Re: [PATCH 1/1] OvmfPkg: drop redundant VendorID check in VirtioMmioDeviceLib

["Leif Lindholm" <leif@nuviainc.com>]

On Mon, Sep 14, 2020 at 17:35:13 +0200, Laszlo Ersek wrote:
> Hi Leif,
> 
> On 09/12/20 18:40, Leif Lindholm wrote:
> > There is a DEBUG warning printout in VirtioMmioDeviceLib if the current
> > device's VendorID does not match the traditional 16-bit Red Hat PCIe
> > vendor ID used with virtio-pci. The virtio-mmio vendor ID is 32-bit and
> > has no connection to the PCIe registry.
> > 
> > Most specifically, this causes a bunch of noise when booting an AArch64
> > QEMU platform, since QEMU's virtio-mmio implementation used 'QEMU' as
> > the vendor ID:
> > VirtioMmioInit: Warning:
> >   The VendorId (0x554D4551) does not match the VirtIo VendorId (0x1AF4).
> 
> Good catch -- in QEMU, this has been the case since initial virtio-mmio
> commit 4b52530be987 ("virtio: Implement MMIO based virtio transport",
> 2013-07-19); and indeed neither the virtio-0.9.5 spec, nor the "Legacy
> MMIO" part of the 1.0 spec, require this vendor ID to be 0x1AF4.
> 
> Reviewed-by: Laszlo Ersek <lersek@redhat.com>

Thanks!
Merged as 5648836987ca / #935.

> Thanks
> Laszlo
> 
> > 
> > Drop the warning message.
> > 
> > Cc: Jordan Justen <jordan.l.justen@intel.com>
> > Cc: Laszlo Ersek <lersek@redhat.com>
> > Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
> > Signed-off-by: Leif Lindholm <leif@nuviainc.com>
> > ---
> >  .../VirtioMmioDeviceLib/VirtioMmioDevice.c        | 15 ---------------
> >  1 file changed, 15 deletions(-)
> > 
> > diff --git a/OvmfPkg/Library/VirtioMmioDeviceLib/VirtioMmioDevice.c b/OvmfPkg/Library/VirtioMmioDeviceLib/VirtioMmioDevice.c
> > index 2f20272c1445..6dbbba008c75 100644
> > --- a/OvmfPkg/Library/VirtioMmioDeviceLib/VirtioMmioDevice.c
> > +++ b/OvmfPkg/Library/VirtioMmioDeviceLib/VirtioMmioDevice.c
> > @@ -58,7 +58,6 @@ VirtioMmioInit (
> >    )
> >  {
> >    UINT32     MagicValue;
> > -  UINT32     VendorId;
> >    UINT32     Version;
> >  
> >    //
> > @@ -84,20 +83,6 @@ VirtioMmioInit (
> >      return EFI_UNSUPPORTED;
> >    }
> >  
> > -  //
> > -  // Double-check MMIO-specific values
> > -  //
> > -  VendorId = VIRTIO_CFG_READ (Device, VIRTIO_MMIO_OFFSET_VENDOR_ID);
> > -  if (VendorId != VIRTIO_VENDOR_ID) {
> > -    //
> > -    // The ARM Base and Foundation Models do not report a valid VirtIo VendorId.
> > -    // They return a value of 0x0 for the VendorId.
> > -    //
> > -    DEBUG((DEBUG_WARN, "VirtioMmioInit: Warning: The VendorId (0x%X) does not "
> > -                       "match the VirtIo VendorId (0x%X).\n",
> > -                       VendorId, VIRTIO_VENDOR_ID));
> > -  }
> > -
> >    return EFI_SUCCESS;
> >  }
> >  
> > 
>