On 25.07.2019 15:34, Roger Pau Monné wrote: > On Thu, Jul 25, 2019 at 12:47:01PM +0000, Jan Beulich wrote: >> On 24.07.2019 11:43, Jan Beulich wrote: >>> On 23.07.2019 18:45, Andrew Cooper wrote: >>>> On 23/07/2019 17:09, Jan Beulich wrote: >>>>> On 23.07.2019 17:48, Roger Pau Monne wrote: >>>>>> Current code only prevents mapping the io-apic page into the guest >>>>>> physical memory map. Expand the range to be 0xFECx_xxxx as described >>>>>> in the Intel 3 Series Chipset Datasheet section 3.3.1 "APIC >>>>>> Configuration Space (FEC0_0000h–FECF_FFFFh)". >>>>>> >>>>>> AMD also lists this address range in the AMD SR5690 Databook, section >>>>>> 2.4.2 "Non-SB IOAPIC Support". >>>>> But that's chipset specific. I don't think we can blindly assume >>>>> this range. >>>> >>>> The IO-APIC has always lived in that region since its introduction, and >>>> the location isn't even configurable on newer chipsets (If I've read the >>>> SAD routing rules in Skylake correctly. All that can be configured is >>>> multiple IO-APICs being mapped adjacent to each other.) >>> >>> I'm pretty sure I've seen IO-APICs outside that range. >> >> From my AMD Fam15 system: >> >> <7>ACPI: Local APIC address 0xfee00000 >> <6>IOAPIC[0]: apic_id 0, version 33, address 0xfec00000, GSI 0-23 >> <6>IOAPIC[1]: apic_id 1, version 33, address 0xc8000000, GSI 24-55 > > Hm, I guess the only option is to then blacklist the proposed range > plus any of the pages of the io-apics on the system. I can send a new > version without dropping the current io-apic blacklisting, but then > I'm not sure there's much value in adding the FEC0_0000h–FECF_FFFFh > range.
Neither am I, hence my initial reaction. I'm surprised you don't see much value in there anymore - after all it's quite a bit larger an area that gets guarded against getting populated, as we're unlikely to see many systems with this space fully (or even just mostly) used by many, many IO-APICs. As said, I'd be fine acking the patch with the loop left in place, and with the description refined. Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
