Branch: refs/heads/master
Home: https://github.com/tianocore/edk2
Commit: 82808b422617ea5d1e62f5c5741eb8ce9dff4a7b
https://github.com/tianocore/edk2/commit/82808b422617ea5d1e62f5c5741eb8ce9dff4a7b
Author: Laszlo Ersek <[email protected]>
Date: 2020-06-16 (Tue, 16 Jun 2020)
Changed paths:
M OvmfPkg/OvmfPkgIa32.dsc
M OvmfPkg/OvmfPkgIa32X64.dsc
M OvmfPkg/OvmfPkgX64.dsc
Log Message:
-----------
Revert "OvmfPkg: use generic QEMU image loader for secure boot enabled ..."
This reverts commit ced77332cab626f35fbdb36630be27303d289d79.
The command
virt-install --location NETWORK-URL
downloads the vmlinuz and initrd files from the remote OS tree, and passes
them to the guest firmware via fw_cfg.
When used with IA32 / X64 guests, virt-install expects the guest firmware
to do two things, at the same time:
- launch the fw_cfg kernel image even if the latter does not pass SB
verification (SB checking is supposed to be bypassed entirely in favor
of the Linux/x86 Boot Protocol),
- still let the guest kernel perceive SB as enabled.
Commit ced77332cab6 prevented this, by removing the Linux/x86 Boot
Protocol from such an OVMF image that was built with SECURE_BOOT_ENALBE.
While that's the right thing in theory, in practice "virt-install
--location NETWORK-URL" is entrenched, and we shouldn't break it.
We can tolerate the Linux/x86 Boot Protocol as a one-of-a-kind SB bypass
for direct-booted kernels, because:
- the fw_cfg content comes from QEMU, and the guest is already at QEMU's
mercy,
- in the guest, OS boots after the initial installation will use "shim"
rather than an fw_cfg kernel, which we can consider somewhat similar to
"Audit Mode / Deployed Mode" (~ trust for install, lock down after).
Cc: Ard Biesheuvel <[email protected]>
Cc: Jordan Justen <[email protected]>
Cc: Philippe Mathieu-Daudé <[email protected]>
Signed-off-by: Laszlo Ersek <[email protected]>
Acked-by: Ard Biesheuvel <[email protected]>
Message-Id: <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
[[email protected]: truncate the subject line, originally auto-generated
by git-revert, to pacify PatchCheck.py]
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