EFI from usb HDD

[Michal Simek]

On 6/10/21 12:51 PM, Heinrich Schuchardt wrote:
> On 6/10/21 12:04 PM, Michal Simek wrote:
>> 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.
> 
> The problem is CONFIG_EFI_SETUP_EARLY=y required by
> CONFIG_EFI_CAPSULE_ON_DISK_EARLY.
> 
> Why is USB initialized later then MMC?

It is not just usb. SCSI/sata are behaving in the same way too.

> 
> Overall we have a deficiency in the UEFI implementation in that we
> cannot deal with block devices added or removed after initialization.
> 
> Here integration with the driver model is missing.

Right. And also there are commands which can create MBR partitions and I
expect when you write image to SD and then run rescan or so you could
get other partitions too.
Maybe hook via part_init()? with removing efi_disk_register.

> 
>> I was looking at adding usb start in preboot but preboot is called later.
>> How this should be solved? Any idea?
>>
>> Thanks,
>> Michal
>>
>>
> +cc Sughosh, Takahiro (who have developed the capsule code)

Thanks,
Michal