[PATCH v2 00/20] efi_loader: more tightly integrate UEFI disks to driver model
AKASHI Takahiro
takahiro.akashi at linaro.org
Thu Apr 14 10:39:00 CEST 2022
Hi Simon,
On Wed, Feb 16, 2022 at 12:00:10PM -0700, Simon Glass wrote:
> Hi Takahiro,
>
> On Wed, 16 Feb 2022 at 01:31, AKASHI Takahiro
> <takahiro.akashi at linaro.org> wrote:
> >
> > Hi Simon,
> >
> > On Mon, Feb 14, 2022 at 11:35:06AM +0900, AKASHI Takahiro wrote:
> > > Heinrich,
> > >
> > > On Thu, Feb 10, 2022 at 04:20:11PM +0100, Heinrich Schuchardt wrote:
> > > > On 2/10/22 09:11, AKASHI Takahiro wrote:
> > > > > Background:
> > > > > ===========
> > > > > The purpose of this patch is to reignite the discussion about how UEFI
> > > > > subystem would best be integrated into U-Boot driver model.
> > > > > In the past, I proposed a couple of patch series, the latest one[1],
> > > > > while Heinrich revealed his idea[2], and the approach taken here is
> > > > > something between them, with a focus on block device handlings.
> > > > >
> > > > > Disks in UEFI world:
> > > > > ====================
> > > > > In general in UEFI world, accessing to any device is performed through
> > > > > a 'protocol' interface which are installed to (or associated with) the device's
> > > > > UEFI handle (or an opaque pointer to UEFI object data). Protocols are
> > > > > implemented by either the UEFI system itself or UEFI drivers.
> > > > >
> > > > > For block IO's, it is a device which has EFI_BLOCK_IO_PROTOCOL (efi_disk
> > > > > hereafter). Currently, every efi_disk may have one of two origins:
> > > > >
> > > > > a.U-Boot's block devices or related partitions
> > > > > (lib/efi_loader/efi_disk.c)
> > > > > b.UEFI objects which are implemented as a block device by UEFI drivers.
> > > > > (lib/efi_driver/efi_block_device.c)
> > > > >
> > > > > All the efi_diskss as (a) will be enumerated and created only once at UEFI
> > > > > subsystem initialization (efi_disk_register()), which is triggered by
> > > > > first executing one of UEFI-related U-Boot commands, like "bootefi",
> > > > > "setenv -e" or "efidebug".
> > > > > EFI_BLOCK_IO_PROTOCOL is implemented by UEFI system using blk_desc(->ops)
> > > > > in the corresponding udevice(UCLASS_BLK).
> > > > >
> > > > > On the other hand, efi_disk as (b) will be created each time UEFI boot
> > > > > services' connect_controller() is executed in UEFI app which, as a (device)
> > > > > controller, gives the method to access the device's data,
> > > > > ie. EFI_BLOCK_IO_PROTOCOL.
> > > > >
> > > > > > > > more details >>>
> > > > > Internally, connect_controller() search for UEFI driver that can support
> > > > > this controller/protocol, 'efi_block' driver(UCLASS_EFI) in this case,
> > > > > then calls the driver's 'bind' interface, which eventually installs
> > > > > the controller's EFI_BLOCK_IO_PROTOCOL to efi_disk object.
> > > > > 'efi_block' driver also create a corresponding udevice(UCLASS_BLK) for
> > > > > * creating additional partitions efi_disk's, and
> > > > > * supporting a file system (EFI_SIMPLE_FILE_SYSTEM_PROTOCOL) on it.
> > > > > <<< <<<
> > > > >
> > > > > Issues:
> > > > > =======
> > > > > 1. While an efi_disk represents a device equally for either a whole disk
> > > > > or a partition in UEFI world, the driver model treats only a whole
> > > > > disk as a real block device or udevice(UCLASS_BLK).
> > > > >
> > > > > 2. efi_disk holds and makes use of "blk_desc" data even though blk_desc
> > > > > in plat_data is supposed to be private and not to be accessed outside
> > > > > the driver model.
> > > > > # This issue, though, exists for all the implementation of U-Boot
> > > > > # file systems as well.
> > > > >
> > > > > For efi_disk(a),
> > > > > 3. A block device can be enumerated dynamically by 'scanning' a device bus
> > > > > in U-Boot, but UEFI subsystem is not able to update efi_disks accordingly.
> > > > > For examples,
> > > > > => scsi rescan; efidebug devices
> > > > > => usb start; efidebug devices ... (A)
> > > > > (A) doesn't show any usb devices detected.
> > > > >
> > > > > => scsi rescan; efidebug boot add -b 0 TEST scsi 0:1 ...
> > > > > => scsi rescan ... (B)
> > > > > => bootefi bootmgr ... (C)
> > > > > (C) may de-reference a bogus blk_desc pointer which has been freed by (B).
> > > > > (Please note that "scsi rescan" removes all udevices/blk_desc and then
> > > > > re-create them even if nothing is changed on a bus.)
> > > > >
> > > > > For efi_disk(b),
> > > > > 4. A "controller (handle)", combined with efi_block driver, has no
> > > > > corresponding udevice as a parent of efi_disks in DM tree, unlike,
> > > > > say, a scsi controller, even though it provides methods for block io
> > > > > operations.
> > > > > 5. There is no way supported to remove efi_disk's even after
> > > > > disconnect_controller() is called.
> > > > >
> > > > >
> > > > > My approach:
> > > > > ============
> > > > > Due to functional differences in semantics, it would be difficult
> > > > > to identify "udevice" structure as a handle in UEFI world. Instead, we will
> > > > > have to somehow maintain a relationship between a udevice and a handle.
> > > > >
> > > > > 1-1. add a dedicated uclass, UCLASS_PARTITION, for partitions
> > > > > Currently, the uclass for partitions is not a UCLASS_BLK.
> > > > > It can be possible to define partitions as UCLASS_BLK
> > > > > (with IF_TYPE_PARTION?), but
> > > > > I'm afraid that it may introduce some chaos since udevice(UCLASS_BLK)
> > > > > is tightly coupled with 'struct blk_desc' data which is still used
> > > > > as a "structure to a whole disk" in a lot of interfaces.
> > > > > (I hope that you understand what it means.)
> > > > >
> > > > > In DM tree, a UCLASS_PARTITON instance has a UCLASS_BLK parent:
> > > > > For instance,
> > > > > UCLASS_SCSI --- UCLASS_BLK --- UCLASS_PARTITION
> > > > > (IF_TYPE_SCSI) |
> > > > > +- struct blk_desc +- struct disk_part
> > > > > +- scsi_blk_ops +- blk_part_ops
> > > > >
> > > > > 1-2. create partition udevices in the context of device_probe()
> > > > > part_init() is already called in blk_post_probe(). See the commit
> > > > > d0851c893706 ("blk: Call part_init() in the post_probe() method").
> > > > > Why not enumerate partitions as well in there.
> > > > >
> > > > > 2. add new block access interfaces, which takes a *udevice* as a target
> > > > > device, in U-Boot and use those functions to implement efi_disk
> > > > > operations (i.e. EFI_BLOCK_IO_PROTOCOL).
> > > > >
> > > > > 3-1. maintain a bi-directional link between a udevice and an efi_disk
> > > > > by adding
> > > > > - a UEFI handle pointer as a tag for a udevice
> > > > > - a udevice pointer in UEFI handle (in fact, in "struct efi_disk_obj")
> > > > >
> > > > > 3-2. synchronize the lifetime of efi_disk objects in UEFI world with
> > > > > the driver model using
> > > > > - event notification associated with device's probe/remove.
> > > > >
> > > > > 4. I have no solution to issue(4) and (5) yet.
> > > > >
> > > > >
> > > > > <<<Example DM tree on qemu-arm64>>>
> > > > > => dm tree
> > > > > Class Driver Name
> > > > > --------------------------------------------
> > > > > root root_driver root_driver
> > > > > ...
> > > > > pci pci_generic_ecam |-- pcie at 10000000
> > > > > pci_generi pci_generic_drv | |-- pci_0:0.0
> > > > > virtio virtio-pci.l | |-- virtio-pci.l#0
> > > > > ethernet virtio-net | | `-- virtio-net#32
> > > > > ahci ahci_pci | |-- ahci_pci
> > > > > scsi ahci_scsi | | `-- ahci_scsi
> > > > > blk scsi_blk | | |-- ahci_scsi.id0lun0
> > > > > partition blk_partition | | | |-- ahci_scsi.id0lun0:1
> > > > > partition blk_partition | | | `-- ahci_scsi.id0lun0:2
> > > > > blk scsi_blk | | `-- ahci_scsi.id1lun0
> > > > > partition blk_partition | | |-- ahci_scsi.id1lun0:1
> > > > > partition blk_partition | | `-- ahci_scsi.id1lun0:2
> > > > > usb xhci_pci | `-- xhci_pci
> > > > > usb_hub usb_hub | `-- usb_hub
> > > > > usb_dev_ge usb_dev_generic_drv | |-- generic_bus_0_dev_2
> > > > > usb_mass_s usb_mass_storage | `-- usb_mass_storage
> > > > > blk usb_storage_blk | `-- usb_mass_storage.lun0
> > > > > partition blk_partition | |-- usb_mass_storage.lun0:1
> > > > > partition blk_partition | `-- usb_mass_storage.lun0:2
> > > > > ...
