让UEFI支持btrfs#

装系统的时候如果要efi启动的话，启动程序文件要放在FAT格式的分区(或者有的电脑也可以放在NTFS的分区里)，所以如果系统盘不是这个格式的话还要专门划一个esp分区来存放EFI启动文件。那么能不能把EFI启动文件放在btrfs上呢？

我了解折腾了下，UEFI之所以好像叫什么可扩展固件接口，就是因为它可扩展，它跟操作系统有点类似(也许就是一个操作系统”)，它有类似C:盘D<盘的盘符>，不过叫FS0: FS1:，并且也有驱动程序并且可以加载驱动，其中就有文件系统的驱动程序，并且系统的EFI启动程序就相当于UEFI的可执行程序啦，并且还都是PE格式哦。

那么能不能加载btrfs的驱动呢？rEFInd就有好多文件系统的驱动，(没错，EFI启动程序也可以用UEFI”系统”的接口打开文件，rEFInd直接让”系统”加载了文件系统驱动然后再打开文件的，…，嗯rEFInd好像是链式启动，quibble应该就要打开文件了吧)

那么就手动加载它的驱动试试呗

qemu 启动

1
#!/bin/env zsh
2
@() { __+=" $@" ; }
3

4
@ qemu-system-x86_64
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@  -m 16G -object memory-backend-file,id=mem,size=16G,mem-path=/dev/shm,share=on -numa node,memdev=mem
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@  -smp cpus=8,sockets=1,cores=8,threads=1
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@  -bios /usr/share/edk2/x64/OVMF.4m.fd
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@  -cpu host
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@  -machine q35
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@  -enable-kvm
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@  -netdev tap,id=netwan,ifname=qemu-tap-test,script=no,downscript=no -device virtio-net,netdev=netwan,mac=52:55:57:00:00:00
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@  -drive file=.qcow2,format=qcow2
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@  -boot menu=on
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@  -serial stdio
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@  -chardev socket,id=char1,path=virtiofs.socket -device vhost-user-fs-pci,queue-size=1024,chardev=char1,tag=virtiofs
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/usr/lib/virtiofsd --socket-path=virtiofs.socket -o source=virtiofs -o cache=always &
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exec eval $__ $@

windows有cmd，linux下有bash,zsh，UEFI下也有个EFI Internal Shell的程序

UEFI Interactive Shell v2.2

EDK II

UEFI v2.70 (EDK II, 0x00010000)

Mapping table

1
  FS0: Alias(s):F1:
2

3
      PciRoot(0x0)/Pci(0x3,0x0)
4

5
 BLK0: Alias(s):
6

7
      PciRoot(0x0)/Pci(0x1F,0x2)/Sata(0x0,0xFFFF,0x0)
8

9
 BLK1: Alias(s):
10

11
      PciRoot(0x0)/Pci(0x1F,0x2)/Sata(0x2,0xFFFF,0x0)

Press ESC in 1 seconds to skip startup.nsh or any other key to continue.

Shell>

mode 调整分辨率

Shell> mode

Available modes for console output device.

Col 80 Row 25

Col 100 Row 31 *

Shell> mode 100 31

map看盘符

Shell> map

Mapping table

1
  FS0: Alias(s):F1:
2

3
      PciRoot(0x0)/Pci(0x3,0x0)
4

5
 BLK0: Alias(s):
6

7
      PciRoot(0x0)/Pci(0x1F,0x2)/Sata(0x0,0xFFFF,0x0)
8

9
 BLK1: Alias(s):
10

11
      PciRoot(0x0)/Pci(0x1F,0x2)/Sata(0x2,0xFFFF,0x0)

dir或ls命令能看到里面的文件

Shell> ls fs0:

Directory of: fs0:\

01/01/1970 00<00>

r 0 .

01/01/1970 00<00> 62,840 btrfs_x64.efi

01/01/1970 00<00> 12,477 NvVars

1
      2 File(s)      75,317 bytes
2

3
      1 Dir(s)

