 'version "4" nor "max"'.
> ``gic``
> Enable for architectures using a General Interrupt Controller instead of
> APIC
> in order to handle interrupts. For example, the 'aarch64' architecture uses
> ``gic`` instead of ``apic``. The optional attribute ``version`` specifies
> the
> GIC version; however, it may not be supported by all hypervisors. Accepted
> values are ``2``, ``3`` and ``host``. :since:`Since 1.2.16`
>
> And there's this one funny comment in hw/arm/virt.c:
>
> static VirtGICType finalize_gic_version_do(const char *accel_name,
> VirtGICType gic_version,
> int gics_supported,
> unsigned int max_cpus)
> {
> /* Convert host/max/nosel to GIC version number */
> switch (gic_version) {
> case VIRT_GIC_VERSION_HOST:
> if (!kvm_enabled()) {
> error_report("gic-version=host requires KVM");
> exit(1);
> }
>
> /* For KVM, gic-version=host means gic-version=max */
> return finalize_gic_version_do(accel_name, VIRT_GIC_VERSION_MAX,
> gics_supported, max_cpus);
>
> > though.
> >
> > It is also documented for the "vexpress-a(9|15)" boards, where it is
> > also disabled by default:
> >
> > - QEMU defaults to providing a CPU which does not provide either
> > TrustZone or the Virtualization Extensions: if you want these you
> > must enable them with ``-machine secure=on`` and ``-machine
> > virtualization=on``
> >
> > (system/arm/vexpress.rst).
> >
> > On the command line it looks like:
> >
> > qemu-system-aarch64 -machine type=virt,virtualization=on ..
> >
> > Model it using the "virtualization" element in the "features" section:
> >
> > <features>
> > <virtualization/>
> > </features>
> >
> > Signed-off-by: Roman Bogorodskiy <[email protected]>
> > ---
> > docs/formatdomain.rst | 4 ++
> > src/conf/domain_conf.c | 4 ++
> > src/conf/domain_conf.h | 1 +
> > src/conf/schemas/domaincommon.rng | 5 +++
> > src/qemu/qemu_command.c | 9 ++++
> > src/qemu/qemu_validate.c | 1 +
> > ...64-virt-virtualization.aarch64-latest.args | 38 ++++++++++++++++
> > ...h64-virt-virtualization.aarch64-latest.xml | 45 +++++++++++++++++++
> > .../aarch64-virt-virtualization.xml | 25 +++++++++++
> > tests/qemuxmlconftest.c | 2 +
> > 10 files changed, 134 insertions(+)
> > create mode 100644
> > tests/qemuxmlconfdata/aarch64-virt-virtualization.aarch64-latest.args
> > create mode 100644
> > tests/qemuxmlconfdata/aarch64-virt-virtualization.aarch64-latest.xml
> > create mode 100644 tests/qemuxmlconfdata/aarch64-virt-virtualization.xml
>
> Reviewed-by: Michal Privoznik <[email protected]>
>
> Michal
>
