Re: [PATCH v2 01/22] block: add eMMC block device type

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Sai Pavan Boddu (saipava@xilinx.com) wrote:
> Hi Philippe,
> 
> > -----Original Message-----
> > From: Philippe Mathieu-Daudé <philmd@redhat.com>
> > Sent: Monday, February 22, 2021 6:54 PM
> > To: Dr. David Alan Gilbert <dgilbert@redhat.com>; Markus Armbruster
> > <armbru@redhat.com>
> > Cc: Sai Pavan Boddu <saipava@xilinx.com>; Kevin Wolf <kwolf@redhat.com>;
> > Max Reitz <mreitz@redhat.com>; Vladimir Sementsov-Ogievskiy
> > <vsementsov@virtuozzo.com>; Eric Blake <eblake@redhat.com>; Joel Stanley
> > <joel@jms.id.au>; Cédric Le Goater <clg@kaod.org>; Vincent Palatin
> > <vpalatin@chromium.org>; Thomas Huth <thuth@redhat.com>; Stefan
> > Hajnoczi <stefanha@redhat.com>; Peter Maydell <peter.maydell@linaro.org>;
> > Alistair Francis <alistair.francis@wdc.com>; Edgar Iglesias <edgari@xilinx.com>;
> > Luc Michel <luc.michel@greensocs.com>; Paolo Bonzini
> > <pbonzini@redhat.com>; Sai Pavan Boddu <saipava@xilinx.com>; qemu-
> > devel@nongnu.org; qemu-block@nongnu.org
> > Subject: Re: [PATCH v2 01/22] block: add eMMC block device type
> > 
> > On 2/22/21 2:16 PM, Dr. David Alan Gilbert wrote:
> > > * Markus Armbruster (armbru@redhat.com) wrote:
> > >> Philippe Mathieu-Daudé <philmd@redhat.com> writes:
> > >>
> > >>> On 2/22/21 9:20 AM, Sai Pavan Boddu wrote:
> > >>>> From: Vincent Palatin <vpalatin@chromium.org>
> > >>>>
> > >>>> Add new block device type.
> > >>>>
> > >>>> Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
> > >>>> [SPB: Rebased over 5.1 version]
> > >>>> Signed-off-by: Sai Pavan Boddu <sai.pavan.boddu@xilinx.com>
> > >>>> Signed-off-by: Joel Stanley <joel@jms.id.au>
> > >>>> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> > >>>> Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
> > >>>> ---
> > >>>>  include/sysemu/blockdev.h | 1 +
> > >>>>  blockdev.c                | 1 +
> > >>>>  2 files changed, 2 insertions(+)
> > >>>>
> > >>>> diff --git a/include/sysemu/blockdev.h b/include/sysemu/blockdev.h
> > >>>> index 3b5fcda..eefae9f 100644
> > >>>> --- a/include/sysemu/blockdev.h
> > >>>> +++ b/include/sysemu/blockdev.h
> > >>>> @@ -24,6 +24,7 @@ typedef enum {
> > >>>>       */
> > >>>>      IF_NONE = 0,
> > >>>>      IF_IDE, IF_SCSI, IF_FLOPPY, IF_PFLASH, IF_MTD, IF_SD,
> > >>>> IF_VIRTIO, IF_XEN,
> > >>>> +    IF_EMMC,
> > >>>>      IF_COUNT
> > >>>>  } BlockInterfaceType;
> > >>>>
> > >>>> diff --git a/blockdev.c b/blockdev.c index cd438e6..390d43c 100644
> > >>>> --- a/blockdev.c
> > >>>> +++ b/blockdev.c
> > >>>> @@ -83,6 +83,7 @@ static const char *const if_name[IF_COUNT] = {
> > >>>>      [IF_SD] = "sd",
> > >>>>      [IF_VIRTIO] = "virtio",
> > >>>>      [IF_XEN] = "xen",
> > >>>> +    [IF_EMMC] = "emmc",
> > >>>>  };
> > >>>
> > >>> We don't need to introduce support for the legacy -drive magic.
> > >>>
> > >>> -device should be enough for this device, right?
> > >>
> > >> External interface extensions need rationale: why do we want / need it?
> > >> The commit message neglects to provide one.
> > >>
> > >> Even more so when the interface in question is in a state like -drive
> > >> is.
> > >
> > > I wouldn't be too nasty about -drive;  for me I still find it the
> > > easiest way to start a VM.
> > 
> > But eMMC isn't a bus where you can plug drives, it is soldered on-board and is
> > mmio mapped to a fixed address. I don't see the point of having a drive
> > interface for it...
> [Sai Pavan Boddu] Yeah, this makes sense but having a drive would be a simple implementation without disturbing much in the sd card emulation code. And its just easy to use, just as how sd cards are inserted.
> 
> I need to see, how easy it would be with -device.


Lets see what your command line looks like for starting it with emmc.

Dave

> Thanks,
> Sai Pavan
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK