On Thu, Mar 14, 2019 at 07:45:56PM +0000, Igor Druzhinin wrote: > On 14/03/2019 17:41, Anthony PERARD wrote: > > Hi, > > > > On Wed, Mar 06, 2019 at 12:40:54PM +0000, Igor Druzhinin wrote: > >> This aperture doesn't exist in OVMF and trying to use it causes > > > > I'm trying to understand what you mean by writing "doesn't exist in > > OVMF". Are prefetchable BAR not handled by ScanForRootBridges() ? > > Or is it the emulation of the config space that isn't correct? > > Maybe QEMU should lies about a BAR been prefetchable? > > The problem here is: hvmloader places BARs initially disregarding > prefetchable bit in an arbitrary order because essentially there is only > 1 aperture for the host bridge in emulated system under Xen (and KVM as > well). In PcatPciRootBridgeParseBars() we construct apertures for high > level OVMF code by reading the BAR placement information after > hvmloader. It often appears that there are prefetchable and > non-prefetchable BARs coexist with each other and make prefetchable and > non-prefetchable apertures overlap. This eventually triggers an > assertion in high level OVMF code because that shouldn't happen.
Thanks for the explanation. Could you add it to the patch description? > OVMF for KVM is not using prefetchable BAR at all - see > PciHostBridgeGetRootBridges() in which it passes mNonExistAperture dummy > object to high level code. I think it's wrong to construct a > prefetchable aperture for Xen and this code should be removed as it's > done for QEMU-KVM. Do you think this patch needs to do that? It would be nice to remove the code that isn't useful so feel free to do it and/or keep the current patch with the description updated. Thanks, -- Anthony PERARD _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
