efi: new 'eficonnect' command

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 "eficonnect pciroot|scsi|all" command whic
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)
- if 'all' is specified, recursion is performed on all handles (not
  recommended since it may heavily impact Grub performances)

Typical grub.cfg snippet would then be:
-------- 8< ---------------- 8< ---------------- 8< --------
eficonnect 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

@@ -12,6 +12,9 @@ New in 2.06:
 * BootHole and BootHole2 fixes.
 * ...and tons of other fixes and cleanups...
 
+* New/improved platform support:
+  * New `eficonnect' command on EFI platforms.
+
 New in 2.04:
 
 * GCC 8 and 9 support.
@@ -98,7 +101,7 @@ New in 2.02:
   * Prefer pmtimer for TSC calibration.
 
 * New/improved platform support:
-  * New `efifwsetup' and `lsefi' commands on EFI platforms.
+  * New `efifwsetup', `lsefi' 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.

grub-core/Makefile.core.def

@@ -833,6 +833,12 @@ module = {
   enable = efi;
 };
 
+module = {
+  name = eficonnect;
+  efi = commands/efi/eficonnect.c;
+  enable = efi;
+};
+
 module = {
   name = blocklist;
   common = commands/blocklist.c;

grub-core/commands/efi/eficonnect.c

@@ -0,0 +1,211 @@
+/*
+ *  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+");
+
+struct grub_efi_already_handled
+{
+  struct grub_efi_already_handled *next;
+  struct grub_efi_already_handled **prev;
+  grub_efi_handle_t handle;
+};
+
+static struct grub_efi_already_handled *already_handled;
+
+static struct grub_efi_already_handled *
+is_in_list (grub_efi_handle_t handle)
+{
+  struct grub_efi_already_handled *e;
+
+  FOR_LIST_ELEMENTS (e, already_handled)
+    if (e->handle == handle)
+      return e;
+
+  return NULL;
+}
+
+static void
+free_handle_list (void)
+{
+  struct grub_efi_already_handled *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_eficonnect (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"));
+
+  if (grub_strcmp(args[0], "pciroot") == 0)
+    {
+      items = pciroot_items;
+      nitems = ARRAY_SIZE (pciroot_items);
+    }
+  else if (grub_strcmp(args[0], "scsi") == 0)
+    {
+      items = scsi_items;
+      nitems = ARRAY_SIZE (scsi_items);
+    }
+  else if (grub_strcmp(args[0], N_("all")) == 0)
+    {
+      items = NULL;
+      nitems = 1;
+    }
+  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++;
+      if (items != NULL)
+	{
+	  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);
+	}
+      else
+	handles = grub_efi_locate_handle (GRUB_EFI_ALL_HANDLES,
+					  NULL, NULL, &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) != NULL)
+	    {
+	      grub_dprintf ("efi", "  handle %p: already processed\n",
+				   handle);
+	      continue;
+	    }
+
+	  status = grub_efi_connect_controller(handle, NULL, NULL,
+			!items || 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);
+
+	  struct grub_efi_already_handled *item = grub_malloc(sizeof (*item));
+	  if (!item)
+	    break; /* fatal  */
+	  grub_list_push (GRUB_AS_LIST_P (&already_handled), GRUB_AS_LIST (item));
+	  item->handle = handle;
+	}
+
+      grub_free (handles);
+      if (grub_err != GRUB_ERR_NONE)
+	break; /* fatal  */
+
+      if (items && 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(eficonnect)
+{
+  cmd = grub_register_command ("eficonnect", grub_cmd_eficonnect,
+			       /* TRANSLATORS: only translate 'all' keyword */
+			       N_("pciroot|scsi|all"),
+			       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."
+				  " If 'all' is specified, connect all"
+				  " EFI handles recursively."));
+}
+
+GRUB_MOD_FINI(eficonnect)
+{
+  grub_unregister_command (cmd);
+}

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>

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)

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,

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);
 

include/grub/efi/efi.h

@@ -41,6 +41,11 @@ 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);