> > > > > => efi devices
> > > > > Device Device Path
> > > > > ================ ====================
> > > > > 000000013eeea8d0 /VenHw()
> > > > > 000000013eeed810 /VenHw()/MAC(525252525252,1)
> > > > > 000000013eefc460 /VenHw()/Scsi(0,0)
> > > > > 000000013eefc5a0 /VenHw()/Scsi(0,0)/HD(1,GPT,ce86c5a7-b32a-488f-a346-88fe698e0edc,0x22,0x4c2a)
> > > > > 000000013eefe320 /VenHw()/Scsi(0,0)/HD(2,GPT,aa80aab9-33e6-42b6-b5db-def2cb8d7844,0x5000,0x1a800)
> > > > > 000000013eeff210 /VenHw()/Scsi(1,0)
> > > > > 000000013eeff390 /VenHw()/Scsi(1,0)/HD(1,GPT,ce86c5a7-b32a-488f-a346-88fe698e0edc,0x22,0x4c2a)
> > > > > 000000013eeff7d0 /VenHw()/Scsi(1,0)/HD(2,GPT,aa80aab9-33e6-42b6-b5db-def2cb8d7844,0x5000,0x1a800)
> > > > > 000000013ef04c20 /VenHw()/UsbClass(0x0,0x0,0x9,0x0,0x3)/UsbClass(0x46f4,0x1,0x0,0x0,0x0)
> > > > > 000000013ef04da0 /VenHw()/UsbClass(0x0,0x0,0x9,0x0,0x3)/UsbClass(0x46f4,0x1,0x0,0x0,0x0)/HD(1,0x01,0,0x0,0x99800)
> > > > > 000000013ef04f70 /VenHw()/UsbClass(0x0,0x0,0x9,0x0,0x3)/UsbClass(0x46f4,0x1,0x0,0x0,0x0)/HD(2,0x01,0,0x99800,0x1800)
> > > > >
> > > > >
> > > > > Patchs:
> > > > > =======
> > > > > For easy understandings, patches may be categorized into separate groups
> > > > > of changes.
> > > > >
> > > > > Patch#1-#7: DM: add device_probe() for later use of events
> > > > > Patch#8-#11: DM: add new features (tag and event notification)
> > > > > Patch#12-#16: UEFI: dynamically create/remove efi_disk's for a raw disk
> > > > > and its partitions
> > > > > For removal case, we may need more consideration since removing handles
> > > > > unconditionally may end up breaking integrity of handles
> > > > > (as some may still be held and referenced to by a UEFI app).
> > > > > Patch#17-#18: UEFI: use udevice read/write interfaces
> > > > > Patch#19-#20: UEFI: fix-up efi_driver, aligning with changes in DM integration
> > > > >
> > > > >
> > > > > [1] https://lists.denx.de/pipermail/u-boot/2019-February/357923.html
> > > > > [2] https://lists.denx.de/pipermail/u-boot/2021-June/452297.html
> > > >
> > > > This series does not pass Gitlab CI:
> > > >
> > > > See
> > > > https://source.denx.de/u-boot/custodians/u-boot-efi/-/jobs/391030
> > > > https://source.denx.de/u-boot/custodians/u-boot-efi/-/jobs/391031
> > >
> > > I have noticed those errors but I didn't think that they were related
> > > to my patch set initially as I didn't touch any code in gpt driver,
> > > android/avb nor video driver.
> > >
> > > > I will set the whole series to "changes requested"
> > > >
> > > > Please, run 'make tests' before resubmitting.
> > > >
> > > > Best regards
> > > >
> > > > Heinrich
> > > >
> > > > =================================== FAILURES
> > > > ===================================
> > > > ________________________________ test_gpt_write
> > > > ________________________________
> > > > test/py/tests/test_gpt.py:169: in test_gpt_write
> > > > assert 'Writing GPT: success!' in output
> > > > E AssertionError: assert 'Writing GPT: success!' in 'Writing GPT: Not
> > > > a block device: rng\r\r\nsuccess!'
