It refers to access to the root port device that doesn't exist in case we are dealing with RCiEP device. There can be specific case where RCiEP device has ARI extended capability ID (even though it's unsupported in this case). In such a case PciSearchDevice goes to CreatePciIoDevice through GatherDeviceInfo. And in this case parent is PCI_IO_DEVICE instance created from CreateRootBridge function, which isn't valid PCIe device and doesn't have specific bus, only a range of buses. In that case enumerator tries to use this instance to read operation using default 0 bus number, which isn't correct. Damian From: Wu, Hao A Sent: Tuesday, August 31, 2021 6:28 AM To: devel@edk2.groups.io; Wu, Hao A ; Bassa, Damian ; Ni, Ray Subject: RE: [edk2-devel] [PATCH] MdeModulePkg/PciBusDxe: Enumerator to check for RCiEP before looking for RP From: devel@edk2.groups.io > On Behalf Of Wu, Hao A Sent: Tuesday, August 31, 2021 12:25 PM To: devel@edk2.groups.io; Bassa, Damian > Subject: Re: [edk2-devel] [PATCH] MdeModulePkg/PciBusDxe: Enumerator to check for RCiEP before looking for RP Really sorry, Could you help to provide more information on the below statement? "undefined parent register accesses" Thanks in advance. Best Regards, Hao Wu From: devel@edk2.groups.io > On Behalf Of Bassa, Damian Sent: Tuesday, August 24, 2021 11:15 PM To: devel@edk2.groups.io Subject: [edk2-devel] [PATCH] MdeModulePkg/PciBusDxe: Enumerator to check for RCiEP before looking for RP Before trying to access parent root port to check ARI capabilities, enumerator should see if Endpoint device is not Root Complex integrated to avoid undefined parent register accesses in these cases. Signed-off-by: Damian Bassa damian.bassa@intel.com --- .../Bus/Pci/PciBusDxe/PciEnumeratorSupport.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c b/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c index db1b35f8ef..6451fb8af9 100644 --- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c +++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c @@ -2153,6 +2153,7 @@ CreatePciIoDevice ( PCI_IO_DEVICE *PciIoDevice; EFI_PCI_IO_PROTOCOL *PciIo; EFI_STATUS Status; + PCI_REG_PCIE_CAPABILITY Capability; PciIoDevice = AllocateZeroPool (sizeof (PCI_IO_DEVICE)); if (PciIoDevice == NULL) { @@ -2229,7 +2230,16 @@ CreatePciIoDevice ( return NULL; } - if (PcdGetBool (PcdAriSupport)) { + PciIo->Pci.Read ( + PciIo, + EfiPciIoWidthUint16, + PciIoDevice->PciExpressCapabilityOffset + OFFSET_OF (PCI_CAPABILITY_PCIEXP, Capability), + 1, + &Capability.Uint16 + ); + + if (PcdGetBool (PcdAriSupport) && + Capability.Bits.DevicePortType != PCIE_DEVICE_PORT_TYPE_ROOT_COMPLEX_INTEGRATED_ENDPOINT) { // // Check if the device is an ARI device. // -- 2.27.0.windows.1 ________________________________ Intel Technology Poland sp. z o.o. ul. Słowackiego 173 | 80-298 Gdańsk | Sąd Rejonowy Gdańsk Północ | VII Wydział Gospodarczy Krajowego Rejestru Sądowego - KRS 101882 | NIP 957-07-52-316 | Kapitał zakładowy 200.000 PLN. Ta wiadomość wraz z załącznikami jest przeznaczona dla określonego adresata i może zawierać informacje poufne. W razie przypadkowego otrzymania tej wiadomości, prosimy o powiadomienie nadawcy oraz trwałe jej usunięcie; jakiekolwiek przeglądanie lub rozpowszechnianie jest zabronione. This e-mail and any attachments may contain confidential material for the sole use of the intended recipient(s). If you are not the intended recipient, please contact the sender and delete all copies; any review or distribution by others is strictly prohibited. --------------------------------------------------------------------- Intel Technology Poland sp. z o.o. ul. Slowackiego 173 | 80-298 Gdansk | Sad Rejonowy Gdansk Polnoc | VII Wydzial Gospodarczy Krajowego Rejestru Sadowego - KRS 101882 | NIP 957-07-52-316 | Kapital zakladowy 200.000 PLN. Ta wiadomosc wraz z zalacznikami jest przeznaczona dla okreslonego adresata i moze zawierac informacje poufne. W razie przypadkowego otrzymania tej wiadomosci, prosimy o powiadomienie nadawcy oraz trwale jej usuniecie; jakiekolwiek przegladanie lub rozpowszechnianie jest zabronione. This e-mail and any attachments may contain confidential material for the sole use of the intended recipient(s). If you are not the intended recipient, please contact the sender and delete all copies; any review or distribution by others is strictly prohibited.