From 8e5720fdf59f160aa57780c6043601a5e039a72a Mon Sep 17 00:00:00 2001 From: Stefan Reiter Date: Wed, 6 Oct 2021 17:52:10 +0200 Subject: [PATCH] qm: add note about secure boot and new efidisk behaviour Signed-off-by: Stefan Reiter --- qm.adoc | 30 ++++++++++++++++++++++++------ 1 file changed, 24 insertions(+), 6 deletions(-) diff --git a/qm.adoc b/qm.adoc index 80734e3..93576c7 100644 --- a/qm.adoc +++ b/qm.adoc @@ -733,10 +733,13 @@ the operating system. By default QEMU uses *SeaBIOS* for this, which is an open-source, x86 BIOS implementation. SeaBIOS is a good choice for most standard setups. -There are, however, some scenarios in which a BIOS is not a good firmware -to boot from, e.g. if you want to do VGA passthrough. footnote:[Alex Williamson has a very good blog entry about this. -https://vfio.blogspot.co.at/2014/08/primary-graphics-assignment-without-vga.html] -In such cases, you should rather use *OVMF*, which is an open-source UEFI implementation. footnote:[See the OVMF Project https://github.com/tianocore/tianocore.github.io/wiki/OVMF] +Some operating systems (such as Windows 11) may require use of an UEFI +compatible implementation instead. In such cases, you must rather use *OVMF*, +which is an open-source UEFI implementation. footnote:[See the OVMF Project https://github.com/tianocore/tianocore.github.io/wiki/OVMF] + +There are other scenarios in which a BIOS is not a good firmware to boot from, +e.g. if you want to do VGA passthrough. footnote:[Alex Williamson has a very +good blog entry about this https://vfio.blogspot.co.at/2014/08/primary-graphics-assignment-without-vga.html] If you want to use OVMF, there are several things to consider: @@ -745,15 +748,30 @@ This disk will be included in backups and snapshots, and there can only be one. You can create such a disk with the following command: - qm set -efidisk0 :1,format= + qm set -efidisk0 :1,format=,efitype=4m,pre-enrolled-keys=1 Where ** is the storage where you want to have the disk, and ** is a format which the storage supports. Alternatively, you can create such a disk through the web interface with 'Add' -> 'EFI Disk' in the hardware section of a VM. +The *efitype* option specifies which version of the OVMF firmware should be +used. For new VMs, this should always be '4m', as it supports Secure Boot and +has more space allocated to support future development (this is the default in +the GUI). + +*pre-enroll-keys* specifies if the efidisk should come pre-loaded with +distribution-specific and Microsoft Standard Secure Boot keys. It also enables +Secure Boot by default (though it can still be disabled in the OVMF menu within +the VM). + +NOTE: If you want to start using Secure Boot in an existing VM (that still uses +a '2m' efidisk), you need to recreate the efidisk. To do so, delete the old one +(`qm set -delete efidisk0`) and add a new one as described above. This +will reset any custom configurations you have made in the OVMF menu! + When using OVMF with a virtual display (without VGA passthrough), -you need to set the client resolution in the OVMF menu(which you can reach +you need to set the client resolution in the OVMF menu (which you can reach with a press of the ESC button during boot), or you have to choose SPICE as the display type. -- 2.39.2