Re: [PATCH v3 2/2] efi: new 'connectefi' command

[Glenn Washburn]

On Tue, 15 Feb 2022 14:05:22 +0100
Renaud Métrich <rmetrich@redhat.com> 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 disks or 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),
> which is done through using the following grub.cfg snippet:
> -------- 8< ---------------- 8< ---------------- 8< --------
> unset prefix
> search --file --set=prefix /EFI/redhat/grubx64.efi
> if [ -n "$prefix" ]; then
>   chainloader ($prefix)/EFI/redhat/grubx64/efi
> ...
> -------- 8< ---------------- 8< ---------------- 8< --------
> 
> With efi.quickboot, none of the devices are connected, causing "search"
> to fail. Sometimes devices are connected but not the partition of the
> disk matching $prefix, causing partition to not be found by
> "chainloader".
> 
> This patch introduces a new "connectefi pciroot|scsi" command which
> recursively connects all EFI devices starting from a given controller
> type:
> - if 'pciroot' is specified, recursion is performed for all PCI root
>   handles
> - if 'scsi' is specified, recursion is performed for all SCSI I/O
>   handles (recommended usage to avoid connecting unwanted handles which
>   may impact Grub performances)
> 
> Typical grub.cfg snippet would then be:
> -------- 8< ---------------- 8< ---------------- 8< --------
> connectefi scsi
> unset prefix
> search --file --set=prefix /EFI/redhat/grubx64.efi
> if [ -n "$prefix" ]; then
>   chainloader ($prefix)/EFI/redhat/grubx64/efi
> ...
> -------- 8< ---------------- 8< ---------------- 8< --------
> 
> The code is easily extensible to handle other arguments in the future if
> needed.
> 
> Signed-off-by: Renaud Métrich <rmetrich@redhat.com>
> ---
>  NEWS                                |   2 +-
>  grub-core/Makefile.core.def         |   6 +
>  grub-core/commands/efi/connectefi.c | 205 ++++++++++++++++++++++++++++
>  grub-core/commands/efi/lsefi.c      |   1 +
>  grub-core/disk/efi/efidisk.c        |  13 ++
>  grub-core/kern/efi/efi.c            |  13 ++
>  include/grub/efi/disk.h             |   2 +
>  include/grub/efi/efi.h              |   5 +
>  8 files changed, 246 insertions(+), 1 deletion(-)
>  create mode 100644 grub-core/commands/efi/connectefi.c
> 
> diff --git a/NEWS b/NEWS
> index 73b8492bc..d7c1d23ae 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -98,7 +98,7 @@ New in 2.02:
>    * Prefer pmtimer for TSC calibration.
>  
>  * New/improved platform support:
> -  * New `efifwsetup' and `lsefi' commands on EFI platforms.
> +  * New `efifwsetup', `lsefi' and `connectefi` commands on EFI platforms.
>    * New `cmosdump' and `cmosset' commands on platforms with CMOS support.
>    * New command `pcidump' for PCI platforms.
>    * Improve opcode parsing in ACPI halt implementation.
> diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
> index 8022e1c0a..196231be9 100644
> --- a/grub-core/Makefile.core.def
> +++ b/grub-core/Makefile.core.def
> @@ -808,6 +808,12 @@ module = {
>    enable = efi;
>  };
>  
> +module = {
> +  name = connectefi;
> +  common = commands/efi/connectefi.c;

I think this is better named as eficonnect.

> +  enable = efi;
> +};
> +
>  module = {
>    name = blocklist;
>    common = commands/blocklist.c;
> diff --git a/grub-core/commands/efi/connectefi.c 
> b/grub-core/commands/efi/connectefi.c
> new file mode 100644
> index 000000000..8ab75bd51
> --- /dev/null
> +++ b/grub-core/commands/efi/connectefi.c
> @@ -0,0 +1,205 @@
> +/*
> + *  GRUB  --  GRand Unified Bootloader
> + *  Copyright (C) 2022  Free Software Foundation, Inc.
> + *
> + *  GRUB is free software: you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation, either version 3 of the License, or
> + *  (at your option) any later version.
> + *
> + *  GRUB is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + *  You should have received a copy of the GNU General Public License
> + *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +#include <grub/types.h>
> +#include <grub/mm.h>
> +#include <grub/misc.h>
> +#include <grub/efi/api.h>
> +#include <grub/efi/pci.h>
> +#include <grub/efi/efi.h>
> +#include <grub/command.h>
> +#include <grub/err.h>
> +#include <grub/i18n.h>
> +
> +GRUB_MOD_LICENSE ("GPLv3+");
> +
> +typedef struct handle_list
> +{
> +  grub_efi_handle_t handle;
> +  struct handle_list *next;
> +} handle_list_t;

Why not use GRUB's existing list code? Its for a doubly linked list,
but I think the wasted memory will be small enough to not be a concern.
On the other hand, I'm not sure it buys much code reduction.

