On Wed, 15 Apr 2015 12:38:57 +0200 "Michael S. Tsirkin" <m...@redhat.com> wrote:
> On Tue, Mar 03, 2015 at 05:18:12PM +0100, Igor Mammedov wrote: > > Changes since v13: > > * fix comment style to /*... */ in testcase > > * make BAR TARGET_PAGE_SIZE as required by spec > > * make BAR prefetchable, spec also says that it shouldn't be > > marked as non cached > > * ACPI part > > * merge separate VGID device with PCI device description > > * mark device as not shown in UI, > > it hides "VM Generation ID" device from device manager > > and leaves only "PCI Standard RAM Controller" device there > > In an offline chat, Yan (Cc) mentioned that with windows guests, > PCI rebalancing can move BAR values around. > Yan, could you comment on-list please? > Is there a way to force this, for testing? > > ACPI spec mentions this: > If a platform uses a PCI BAR Target operation region, an ACPI OS will > not load a native device driver for the associated PCI function. For > example, if any of the BARs in a PCI function are associated with a PCI > BAR Target operation region, then the OS will assume that the PCI > function is to be entirely under the control of the ACPI BIOS. No driver > will be loaded. Thus, a PCI function can be used as a platform > controller for some task (hot-plug PCI, and so on) that the ACPI BIOS > performs. It seems that WS2012R2 doesn't honor this part of spec, it still tries to find matching driver and load it. > > This might also avoid driver prompt from windows? it isn't.