Re: [PATCH v1] efi: make sure EFI disk controllers are connected when discovering devices

[Alexander Graf]

On 08.02.22 11:56, Renaud Métrich wrote:
> When efi.quickboot is enabled on VMWare (which is the default for
> hardware release 16 and later), it may happen that not all EFI devices
> are connected. Due to this, browsing the devices in make_devices() just
> fails to find devices, in particular partitions for a given disk.
> This typically happens when network booting, then trying to chainload to
> local disk (this is used in deployment tools such as Red Hat Satellite).
>
> This patch makes sure all controllers are connected before enumerating
> the disks. It blindly calls the EFI ConnectController function with
> recursive option and just ignores the result, which is 0 (EFI_SUCCESS)
> or 14 (EFI_NOT_FOUND) when the handle is not a controller.
>
> Signed-off-by: Renaud Métrich <rmetrich@redhat.com>


Isn't this going to slow down most normal boots? Is there a way we can 
only try harder to find devices once the "fast path" is exhausted? This 
could be useful for other systems as well, where we could delay probing 
for floppy drives until such a point.

I'm thinking of something akin to udev_settle. You typically search for 
devices by UUID. If you find the UUID, all is good. If you don't, invoke 
the "try to find additional devices" path.


Alex


> ---
>   grub-core/disk/efi/efidisk.c | 10 ++++++++++
>   grub-core/kern/efi/efi.c     | 13 +++++++++++++
>   include/grub/efi/efi.h       |  5 +++++
>   3 files changed, 28 insertions(+)
>
> diff --git a/grub-core/disk/efi/efidisk.c b/grub-core/disk/efi/efidisk.c
> index f077b5f55..0b16c3868 100644
> --- a/grub-core/disk/efi/efidisk.c
> +++ b/grub-core/disk/efi/efidisk.c
> @@ -387,6 +387,16 @@ static void
>   enumerate_disks (void)
>   {
>     struct grub_efidisk_data *devices;
> +  unsigned i;
> +  grub_efi_handle_t *handles;
> +  grub_efi_uintn_t num_handles;
> +
> +  /* Prior to enumerating, make sure all EFI devices are connected */
> +
> +  handles = grub_efi_locate_handle (GRUB_EFI_ALL_HANDLES,
> +                                   NULL, NULL, &num_handles);
> +  for (i = 0; i < num_handles; i++)
> +    (void) grub_efi_connect_controller(handles[i], NULL, NULL, 1);
>   
>     devices = make_devices ();
>     if (! devices)
> diff --git a/grub-core/kern/efi/efi.c b/grub-core/kern/efi/efi.c
> index 18858c327..bdfff3dd0 100644
> --- a/grub-core/kern/efi/efi.c
> +++ b/grub-core/kern/efi/efi.c
> @@ -95,6 +95,19 @@ grub_efi_locate_handle (grub_efi_locate_search_type_t 
> search_type,
>     return buffer;
>   }
>   
> +grub_efi_status_t
> +grub_efi_connect_controller (grub_efi_handle_t controller_handle,
> +                            grub_efi_handle_t *driver_image_handle,
> +                            grub_efi_device_path_protocol_t 
> *remaining_device_path,
> +                            grub_efi_boolean_t recursive)
> +{
> +  grub_efi_boot_services_t *b;
> +
> +  b = grub_efi_system_table->boot_services;
> +  return efi_call_4 (b->connect_controller, controller_handle,
> +                    driver_image_handle, remaining_device_path, recursive);
> +}
> +
>   void *
>   grub_efi_open_protocol (grub_efi_handle_t handle,
>                         grub_efi_guid_t *protocol,
> diff --git a/include/grub/efi/efi.h b/include/grub/efi/efi.h
> index fc723962d..62dbd9788 100644
> --- a/include/grub/efi/efi.h
> +++ b/include/grub/efi/efi.h
> @@ -32,6 +32,11 @@ EXPORT_FUNC(grub_efi_locate_handle) 
> (grub_efi_locate_search_type_t search_type,
>                                      grub_efi_guid_t *protocol,
>                                      void *search_key,
>                                      grub_efi_uintn_t *num_handles);
> +grub_efi_status_t
> +EXPORT_FUNC(grub_efi_connect_controller) (grub_efi_handle_t controller_handle,
> +                                         grub_efi_handle_t 
> *driver_image_handle,
> +                                         grub_efi_device_path_protocol_t 
> *remaining_device_path,
> +                                         grub_efi_boolean_t recursive);
>   void *EXPORT_FUNC(grub_efi_open_protocol) (grub_efi_handle_t handle,
>                                            grub_efi_guid_t *protocol,
>                                            grub_efi_uint32_t attributes);