> +
> +static handle_list_t *already_handled = NULL;
> +
> +static grub_err_t
> +add_handle (grub_efi_handle_t handle)
> +{
> +  handle_list_t *e;
> +  e = grub_malloc (sizeof (*e));
> +  if (! e)
> +    return grub_errno;
> +  e->handle = handle;
> +  e->next = already_handled;
> +  already_handled = e;
> +  return GRUB_ERR_NONE;
> +}
> +
> +static int
> +is_in_list (grub_efi_handle_t handle)
> +{
> +  handle_list_t *e;
> +  for (e = already_handled; e != NULL; e = e->next)
> +    if (e->handle == handle)
> +      return 1;
> +  return 0;
> +}
> +
> +static void
> +free_handle_list (void)
> +{
> +  handle_list_t *e;
> +  while ((e = already_handled) != NULL)
> +    {
> +      already_handled = already_handled->next;
> +      grub_free (e);
> +    }
> +}
> +
> +typedef enum searched_item_flag
> +{
> +  SEARCHED_ITEM_FLAG_LOOP = 1,
> +  SEARCHED_ITEM_FLAG_RECURSIVE = 2
> +} searched_item_flags;
> +
> +typedef struct searched_item
> +{
> +  grub_efi_guid_t guid;
> +  const char *name;
> +  searched_item_flags flags;
> +} searched_items;
> +
> +static grub_err_t
> +grub_cmd_connectefi (grub_command_t cmd __attribute__ ((unused)),
> +                  int argc, char **args)
> +{
> +  unsigned s;
> +  searched_items pciroot_items[] =
> +    {
> +      { GRUB_EFI_PCI_ROOT_IO_GUID, "PCI root", SEARCHED_ITEM_FLAG_RECURSIVE }
> +    };
> +  searched_items scsi_items[] =
> +    {
> +      { GRUB_EFI_PCI_ROOT_IO_GUID, "PCI root", 0 },
> +      { GRUB_EFI_PCI_IO_GUID, "PCI", SEARCHED_ITEM_FLAG_LOOP },
> +      { GRUB_EFI_SCSI_IO_PROTOCOL_GUID, "SCSI I/O", 
> SEARCHED_ITEM_FLAG_RECURSIVE }
> +    };
> +  searched_items *items = NULL;
> +  unsigned nitems = 0;
> +  grub_err_t grub_err = GRUB_ERR_NONE;
> +  unsigned total_connected = 0;
> +
> +  if (argc != 1)
> +    return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("one argument expected"));
> +

I think it would be nice to support "all", which recursively connects
all handles. Its been discussed here how that can be problematic.
However, perhaps we should allow it, if its something requested by the
user explicitly.

> +  if (grub_strcmp(args[0], N_("pciroot")) == 0)

Do we really want to internationalize this? Would other languages really
want to have something different?

