[libvirt] [PATCH 3/3] qemu: use qemu-xhci USB controller by default for ppc64 and aarch64

Pavel Hrdina phrdina at redhat.com
Thu Apr 27 14:19:46 UTC 2017


On Thu, Apr 27, 2017 at 04:13:43PM +0200, Andrea Bolognani wrote:
> On Thu, 2017-04-27 at 10:24 +0200, Pavel Hrdina wrote:
> > > You're technically correct[1]. However, piix3-uhci is
> > > another piece of Intel-derived hardware so in practice
> > > qemu-system-aarch64 is very unlikely to have it compiled
> > > in and most users will end up getting the error instead.
>> > Isn't the nec-xhci also Intel hardware, so the same would apply to that
> > controller as well.
> 
> Not quite:
> 
>   Intel Corporation 82371SB PIIX3 USB [Natoma/Triton II] [8086:7020]
>   NEC Corporation uPD720200 USB 3.0 Host Controller [1033:0194]
> 
> The vendor for piix3-uhci is Intel Corporation, the vendor
> for nec-xhci is NEC Corporation.
> 
> I guess both are unlikely to show up in actual aarch64
> hardware, but the former is clearly x86-specific while the
> latter is somewhat more architecture-agnostic.
> 
> > Moreover, this probably happens only for downstream
> > builds of QEMU (most likely only RHEL/CentOS) as there is no configure
> > option for that.  QEMU has some default configs for different architectures
> > but in upstream QEMU the set of UHCI usb controllers is enabled by default
> > for aarch64.
> 
> The upstream QEMU configuration takes the kitchen sink
> approach, eg. qemu-system-ppc64 will include allwinner-ahci
> and other devices that clearly have no place in a ppc64
> guest, so I don't think we should take that as an indication
> that piix-uhci is something anyone will want to reasonably
> use on aarch64 :)

My point was that we should not make any decisions based on downstream
configurations :).

Like I said, I'll send v2 with nec-xhci enabled for aarch64.

Pavel

> 
> -- 
> Andrea Bolognani / Red Hat / Virtualization
> 
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> libvir-list at redhat.com
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