On 03/21/2012 10:10 AM, Michael S. Tsirkin wrote:
On Wed, Mar 21, 2012 at 09:42:41AM -0500, Anthony Liguori wrote:
On 03/21/2012 08:08 AM, Michael S. Tsirkin wrote:
On Wed, Mar 21, 2012 at 11:26:15AM +0000, Stefan Hajnoczi wrote:
On Tue, Mar 20, 2012 at 09:19:47PM +1100, David Gibson wrote:
Looking at hw/pc_piix.c there are QEMUMachine types for each QEMU
release. Legacy machine types (e.g. pc_machine_v0_14) have a
.compat_props array that can override qdev properties.
Perhaps Michael Tsirkin or someone else can comment on how to wire up
hw/virtio-pci.c so that the class code can be overridden.
Stefan
afaik we already let users over-write it for some other pci devices,
look there for examples.
From hw/pc_piix.c:
.name = "pc-0.10",
.desc = "Standard PC, qemu 0.10",
.init = pc_init_pci_no_kvmclock,
.max_cpus = 255,
.compat_props = (GlobalProperty[]) {
{
.driver = "virtio-blk-pci",
.property = "class",
.value = stringify(PCI_CLASS_STORAGE_OTHER),
},{
And from the earlier part of the thread, yes, it's imperative that
we do not change anything in the PCI configuration space for older
pc versions regardless of whether it may or may not work.
Certain guests (like Windows) use a complex fingerprinting algorithm
to determine when hardware changes. It can be hard to detect in
simple testing because it's based on a threshold.
Regards,
Anthony Liguori
Which reminds me - qemu sticks the release version in
guest visible places like CPU version.
This is wrong and causes windows guests to print messages
about driver updates when you switch.
We should find all these places and stop doing this.
We could probably get away with doing a query/replace of QEMU_VERSION with
qemu_get_version(), make version a static variable that defaults to
QEMU_VERSION, and then provide a way for machines to override it.
Then pc-0.10 could report a version of 0.10.
Regards,
Anthony Liguori
