Messages in this thread | | | Date | Thu, 24 Nov 2022 08:26:38 -0600 | Subject | Re: [PATCH 0/2] Map initrd as encrypted when relocating if SME is enabled | From | Tom Lendacky <> |
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On 11/24/22 03:12, Zelin Deng wrote: > I found an issue on SME enabled AMD machine when initrd is relocated if > it was located in e820 reserved area. > For example key dmesg output: > ... > [mem 0x000000005aafe000-0x000000006005ffff] reserved //e820 mapping > Move RAMDISK from [mem 0x5aafe000-0x5ccd5167] //relocate_initrd() > ... > > Early initrd will be copied by copy_from_early_mem() which will clear > encrypted pgprot flag as initrd source address is not in kernel usable > area. As initrd has been encrypted at earlier stage, encrypted data is > copied, which leads new initrd cannot be unpacked, then rootfs cannot be > mounted.
This is actually a bug in Grub where the kernel and initrd was moved out of loader_code/data and into runtime_service_code/data. This commit has since been reverted because it goes against the UEFI specification. It was a small window, but the bad version was picked up by some distros. No need for a kernel change, please update your version of Grub.
Thanks, Tom
> dmesg output: > ... > [ 11.296725] Trying to unpack rootfs image as initramfs... > [ 11.302127] Initramfs unpacking failed: invalid magic at start of compressed archive > ... > [ 16.698152] /dev/root: Can't open blockdev > [ 16.702255] VFS: Cannot open root device "PARTUUID=0ad58d87-05c7-43f8-b147-93140ad315e5" or unknown-block(0,0): error -6 > [ 16.713114] Please append a correct "root=" boot option; here are the available partitions: > [ 16.721462] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0) > [ 16.729716] CPU: 9 PID: 1 Comm: swapper/0 Not tainted 6.1.0-rc5-next-20221114 #3 > [ 16.737099] Hardware name: AMD Corporation DAYTONA_X/DAYTONA_X, BIOS RYM1008B 01/19/2022 > [ 16.745175] Call Trace: > [ 16.747623] <TASK> > [ 16.749727] dump_stack_lvl+0x38/0x4c > [ 16.753393] panic+0xfb/0x28a > [ 16.771999] ? _printk+0x4c/0x52 > [ 16.775224] mount_block_root+0x143/0x1dd > [ 16.779237] prepare_namespace+0x13f/0x16e > [ 16.783334] kernel_init_freeable+0x15a/0x164 > [ 16.787687] ? __pfx_kernel_init+0x10/0x10 > [ 16.791785] kernel_init+0x1a/0x130 > [ 16.795268] ret_from_fork+0x29/0x50 > [ 16.798840] </TASK> > > To fix this issue, early initrd must be mapped as encrypted when it is > being relocated. > > Zelin Deng (2): > mm/early_ioremap.c: Always build early_memremap_prot() in x86 > x86/setup: Preserve _ENC flag when initrd is being relocated > > arch/x86/Kconfig | 1 + > arch/x86/kernel/setup.c | 30 ++++++++++++++++++++++++++++- > include/asm-generic/early_ioremap.h | 6 ------ > mm/early_ioremap.c | 21 -------------------- > 4 files changed, 30 insertions(+), 28 deletions(-) >
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