On 03/21/19 01:53, Laszlo Ersek wrote:
> Hi Paolo,
>
> (+libvir-list)
>
> I'd like to report a regression introduced by this patch set:
>
> On 03/07/19 21:58, Paolo Bonzini wrote:
>> The following changes since commit
>> 6cb4f6db4f4367faa33da85b15f75bbbd2bed2a6:
>>
>> Merge remote-tracking branch
>> 'remotes/cleber/tags/python-next-pull-request' into staging
>> (2019-03-07 16:16:02 +0000)
>>
>> are available in the Git repository at:
>>
>> git://github.com/bonzini/qemu.git tags/for-upstream-kconfig
>>
>> for you to fetch changes up to
>> 576c3f2f16e7392e28cc9fe10d9a920d67d3645b:
>>
>> kconfig: add documentation (2019-03-07 21:54:22 +0100)
>>
>> ----------------------------------------------------------------
>> Initial Kconfig work, excluding ARM and MIPS
>>
>> ----------------------------------------------------------------
>
In brief, the regression is that the aarch64 system emulator now lists
the "virtio-vga" device for the "virt" machine type:
$ qemu-system-aarch64 -M virt -device \? | grep virtio-vga
name "virtio-vga", bus PCI
Here's where I think the issue was introduced:
(1) In commit 82f5181777eb ("kconfig: introduce kconfig files",
2019-03-07), VIRTIO_VGA was introduced simply as a bool (with no other
clauses) in "hw/display/Kconfig".
(2) In commit 7c28b925b7e1 ("build: convert pci.mak to Kconfig",
2019-03-07), VIRTIO_VGA received the following clauses:
default y if PCI_DEVICES
depends on VIRTIO_PCI
select VGA
This is too lax, because it permits virtio-vga for aarch64, while that
shouldn't happen (and it doesn't matches the previous state of the tree).
Similar case I noticed in another thread. The Virt machine uses a chipset that provides PCI. Does this machine expose PCI slots? If yes, this config is correct, the machine can get any PCI daughter card. Else we shouldn't use PCI_DEVICES that way.
Why Virt machine now default to virtio-vga?
(3) In commit b42075bb7767 ("virtio: express virtio dependencies with
Kconfig", 2019-03-07), the determination of virtio-vga was switched to
the Kconfig system. Importantly, in this patch, the line
CONFIG_VIRTIO_VGA=y
was removed *only* from the following file:
default-configs/i386-softmmu.mak
(4) Both of the remaining instances of
CONFIG_VIRTIO_VGA=y
were then removed in commit 9483cf27dd36 ("hppa-softmmu.mak: express
dependencies with Kconfig", 2019-03-07) and commit 87f9108bad0c ("ppc64:
Express dependencies of 'pseries' and 'powernv' machines with kconfig",
2019-03-07), from files
default-configs/hppa-softmmu.mak
default-configs/ppc64-softmmu.mak
respectively.
Therefore I think commit 7c28b925b7e1 has the bug. The VIRTIO_VGA
restriction
depends on VIRTIO_PCI
should now be replaced with
depends on VIRTIO_PCI && (PC || DINO || PSERIES)
Thanks
Laszlo