Re: [PATCH for-5.1 4/4] docs/system: Document the arm virt board

[Peter Maydell <peter.maydell@linaro.org>]

On Tue, 14 Jul 2020 at 15:58, Alex Bennée <alex.bennee@linaro.org> wrote:
>
>
> Peter Maydell <peter.maydell@linaro.org> writes:
>
> > Document the arm 'virt' board, which has been undocumented
> > for far too long given that it is the main recommended board
> > type for arm guests.
> >
> > Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> > ---
> >  docs/system/arm/virt.rst   | 157 +++++++++++++++++++++++++++++++++++++
> >  docs/system/target-arm.rst |   1 +
> >  MAINTAINERS                |   1 +
> >  3 files changed, 159 insertions(+)
> >  create mode 100644 docs/system/arm/virt.rst
> >
> > diff --git a/docs/system/arm/virt.rst b/docs/system/arm/virt.rst
> > new file mode 100644
> > index 00000000000..6a7823d8bca
> > --- /dev/null
> > +++ b/docs/system/arm/virt.rst
> > @@ -0,0 +1,157 @@
> > +'virt' generic virtual platform (``virt``)
> > +==========================================
> > +
> > +The `virt` board is a platform which does not correspond to any
> > +real hardware; it is designed for use in virtual machines.
> > +It is the recommended board type if you simply want to run
> > +a guest such as Linux and do not care about reproducing the
> > +idiosyncrasies and limitations of a particular bit of real-world
> > +hardware.
> > +
> > +This is a "versioned" board model, so as well as the ``virt`` machine
> > +type itself (which may have improvements, bugfixes and other minor
> > +changes between QEMU versions) a version is provided that guarantees
> > +to have the same behaviour as that of previous QEMU releases, so
> > +that VM migration will work between QEMU versions. For instance the
> > +``virt-5.0`` machine type will behave like the ``virt`` machine from
> > +the QEMU 5.0 release, and migration should work between ``virt-5.0``
> > +of the 5.0 release and ``virt-5.0`` of the 5.1 release. Migration
> > +is not guaranteed to work between different QEMU releases for
> > +the non-versioned ``virt`` machine type.
> > +
> > +Supported devices
> > +"""""""""""""""""
> > +
> > +The virt board supports:
> > +
> > +- Flash memory
> > +- One PL011 UART
> > +- An RTC
> > +- The fw_cfg device that allows a guest to obtain data from QEMU
> > +- A PL061 GPIO controller
> > +- An optional SMMUv3 IOMMU
> > +- hotpluggable DIMMs
> > +- hotpluggable NVDIMs
> > +- 32 virtio-mmio transport devices
>
> We seem to miss out we also support the virtio-pci transports here.

That's just a special case of "PCI", which I did indeed somehow forget.

 + PCI devices

thanks
-- PMM