Re: [edk2-devel] [PATCH 1/1] OvmfPkg/PlatformInitLib: pass through reservations from qemu

["Lendacky, Thomas" <thomas.lendacky@amd.com>]

On 1/16/23 11:09, Ard Biesheuvel wrote:
> On Thu, 12 Jan 2023 at 18:09, Tom Lendacky <thomas.lendacky@amd.com> wrote:
>>
>> On 12/6/22 23:32, Gerd Hoffmann via groups.io wrote:
>>> qemu uses the etc/e820 fw_cfg file not only for memory, but
>>> also for reservations.  Handle reservations by adding resource
>>> descriptor hobs for them.
>>>
>>> A typical qemu configuration has a small reservation between
>>> lapic and flash:
>>>
>>>     # sudo cat /proc/iomem
>>>     [ ... ]
>>>     fee00000-fee00fff : Local APIC
>>>     feffc000-feffffff : Reserved          <= HERE
>>>     ffc00000-ffffffff : Reserved
>>>     [ ... ]
>>>
>>> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
>>
>> On newer versions of Qemu, this patch causes a boot failure on my
>> AMD system with the following output:
>>
>> ...
>> PciHostBridgeUtilityInitRootBridge: populated root bus 0, with room for 255 subordinate bus(es)
>> RootBridge: PciRoot(0x0)
>>     Support/Attr: 70069 / 70069
>>       DmaAbove4G: No
>> NoExtConfSpace: No
>>        AllocAttr: 3 (CombineMemPMem Mem64Decode)
>>              Bus: 0 - FF Translation=0
>>               Io: 6000 - FFFF Translation=0
>>              Mem: C0000000 - FBFFFFFF Translation=0
>>       MemAbove4G: E000000000 - FFFFFFFFFF Translation=0
>>             PMem: FFFFFFFFFFFFFFFF - 0 Translation=0
>>      PMemAbove4G: FFFFFFFFFFFFFFFF - 0 Translation=0
>> PciHostBridgeDxe: IntersectMemoryDescriptor: desc [FD00000000, 10000000000) type 1 cap 8000000000026000 conflicts with aperture [E000000000, 10000000000) cap 1
>>
>> ASSERT_EFI_ERROR (Status = Invalid Parameter)
>> ASSERT [PciHostBridgeDxe] /root/kernels/ovmf-build-X64/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridge.c(550): !(((INTN)(RETURN_STATUS)(Status)) < 0)
>>
>> Doing some bisecting, before Qemu patch
>>
>>      8504f129450b ("i386/pc: relocate 4g start to 1T where applicable")
>>
>> this issue wasn't observed. And before this OVMF patch, the newer version
>> of Qemu doesn't have an issue.
>>
>> Also, if I add host-phys-bits=true to the Qemu -cpu parameter, then
>> the issue isn't observed regardless of Qemu/OVMF level.
>>
>> I'm hoping someone has an understanding of what is going on and what
>> can be done to fix it.
>>
> 
> Could someone look into this please? Gerd?

Looks like Gerd is already on it.

See https://bugzilla.tianocore.org/show_bug.cgi?id=4251

Thanks,
Tom