load加载驱动

Shell> load fs0:\btrfs_x64.efi

Image ‘FS0:\btrfs_x64.efi’ loaded at 7D7F1000 - Success

drivers查看加载的驱动列表

Shell> drivers

DRV	VERSION	TYPE	CFG	DING	#D	#C	DRIVER NAME	IMAGE NAME
5E	0000000A	B	-	-	1	7	PCI Bus Driver	PciBusDxe
60	00000010	?	-	-	-	-	Virtio PCI Driver	VirtioPciDeviceDxe
61	00000010	D	-	-	1	-	Virtio 1.0 PCI Driver	Virtio10
62	00000010	?	-	-	-	-	Virtio Block Driver	VirtioBlkDxe
63	00000010	?	-	-	-	-	Virtio SCSI Host Driver	VirtioScsiDxe
64	00000010	?	-	-	-	-	Virtio Serial Driver	VirtioSerialDxe
65	0000000A	D	-	-	2	-	Platform Console Management Driver	ConPlatformDxe
66	0000000A	D	-	-	2	-	Platform Console Management Driver	ConPlatformDxe
67	0000000A	B	-	-	2	2	Console Splitter Driver	ConSplitterDxe
68	0000000A	?	-	-	-	-	Console Splitter Driver	ConSplitterDxe
69	0000000A	?	-	-	-	-	Console Splitter Driver	ConSplitterDxe
6A	0000000A	B	-	-	2	2	Console Splitter Driver	ConSplitterDxe
6B	0000000A	B	-	-	1	1	Console Splitter Driver	ConSplitterDxe
6F	0000000A	D	-	-	1	-	Graphics Console Driver	GraphicsConsoleDxe
70	0000000A	B	-	-	1	1	Serial Terminal Driver	TerminalDxe
71	0000000A	D	-	-	2	-	Generic Disk I/O Driver	DiskIoDxe
72	0000000B	?	-	-	-	-	Partition Driver(MBR/GPT/El Torito)	PartitionDxe
75	0000000A	B	-	-	1	1	SCSI Bus Driver	ScsiBus
76	0000000A	D	-	-	1	-	Scsi Disk Driver	ScsiDisk
77	0000000A	D	-	-	1	-	Sata Controller Init Driver	SataController
78	00000010	D	-	-	1	-	AtaAtapiPassThru Driver	AtaAtapiPassThruDxe
79	00000010	B	-	-	1	1	ATA Bus Driver	AtaBusDxe
7A	00000010	?	-	-	-	-	NVM Express Driver	NvmExpressDxe
7B	00000010	B	-	-	1	3	OVMF Sio Bus Driver	SioBusDxe
7C	0000000A	B	-	-	1	1	PCI SIO Serial Driver	PciSioSerialDxe
7D	0000000A	D	-	-	1	-	PS/2 Keyboard Driver	Ps2KeyboardDxe
80	0000000A	?	-	-	-	-	FAT File System Driver	Fat
81	00000010	?	-	-	-	-	UDF File System Driver	UdfDxe
82	00000010	D	-	-	1	-	Virtio Filesystem Driver	VirtioFsDxe
85	0000000A	?	-	-	-	-	Simple Network Protocol Driver	SnpDxe
86	0000000A	B	-	-	1	1	VLAN Configuration Driver	VlanConfigDxe
87	0000000A	B	-	-	1	3	MNP Network Service Driver	MnpDxe
88	0000000A	B	-	-	1	1	ARP Network Service Driver	ArpDxe
89	0000000A	B	-	-	1	2	DHCP Protocol Driver	Dhcp4Dxe
8A	0000000A	B	-	-	2	12	IP4 Network Service Driver	Ip4Dxe
8B	0000000A	B	-	-	7	12	UDP Network Service Driver	Udp4Dxe
8C	0000000A	B	-	-	2	2	MTFTP4 Network Service	Mtftp4Dxe
8D	0000000A	B	-	-	1	2	DHCP6 Protocol Driver	Dhcp6Dxe
8E	0000000A	B	-	-	2	12	IP6 Network Service Driver	Ip6Dxe
8F	0000000A	B	-	-	6	10	UDP6 Network Service Driver	Udp6Dxe
90	0000000A	B	-	-	1	1	MTFTP6 Network Service Driver	Mtftp6Dxe
91	0000000A	B	-	-	8	1	UEFI PXE Base Code Driver	UefiPxeBcDxe
92	0000000A	B	-	-	7	1	UEFI PXE Base Code Driver	UefiPxeBcDxe
95	00000000	D	-	-	1	-	DNS Network Service Driver	DnsDxe
96	00000000	D	-	-	1	-	DNS Network Service Driver	DnsDxe
97	0000000A	D	-	-	1	-	HttpDxe	HttpDxe
98	0000000A	D	-	-	1	-	HttpDxe	HttpDxe
99	0000000A	B	-	-	2	1	UEFI HTTP Boot Driver	HttpBootDxe
9A	0000000A	B	-	-	3	1	UEFI HTTP Boot Driver	HttpBootDxe
9B	0000000A	D	-	-	1	-	iSCSI Driver	IScsiDxe
9C	0000000A	D	-	-	1	-	iSCSI Driver	IScsiDxe
9E	00000010	?	-	-	-	-	Virtio Network Driver	VirtioNetDxe
9F	00000020	?	-	-	-	-	Usb Uhci Driver	UhciDxe
A0	00000030	?	-	-	-	-	Usb Ehci Driver	EhciDxe
A1	00000030	?	-	-	-	-	Usb Xhci Driver	XhciDxe
A2	0000000A	?	-	-	-	-	Usb Bus Driver	UsbBusDxe
A3	0000000A	?	-	-	-	-	Usb Keyboard Driver	UsbKbDxe
A4	00000011	?	-	-	-	-	Usb Mass Storage Driver	UsbMassStorageDxe
A5	00000010	B	-	-	1	1	QEMU Video Driver	QemuVideoDxe
A6	00000010	?	-	-	-	-	Virtio GPU Driver	VirtioGpuDxe
A7	00000010	?	-	-	-	-	Virtio Random Number Generator Driv	VirtioRngDxe
A8	0000000A	B	-	-	3	4	TCP Network Service Driver	TcpDxe
A9	0000000A	B	-	-	3	4	TCP Network Service Driver	TcpDxe
B5	017D5C56	B	-	-	2	2	1af41000.efidrv	Offset(0x10E00,0x273FF)
FF	00000010	D	-	-	1	-	rEFInd 0.14.2 btrfs File System Dri	\btrfs_x64.efi

