Re: [PATCH v3] hw/smbios: support for type 41 (onboard devices extended information)

From: Igor Mammedov <imammedo@redhat.com>
To: Andrew Jones <drjones@redhat.com>
Cc: "Peter Maydell" <peter.maydell@linaro.org>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	"Daniel P . Berrangé" <berrange@redhat.com>,
	qemu-devel@nongnu.org, "Vincent Bernat" <vincent@bernat.ch>
Subject: Re: [PATCH v3] hw/smbios: support for type 41 (onboard devices extended information)
Date: Tue, 6 Apr 2021 20:36:13 +0200	[thread overview]
Message-ID: <20210406203613.01cdf294@redhat.com> (raw)
In-Reply-To: <20210406074250.hsmm5yrzhfxdwjs4@kamzik.brq.redhat.com>

On Tue, 6 Apr 2021 09:42:50 +0200
Andrew Jones <drjones@redhat.com> wrote:

> On Thu, Apr 01, 2021 at 11:32:25PM +0200, Igor Mammedov wrote:
> > On Thu, 01 Apr 2021 23:07:06 +0200
> > Vincent Bernat <vincent@bernat.ch> wrote:
> >   
> > >  ❦  1 avril 2021 22:58 +02, Igor Mammedov:
> > >   
> > > >> This can be invoked with:
> > > >> 
> > > >>     $QEMU -netdev user,id=internet
> > > >>           -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \
> > > >>           -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev    
> > > >
> > > > an ACPI alternative was merged recently (current master).
> > > > assigning 'designation=' wasn't implemented there, but important part
> > > > of giving users control over PCI devices 'eno' index is implemented.
> > > >
> > > > When I looked into the issue, smbios way was a bit over-kill for the task
> > > > and didn't really work if hotplug were used.
> > > >
> > > > See, for example how to use new feature:
> > > >  https://www.mail-archive.com/qemu-devel@nongnu.org/msg794164.html    
> > > 
> > > It seems simpler this way. I don't think my patch is needed then.  
> > 
> > SMBIOS ways is fine for static configs where no hot-plug is involved.
> > Also potentially SMBIOS way may be used by arm/virt board,
> > since acpi-index shares a lot with ACPI PCI hotplug infrastructure
> > and we haven't ported that to arm/virt impl. yet.
> > 
> > It also won't work for Q35 at the moment, but Julia is working
> > on adding support for ACPI PCI hotplug to it, and once it arrives
> > acpi-index will become available there.
> > 
> > Perhaps we should also add support for ACPI PCI hotplug to virt/arm,
> > along with Q35.
> >  
> 
> What's required of the guest kernel for ACPI PCI hotplug? If there are
> arch-specific aspects to that, then do we know if Linux for AArch64
> has the support?

I could only guess, it could be just a matter turning on HOTPLUG_PCI_ACPI
in Kconfig.

> 
> Thanks,
> drew