> > >
> > > The reason of assertion failure here is that some log message was
> > > inserted in a output message although the test itself was finished
> > > successfully:
> > > "Writing GPT: success!" <== a correct output message
> > > ^
> > > "Not a block device: rng"
> > >
> > > Adding efi_disk_probe() as a callback to EVT_DM_POST_PROBE created
> > > this *log_info* message in dm_rng_read() <- get_rand_uuid() <-
> > > gen_rand_uuid_str() in "gpt write" command.
> > >
> > > We can fix this type of failure by the hack:
> > > ===8<===
> > > --- a/lib/efi_loader/efi_disk.c
> > > +++ b/lib/efi_loader/efi_disk.c
> > > @@ -612,8 +612,6 @@ static int efi_disk_probe(void *ctx, struct event *event)
> > >
> > > /* TODO: We won't support partitions in a partition */
> > > if (id != UCLASS_BLK) {
> > > - if (id != UCLASS_PARTITION)
> > > - log_info("Not a block device: %s\n", dev->name);
> > > return 0;
> > > }
> > > ===>8===
> > >
> > > I don't think, however, that it is a good thing that test results
> > > depend on console outputs, especially *log* messages.
> > >
> > > Furthermore, I don't know why we see *info*-level messages
> > > even under CONFIG_LOGLEVEL=4 (warning).
> > >
> > > > ----------------------------- Captured stdout call
> > > > -----------------------------
> > > > => host bind 0 /tmp/sandbox/test_gpt_disk_image.bin
> > > >
> > > > => => gpt write host 0 "name=all,size=0"
> > > >
> > > > Writing GPT: Not a block device: rng
> > > >
> > > > success!
> > > >
> > > > =>
> > > > ___________________ test_ut[ut_dm_dm_test_video_comp_bmp32]
> > > > ____________________
> > > > test/py/tests/test_ut.py:43: in test_ut
> > > > assert output.endswith('Failures: 0')
> > > > E AssertionError: assert False
> > > > E + where False = <built-in method endswith of str object at
> > > > 0x7fd72d2fc800>('Failures: 0')
> > > > E + where <built-in method endswith of str object at
> > > > 0x7fd72d2fc800> = 'Test: dm_test_video_comp_bmp32: video.c\r\r\nSDL
> > > > renderer does not exist\r\r\ntest/dm/video.c:88,
> > > > compress_frame_buff..._test_video_comp_bmp32(): 2024 ==
> > > > compress_frame_buffer(uts, dev): Expected 0x7e8 (2024), got 0x1
> > > > (1)\r\r\nFailures: 2'.endswith
> > > > ----------------------------- Captured stdout call
> > > > -----------------------------
> > > > => ut dm dm_test_video_comp_bmp32
> > > >
> > > > Test: dm_test_video_comp_bmp32: video.c
> > > >
> > > > SDL renderer does not exist
> > > >
> > > > test/dm/video.c:88, compress_frame_buffer(): !memcmp(uc_priv->fb,
> > > > uc_priv->copy_fb, uc_priv->fb_size): Copy framebuffer does not match fb
> > > >
> > > > test/dm/video.c:484, dm_test_video_comp_bmp32(): 2024 ==
> > > > compress_frame_buffer(uts, dev): Expected 0x7e8 (2024), got 0x1 (1)
> > > >
> > > > Failures: 2
> > >
> > > I don't know yet why this happened.
> >
> > It seems that this error happened simply because more ut DM tests were
> > added. Added here are DM tag tests (in my patch#14 of 20).
> >
> > But what type of test is added doesn't matter. When a total number
> > of ut DM tests is increased (and exceeds some limit?), one of tests
> > (either video or another) may unexpectedly fail.
> > For instance, I randomly picked up one test from test/dm/gpio.c and
> > commented it out, and then I didn't see any error in test_ut.py.
> >
> > So I suspect there may be some problem with pytest framework.
> >
> > Do you have any clue, Simon?
>
> Yes I believe it is a problem with memory allocation. Perhaps we run
> out of memory, or something else goes wrong. The value:
>
> #define top (av_[2])
>
> seems to get corrupted. I did spent some time trying to figure out
> what it was but have not found it yet.
Do you have any new insight here?
I still see the same problem even after rebasing my DM-integration patches
to v2022.07 branch and I want to fix the issue.
-Takahiro Akashi
> Regards,
> Simon
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