Re: EFI from usb HDD

[Michal Simek <michal.simek@xilinx.com>]

Hi,

On 6/10/21 11:47 AM, Heinrich Schuchardt wrote:
> On 6/10/21 10:44 AM, Michal Simek wrote:
>> Hi,
>>
>> I am playing with booting from USB via EFI. And I see very weird
>> behavior. I have burnt image with grub to USB flashdisk and I have
>> tested it on 3 zynqmp boards. zcu102, zcu104 and SOM Kria board.
>> On zcu102 grub is going to boot menu and everything is working fine as
>> expected.
>> On zcu104 and SOM Kria I am able to get grub not to menu. When I list
>> partitions in grub I see that only SDs are listed:
>> grub> ls
>> (hd0) (hd0,msdos1) (hd1) (hd1,msdos1)
> 
> Hello Michal,
> 
> thanks for sharing your observations.
> 
> What devices do hd0 and hd1 relate to?
> 
>>
>> On zcu102(working board) I also see usb(gpt) partitions and SD.
>> grub> ls
>> (hd0) (hd0,gpt2) (hd0,gpt1) (hd1) (hd1,msdos1)
>>
> 
> GPT and MBR partitioning are independent of the device type.
> 
>>
>> On zcu104 I see one more error message
>> "PE image measurement failed"
> 
> This is related to CONFIG_EFI_TCG2_PROTOCOL=y. Do you have a TPMv2? This
> will not stop disk enumeration.
> 
>> But I can't see it on SOM.
>>
>> U-Boot image is just the same for all boards. I am using generic
>> xilinx_zynqmp_virt_defconfig.
>>
>> When I compare DT description for USB between zcu102 and zcu104 they are
>> the same. SOM doesn't have usb enabled by default (but I enabled it) but
>> grub starts which means that communication with USB is fine.
>>
>> It is based on my latest patches available here.
>> u-boot/custodians/u-boot-microblaze.git (usb-efi-issue branch)
>>
>> Also when I list usb I see all partitions just fine.
>> ZynqMP> part list usb 0
>>
>> Partition Map for USB device 0  --   Partition Type: EFI
>>
>> Part    Start LBA       End LBA         Name
>>          Attributes
>>          Type GUID
>>          Partition GUID
>>    1     0x00000800      0x001007fe      "Microsoft basic data"
>>          attrs:  0x0000000000000000
>>          type:   ebd0a0a2-b9e5-4433-87c0-68b6b72699c7
>>          type:   data
>>          guid:   0e7f8b3d-296b-4720-be9d-c4687d3c4a77
>>    2     0x00100800      0x001197fe      "Microsoft basic data"
>>          attrs:  0x0000000000000000
>>          type:   ebd0a0a2-b9e5-4433-87c0-68b6b72699c7
>>          type:   data
>>          guid:   8892eddc-231a-4e6e-a5e1-c310f4482fb7
>>
>>
>> Do you have any idea why on one system is working fine to get to menu
>> and on others there is an issue to get all partitions even u-boot is
>> able to see them and can work with them.
>>
>> Thanks,
>> Michal
>>
> 
> Where is the GRUB binary? - If it is in EFI/boot/bootaa64.efi, it could
> be that the USB sub-system is simply not initialized yet when the boot
> manager is called by distroboot.
> 
> For testing partition detection in the UEFI sub-system it is enough to run
> 
>     efidebug devices
> 
> Until yesterday we had a problem with partition numbers >= 10, cf.
> 
> efi_loader: partition numbers are hexadecimal
> https://source.denx.de/u-boot/u-boot/-/commit/3dca77b1dc1b6dbf9c8b51572fe4b0553cef009f
> 
> 
> Block devices are enumerated in efi_disk_register(). Please, try to add
> debug output there to elucidate the problem.

I found where the problem is. First of all zcu102 didn't use the same
image as others (it wasn't updated properly).
When you have CONFIG_EFI_CAPSULE_ON_DISK_EARLY that efi_disk_register()
is called before usb block devices are detected and registered that's
why grub doesn't see them.
I was looking at adding usb start in preboot but preboot is called later.
How this should be solved? Any idea?

Thanks,
Michal