Re: [PATCH v4] hw/smbios: support for type 41 (onboard devices extended information)

From: "Michael S. Tsirkin" <mst@redhat.com>
To: Vincent Bernat <vincent@bernat.ch>
Cc: "Igor Mammedov" <imammedo@redhat.com>,
	"Daniel P . Berrangé" <berrange@redhat.com>,
	qemu-devel@nongnu.org
Subject: Re: [PATCH v4] hw/smbios: support for type 41 (onboard devices extended information)
Date: Mon, 3 May 2021 15:42:16 -0400	[thread overview]
Message-ID: <20210503154024-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <m3sg338vcd.fsf@bernat.ch>

On Mon, May 03, 2021 at 09:34:42PM +0200, Vincent Bernat wrote:
>  ❦  3 mai 2021 17:05 +02, Igor Mammedov:
> 
> >> +            /*
> >> +             * We only handle the case were the device is attached to
> >> +             * the PCI root bus. The general case is more complex as
> >> +             * bridges are enumerated later and the table would need
> >> +             * to be updated at this moment.
> >> +             */
> >> +            if (!pci_bus_is_root(pci_get_bus(pdev))) {
> >> +                error_setg(errp,
> >> +                           "Cannot create type 41 entry for PCI device %s: "
> >> +                           "not attached to the root bus",
> >> +                           t41->pcidev);
> >> +                return;
> >> +            }
> > Is this limitation really necessary?
> >
> > As far as I see caller of this smbios_get_tables(), is called at machine_done time
> > when all devices (including bridges) present on CLI are created.
> 
> I wasn't sure how to get the segment group number in this case. It seems
> this is not exposed directly. There is a root_bus_path method returning
> a string that would need to be parsed to extract the segment group
> number. Looking a bit, it seems to be always 0.
> -- 
> Don't stop with your first draft.
>             - The Elements of Programming Style (Kernighan & Plauger)

and not just that. the code comments explains the motivation even
with a single segment.

-- 
MST