Glenn

> +    {
> +      items = pciroot_items;
> +      nitems = ARRAY_SIZE (pciroot_items);
> +    }
> +  else if (grub_strcmp(args[0], N_("scsi")) == 0)
> +    {
> +      items = scsi_items;
> +      nitems = ARRAY_SIZE (scsi_items);
> +    }
> +  else
> +    return grub_error (GRUB_ERR_BAD_ARGUMENT,
> +                    N_("unexpected argument `%s'"), args[0]);
> +
> +  for (s = 0; s < nitems; s++)
> +    {
> +      grub_efi_handle_t *handles;
> +      grub_efi_uintn_t num_handles;
> +      unsigned i, connected = 0, loop = 0;
> +
> +loop:
> +      loop++;
> +      grub_dprintf ("efi", "step '%s' loop %d:\n", items[s].name, loop);
> +
> +      handles = grub_efi_locate_handle (GRUB_EFI_BY_PROTOCOL,
> +                                     &items[s].guid, 0, &num_handles);
> +
> +      if (!handles)
> +     continue;
> +
> +      for (i = 0; i < num_handles; i++)
> +     {
> +       grub_efi_handle_t handle = handles[i];
> +       grub_efi_status_t status;
> +       unsigned j;
> +
> +       /* Skip already handled handles  */
> +       if (is_in_list (handle))
> +         {
> +           grub_dprintf ("efi", "  handle %p: already processed\n",
> +                                handle);
> +           continue;
> +         }
> +
> +       status = grub_efi_connect_controller(handle, NULL, NULL,
> +                     items[s].flags & SEARCHED_ITEM_FLAG_RECURSIVE ? 1 : 0);
> +       if (status == GRUB_EFI_SUCCESS)
> +         {
> +           connected++;
> +           total_connected++;
> +           grub_dprintf ("efi", "  handle %p: connected\n", handle);
> +         }
> +       else
> +         grub_dprintf ("efi", "  handle %p: failed to connect (%d)\n",
> +                              handle, (grub_efi_int8_t) status);
> +
> +       if ((grub_err = add_handle (handle)) != GRUB_ERR_NONE)
> +         break; /* fatal  */
> +     }
> +
> +      grub_free (handles);
> +      if (grub_err != GRUB_ERR_NONE)
> +     break; /* fatal  */
> +
> +      if (items[s].flags & SEARCHED_ITEM_FLAG_LOOP && connected)
> +     {
> +       connected = 0;
> +       goto loop;
> +     }
> +
> +      free_handle_list ();
> +    }
> +
> +  free_handle_list ();
> +
> +  if (total_connected)
> +    grub_efidisk_reenumerate_disks ();
> +
> +  return grub_err;
> +}
> +
> +static grub_command_t cmd;
> +
> +GRUB_MOD_INIT(connectefi)
> +{
> +  cmd = grub_register_command ("connectefi", grub_cmd_connectefi,
> +                            N_("pciroot|scsi"),
> +                            N_("Connect EFI handles."
> +                               " If 'pciroot' is specified, connect PCI"
> +                               " root EFI handles recursively."
> +                               " If 'scsi' is specified, connect SCSI"
> +                               " I/O EFI handles recursively."));
> +}
> +
> +GRUB_MOD_FINI(connectefi)
> +{
> +  grub_unregister_command (cmd);
> +}
> diff --git a/grub-core/commands/efi/lsefi.c b/grub-core/commands/efi/lsefi.c
> index b1f2d4695..7a35bd4f9 100644
> --- a/grub-core/commands/efi/lsefi.c
> +++ b/grub-core/commands/efi/lsefi.c
> @@ -19,6 +19,7 @@
>  #include <grub/mm.h>
>  #include <grub/misc.h>
>  #include <grub/efi/api.h>
> +#include <grub/efi/disk.h>
>  #include <grub/efi/edid.h>
>  #include <grub/efi/pci.h>
>  #include <grub/efi/efi.h>
> diff --git a/grub-core/disk/efi/efidisk.c b/grub-core/disk/efi/efidisk.c
> index f077b5f55..eb0de5625 100644
> --- a/grub-core/disk/efi/efidisk.c
> +++ b/grub-core/disk/efi/efidisk.c
> @@ -396,6 +396,19 @@ enumerate_disks (void)
>    free_devices (devices);
>  }
>  
> +void
> +grub_efidisk_reenumerate_disks (void)
> +{
> +  free_devices (fd_devices);
> +  free_devices (hd_devices);
> +  free_devices (cd_devices);
> +  fd_devices = 0;
> +  hd_devices = 0;
> +  cd_devices = 0;
> +
> +  enumerate_disks ();
> +}
> +
>  static int
>  grub_efidisk_iterate (grub_disk_dev_iterate_hook_t hook, void *hook_data,
>                     grub_disk_pull_t pull)
> 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/disk.h b/include/grub/efi/disk.h
> index 254475c84..6845c2f1f 100644
> --- a/include/grub/efi/disk.h
> +++ b/include/grub/efi/disk.h
> @@ -27,6 +27,8 @@ grub_efi_handle_t
>  EXPORT_FUNC(grub_efidisk_get_device_handle) (grub_disk_t disk);
>  char *EXPORT_FUNC(grub_efidisk_get_device_name) (grub_efi_handle_t *handle);
>  
> +void EXPORT_FUNC(grub_efidisk_reenumerate_disks) (void);
> +
>  void grub_efidisk_init (void);
>  void grub_efidisk_fini (void);
>  
> 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);