本文转载自 halfa (opens new window) 的博文 Boot from an EFI Shell (opens new window)，并进行了翻译。
今天启动 PVE 集群上的几个虚拟机的时候，出现了下图的报错。
报错是 BdsDxe: failed to load Boot0001 "UEFI QEMU QEMU HARDDISK" from PciRoot(0x0/Pci(0x1E,0x0)/Pci(0x1,0x0)/Pci(0x5,0x0)/Scsi(0x0,0x0): Not Found.。
引导失败以后，虚拟机尝试通过 PXE 引导，也失败了，最终回到了 EFI shell：
这台虚拟机原本应该从 VirtIO SCSI Controller 引导。图上报错看起来是因为 PCI 总线或者一个（虚拟）存储卡变化*，导致存储在 EFI NVRAM（也就是存储 UEFI 配置的地方）的引导入口（boot entry）指向了不存在的设备，所以引导失败了。
* 估计是它之前用的另一个虚拟控制器被我不小心重命名为了 VirtIO。
# 解决方案（临时）
下面是手动引导 EFI 文件的办法。想要修改 EFI 配置，你可以参考 EFI shell Cheat-sheet。
EFI shell 和大部分 shell 一样，可以通过 shift + pageUp / pageDown 来滚动屏幕。可以使用 exit 命令回到 EFI 管理界面，或者 reboot 命令重启。
下面的 shell 交互演示了如何加载硬盘、手动引导：
Shell>FS0:
FS0:\> ls
Directory of: FS0:\
09/22/2019 19:43 <DIR> 4,096 EFI
04/15/2020 20:51 10,668 NvVars
1 File(s) 10,668 bytes
1 Dir(s)
FS0:\> cd EFI
FS0:\EFI\> cd debian
FS0:\EFI\debian\> grub64.efi
# EFI shell Cheat-sheet
map命令输出分区和设备的映射表（类似于lsblk）。vol <VOL-NAME>会输出更多信息。- 输出引导选项列表：
FS0:\> bcfg boot dump -b
...
Option: 06. Variable: Boot0004
Desc - UEFI QEMU HARDDISK QM00001
DevPath - PciRoot(0x0)/Pci(0x1,0x1)/Ata(0x0)
Optional- Y
...
- 移动某个引导选项位置（同时顺移其它引导选项）
# 将选项 6 移动到选项 0 的位置（也就是第 1 位），同时顺移其它选项
FS0:\> bcfg boot mv 6 0
- 移除引导选项
FS0:\> bcfg boot rm 4
- 添加引导选项
FS0:\> bcfg boot add 1 FS0:\EFI\GRUB\grubx64.efi "GRUB"
Target = 0007.
bcfg: Add Boot0007 as 1
help命令的完整输出如下：
FS0:\> cat help.txt
alias - Displays, creates, or deletes UEFI Shell aliases.
attrib - Displays or modifies the attributes of files or directories.
bcfg - Manages the boot and driver options that are stored in NVRAM.
cd - Displays or changes the current directory.
cls - Clears the console output and optionally changes the background and foreground color.
comp - Compares the contents of two files on a byte-for-byte basis.
connect - Binds a driver to a specific device and starts the driver.
cp - Copies one or more files or directories to another location.
date - Displays and sets the current date for the system.
dblk - Displays one or more blocks from a block device.
devices - Displays the list of devices managed by UEFI drivers.
devtree - Displays the UEFI Driver Model compliant device tree.
dh - Displays the device handles in the UEFI environment.
disconnect - Disconnects one or more drivers from the specified devices.
dmem - Displays the contents of system or device memory.
dmpstore - Manages all UEFI variables.
drivers - Displays the UEFI driver list.
drvcfg - Invokes the driver configuration.
drvdiag - Invokes the Driver Diagnostics Protocol.
echo - Controls script file command echoing or displays a message.
edit - Provides a full screen text editor for ASCII or UCS-2 files.
eficompress - Compresses a file using UEFI Compression Algorithm.
efidecompress - Decompresses a file using UEFI Decompression Algorithm.
else - Identifies the code executed when 'if' is FALSE.
endfor - Ends a 'for' loop.
endif - Ends the block of a script controlled by an 'if' statement.
exit - Exits the UEFI Shell or the current script.
for - Starts a loop based on 'for' syntax.
getmtc - Gets the MTC from BootServices and displays it.
goto - Moves around the point of execution in a script.
help - Displays the UEFI Shell command list or verbose command help.
hexedit - Provides a full screen hex editor for files, block devices, or memory.
if - Executes commands in specified conditions.
ifconfig - Modifies the default IP address of the UEFI IPv4 Network Stack.
ifconfig6 - Displays or modifies IPv6 configuration for network interface.
load - Loads a UEFI driver into memory.
loadpcirom - Loads a PCI Option ROM.
ls - Lists the contents of a directory or file information.
map - Displays or defines file system mappings.
memmap - Displays the memory map maintained by the UEFI environment.
mkdir - Creates one or more new directories.
mm - Displays or modifies MEM/MMIO/IO/PCI/PCIE address space.
mode - Displays or changes the console output device mode.
mv - Moves one or more files to a destination within or between file systems.
openinfo - Displays the protocols and agents associated with a handle.
parse - Retrieves a value from a standard format output file.
pause - Pauses a script and waits for an operator to press a key.
pci - Displays PCI device list or PCI function configuration space and PCIe extended
configuration space.
ping - Ping the target host with an IPv4 stack.
ping6 - Ping a target machine with UEFI IPv6 network stack.
reconnect - Reconnects drivers to the specific device.
reset - Resets the system.
rm - Deletes one or more files or directories.
sermode - Sets serial port attributes.
set - Displays or modifies UEFI Shell environment variables.
setsize - Adjusts the size of a file.
setvar - Displays or modifies a UEFI variable.
shift - Shifts in-script parameter positions.
smbiosview - Displays SMBIOS information.
stall - Stalls the operation for a specified number of microseconds.
time - Displays or sets the current time for the system.
timezone - Displays or sets time zone information.
touch - Updates the filename timestamp with the current system date and time.
type - Sends the contents of a file to the standard output device.
unload - Unloads a driver image that was already loaded.
ver - Displays UEFI Firmware version information.
vol - Displays or modifies information about a disk volume.
Help usage:help [cmd|pattern|special] [-usage] [-verbose] [-section name][-b]
Reference: GRUB/EFI examples from the Archlinux Wiki (opens new window)