On Sat, Jun 09, 2018 at 12:30:14PM +0200, Ard Biesheuvel wrote: > > > > On 9 Jun 2018, at 12:06, Christoffer Dall <christoffer.dall@xxxxxxx> wrote: > > > >> On Fri, Jun 01, 2018 at 05:06:28PM +0200, Ard Biesheuvel wrote: > >> When booting a 64 KB pages kernel on a ACPI GICv3 system that > >> implements support for v2 emulation, the following warning is > >> produced > >> > >> GICV size 0x2000 not a multiple of page size 0x10000 > >> > >> and support for v2 emulation is disabled, preventing GICv2 VMs > >> from being able to run on such hosts. > >> > >> The reason is that vgic_v3_probe() performs a sanity check on the > >> size of the window (it should be a multiple of the page size), > >> while the ACPI MADT parsing code hardcodes the size of the window > >> to 8 KB. This makes sense, considering that ACPI does not bother > >> to describe the size in the first place, under the assumption that > >> platforms implementing ACPI will follow the architecture and not > >> put anything else in the same 64 KB window. > > > > Does the architecture actually say that anywhere? > > > >> > >> So let's just drop the sanity check altogether, and assume that > >> the window is at least 64 KB in size. > > > > This could obviously be dangerous if broken systems actually exist. > > Marc may know more about that than me. An alternative would be to > > modify the ACPI code to assume max(8 KB, page size) instead, and/or a > > command line parameter to override this check. > > > > That said, I'm not directly opposed to this patch, but I'll let Marc > > have a look as well. > > > > This approach was actually Marc’s idea, and he already applied the patch to the queue branch afaik. > Hmmm, ok. -Christoffer _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
