Re: [Qemu-devel] [PATCH 2/4] hw/virtio: Factorize virtio-mmio headers

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Jun 28, 2019 at 10:50:47PM +0200, Sergio Lopez wrote:
> 
> Michael S. Tsirkin <mst@redhat.com> writes:
> 
> > On Fri, Jun 28, 2019 at 01:53:47PM +0200, Sergio Lopez wrote:
> >> Put QOM and main struct definition in a separate header file, so it
> >> can be accesed from other components.
> >> 
> >> This is needed for the microvm machine type implementation.
> >> 
> >> Signed-off-by: Sergio Lopez <slp@redhat.com>
> >
> > If you are going to productise virtio-mmio, then 1.0 support is a must.
> > I am not sure we want a new machine with 0.X mmio devices.
> > Especially considering that virtio-mmio does not have support for
> > transitional devices.
> 
> What are the practical implications of that?

On the plus side, this means we don't need to maintain a bunch of hacks
for old guests with quirky drivers.

On the minus side, this requires Linux guests 3.19 and up.




> >> ---
> >>  hw/virtio/virtio-mmio.c | 35 +-----------------------
> >>  hw/virtio/virtio-mmio.h | 60 +++++++++++++++++++++++++++++++++++++++++
> >>  2 files changed, 61 insertions(+), 34 deletions(-)
> >>  create mode 100644 hw/virtio/virtio-mmio.h
> >> 
> >> diff --git a/hw/virtio/virtio-mmio.c b/hw/virtio/virtio-mmio.c
> >> index 97b7f35496..87c7fe4d8d 100644
> >> --- a/hw/virtio/virtio-mmio.c
> >> +++ b/hw/virtio/virtio-mmio.c
> >> @@ -26,44 +26,11 @@
> >>  #include "qemu/host-utils.h"
> >>  #include "qemu/module.h"
> >>  #include "sysemu/kvm.h"
> >> -#include "hw/virtio/virtio-bus.h"
> >> +#include "virtio-mmio.h"
> >>  #include "qemu/error-report.h"
> >>  #include "qemu/log.h"
> >>  #include "trace.h"
> >>  
> >> -/* QOM macros */
> >> -/* virtio-mmio-bus */
> >> -#define TYPE_VIRTIO_MMIO_BUS "virtio-mmio-bus"
> >> -#define VIRTIO_MMIO_BUS(obj) \
> >> -        OBJECT_CHECK(VirtioBusState, (obj), TYPE_VIRTIO_MMIO_BUS)
> >> -#define VIRTIO_MMIO_BUS_GET_CLASS(obj) \
> >> -        OBJECT_GET_CLASS(VirtioBusClass, (obj), TYPE_VIRTIO_MMIO_BUS)
> >> -#define VIRTIO_MMIO_BUS_CLASS(klass) \
> >> -        OBJECT_CLASS_CHECK(VirtioBusClass, (klass), TYPE_VIRTIO_MMIO_BUS)
> >> -
> >> -/* virtio-mmio */
> >> -#define TYPE_VIRTIO_MMIO "virtio-mmio"
> >> -#define VIRTIO_MMIO(obj) \
> >> -        OBJECT_CHECK(VirtIOMMIOProxy, (obj), TYPE_VIRTIO_MMIO)
> >> -
> >> -#define VIRT_MAGIC 0x74726976 /* 'virt' */
> >> -#define VIRT_VERSION 1
> >> -#define VIRT_VENDOR 0x554D4551 /* 'QEMU' */
> >> -
> >> -typedef struct {
> >> -    /* Generic */
> >> -    SysBusDevice parent_obj;
> >> -    MemoryRegion iomem;
> >> -    qemu_irq irq;
> >> -    /* Guest accessible state needing migration and reset */
> >> -    uint32_t host_features_sel;
> >> -    uint32_t guest_features_sel;
> >> -    uint32_t guest_page_shift;
> >> -    /* virtio-bus */
> >> -    VirtioBusState bus;
> >> -    bool format_transport_address;
> >> -} VirtIOMMIOProxy;
> >> -
> >>  static bool virtio_mmio_ioeventfd_enabled(DeviceState *d)
> >>  {
> >>      return kvm_eventfds_enabled();
> >> diff --git a/hw/virtio/virtio-mmio.h b/hw/virtio/virtio-mmio.h
> >> new file mode 100644
> >> index 0000000000..2f3973f8c7
> >> --- /dev/null
> >> +++ b/hw/virtio/virtio-mmio.h
> >> @@ -0,0 +1,60 @@
> >> +/*
> >> + * Virtio MMIO bindings
> >> + *
> >> + * Copyright (c) 2011 Linaro Limited
> >> + *
> >> + * Author:
> >> + *  Peter Maydell <peter.maydell@linaro.org>
> >> + *
> >> + * This program is free software; you can redistribute it and/or modify
> >> + * it under the terms of the GNU General Public License; either version 2
> >> + * of the License, or (at your option) any later version.
> >> + *
> >> + * This program is distributed in the hope that it will be useful,
> >> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> >> + * GNU General Public License for more details.
> >> + *
> >> + * You should have received a copy of the GNU General Public License along
> >> + * with this program; if not, see <http://www.gnu.org/licenses/>.
> >> + */
> >> +
> >> +#ifndef QEMU_VIRTIO_MMIO_H
> >> +#define QEMU_VIRTIO_MMIO_H
> >> +
> >> +#include "hw/virtio/virtio-bus.h"
> >> +
> >> +/* QOM macros */
> >> +/* virtio-mmio-bus */
> >> +#define TYPE_VIRTIO_MMIO_BUS "virtio-mmio-bus"
> >> +#define VIRTIO_MMIO_BUS(obj) \
> >> +        OBJECT_CHECK(VirtioBusState, (obj), TYPE_VIRTIO_MMIO_BUS)
> >> +#define VIRTIO_MMIO_BUS_GET_CLASS(obj) \
> >> +        OBJECT_GET_CLASS(VirtioBusClass, (obj), TYPE_VIRTIO_MMIO_BUS)
> >> +#define VIRTIO_MMIO_BUS_CLASS(klass) \
> >> +        OBJECT_CLASS_CHECK(VirtioBusClass, (klass), TYPE_VIRTIO_MMIO_BUS)
> >> +
> >> +/* virtio-mmio */
> >> +#define TYPE_VIRTIO_MMIO "virtio-mmio"
> >> +#define VIRTIO_MMIO(obj) \
> >> +        OBJECT_CHECK(VirtIOMMIOProxy, (obj), TYPE_VIRTIO_MMIO)
> >> +
> >> +#define VIRT_MAGIC 0x74726976 /* 'virt' */
> >> +#define VIRT_VERSION 1
> >> +#define VIRT_VENDOR 0x554D4551 /* 'QEMU' */
> >> +
> >> +typedef struct {
> >> +    /* Generic */
> >> +    SysBusDevice parent_obj;
> >> +    MemoryRegion iomem;
> >> +    qemu_irq irq;
> >> +    /* Guest accessible state needing migration and reset */
> >> +    uint32_t host_features_sel;
> >> +    uint32_t guest_features_sel;
> >> +    uint32_t guest_page_shift;
> >> +    /* virtio-bus */
> >> +    VirtioBusState bus;
> >> +    bool format_transport_address;
> >> +} VirtIOMMIOProxy;
> >> +
> >> +#endif
> >> -- 
> >> 2.21.0
>