map -r重设盘符

Shell> map -r

Mapping table

1
  FS1: Alias(s):F1:
2

3
      PciRoot(0x0)/Pci(0x3,0x0)
4

5
  FS0: Alias(s):F0a65535a:;BLK0:
6

7
      PciRoot(0x0)/Pci(0x1F,0x2)/Sata(0x0,0xFFFF,0x0)
8

9
 BLK1: Alias(s):
10

11
      PciRoot(0x0)/Pci(0x1F,0x2)/Sata(0x2,0xFFFF

可以看到文件系统被识别了 (当然盘符也重新分配了)

那么运行一下呢 (没错，这里的程序也可以有命令行参数哦)

Shell> fs0:

FS0:> boot\vmlinuz-linux initrd=boot\initramfs-linux-fallback.img root=UUID=59004200-5900-3100-3300-300036000000 rw splash

启动成功了

edk2ovmf的设置里可以设置自动加载驱动哦

既然开机会自动识别btrfs文件系统，那么把btrfs上的EFI启动程序添加到启动列表呢

或者进linux后运行 efibootmgr -c -d /dev/sda -L 'Arch Linux' -l '/boot/vmlinuz-linux' --unicode "initrd=/boot/initramfs-linux-fallback.img root=UUID=59004200-5900-3100-3300-300036000000 rw splash" # -p 1

• -c代表创建
• -d后面是硬盘
• -p是分区数，如果没有分区就没有p参数
• -L名称
• -l文件路径(对于分区而言)，会自动转换斜杠
• --unicode 给EFI启动程序的参数

正常启动

但是这个驱动还是要在别的分区上的才能被加载

那么为什么FAT文件系统就可以直接识别呢？

用UEFITool打开固件，发现原来内嵌了FAT的驱动

那么怎么把btrfs驱动也内嵌进入呢？

发现这里相当于结构体，有属性和内容

其中这些是操作”结构体”

• Extract as is… Ctrl+E
• Insert into… Ctrl+l
• Insert before… Ctrl+Alt+|
• Insert after… Ctrl+Shift+|
• Replace as is… Ctrl+R
• Remove Ctrl+Del

其中这些是操作”内容”

• Extract body… Ctrl+Shift+E
• Replace body… Ctrl+Shift+R

然后这又相当于List与元素的区别

• Type显示为File(导出导入时默认为ffs后缀)的为List
• Type显示为Section(导出导入时默认为sct后缀)的为元素

那就把btrfs驱动也嵌入呗

1. 先把ffs结构体导出，用16进制编辑器改个GUID(前面的字节)，再找个地方插入
2. 把 PE32 image section 的内容替换成btrfs驱动
3. User interface section对应右边的Text，还有Version section，好像是给自己看的（嗯好像drivers也会显示，不过那也是给自己看的嘛～），好像改不改都行，(好像直接删掉也行)，可以导出内容用16进制编辑器修改再导入
4. 如果有DXE dependency section的要移除，否则好像不会自动加载，具体的我也不懂

然后保存并把qemu的bios参数选择为修改的固件就可以把esp分区删了，btrfs就能当esp分区啦！连分区都不用啦！

注：

• 这个驱动对于btrfs是只读的，不像FAT那样是可读写的。
• 如果加载多个同一种格式的文件系统驱动也只会有一个驱动接管分区。rEFInd的btrfs驱动与quibble暂不兼容，导致quibble无法启动btrfs上的windows。quibble的btrfs驱动与Linux内核的UKI暂不兼容，导致Linux内核的UKI功能无法找到initrd参数的initrd。