Public bug reported: Launching a libvirt vm with a UEFI boot with PCI cards (e.g. PCI passthrough of GPU cards) results in a black screen and no boot sequence at all. This is due to limitations in UEFI Bios boot code (OVMF) which limits to 32GB the max memory mapping, so using GPUs that owns more memory than 32GB (summing up all the GPUs attached) the UEFI boot will fail to start at all.
Following the documentation, latest OVMF has a special flag that can be used to ask to UEFI to allow more than 32GB mem alloc to PCI memory map ( https://edk2.groups.io/g/discuss/topic/59340711 ) which can be specified into the domain XML file for the VM. The attached patches are a workaround to allow using UEFI with GPUs (tested on a Rocky 9.x with 4 nVIDIA V100 SXM2 cards, with a total of 128GB of pci memory map). The patch tries to sum-up from the host the needed memory aperture and tries to understand if the current OVMF release has the needed options (this should be enhanced further). HTH ** Affects: nova Importance: Undecided Status: New ** Tags: gpu libvirt uefi ** Patch added: "GIT diff result from latest nova git repository master" https://bugs.launchpad.net/bugs/2043985/+attachment/5721200/+files/diff_latest_nova.diff -- You received this bug notification because you are a member of Yahoo! Engineering Team, which is subscribed to OpenStack Compute (nova). https://bugs.launchpad.net/bugs/2043985 Title: Cannot start a UEFI vm when pci memory mapped exceed 32GB Status in OpenStack Compute (nova): New Bug description: Launching a libvirt vm with a UEFI boot with PCI cards (e.g. PCI passthrough of GPU cards) results in a black screen and no boot sequence at all. This is due to limitations in UEFI Bios boot code (OVMF) which limits to 32GB the max memory mapping, so using GPUs that owns more memory than 32GB (summing up all the GPUs attached) the UEFI boot will fail to start at all. Following the documentation, latest OVMF has a special flag that can be used to ask to UEFI to allow more than 32GB mem alloc to PCI memory map ( https://edk2.groups.io/g/discuss/topic/59340711 ) which can be specified into the domain XML file for the VM. The attached patches are a workaround to allow using UEFI with GPUs (tested on a Rocky 9.x with 4 nVIDIA V100 SXM2 cards, with a total of 128GB of pci memory map). The patch tries to sum-up from the host the needed memory aperture and tries to understand if the current OVMF release has the needed options (this should be enhanced further). HTH To manage notifications about this bug go to: https://bugs.launchpad.net/nova/+bug/2043985/+subscriptions -- Mailing list: https://launchpad.net/~yahoo-eng-team Post to : [email protected] Unsubscribe : https://launchpad.net/~yahoo-eng-team More help : https://help.launchpad.net/ListHelp
