[PATCH v3 6/6] efi: mm: Implement runtime addition of pages

[Patrick Steinhardt]

Adjust the interface of `grub_efi_mm_add_regions ()` to take a set of
`GRUB_MM_ADD_REGION_*` flags, which most notably is currently only the
`CONSECUTVE` flag. This allows us to set the function up as callback for
the memory subsystem and have it call out to us in case there's not
enough pages available in the current heap.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
---
 grub-core/kern/efi/mm.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/grub-core/kern/efi/mm.c b/grub-core/kern/efi/mm.c
index ced3ee5e7..f3d2e2b99 100644
--- a/grub-core/kern/efi/mm.c
+++ b/grub-core/kern/efi/mm.c
@@ -482,7 +482,8 @@ static grub_err_t
 add_memory_regions (grub_efi_memory_descriptor_t *memory_map,
                    grub_efi_uintn_t desc_size,
                    grub_efi_memory_descriptor_t *memory_map_end,
-                   grub_efi_uint64_t required_pages)
+                   grub_efi_uint64_t required_pages,
+                   unsigned int flags)
 {
   grub_efi_memory_descriptor_t *desc;
 
@@ -496,6 +497,10 @@ add_memory_regions (grub_efi_memory_descriptor_t 
*memory_map,
 
       start = desc->physical_start;
       pages = desc->num_pages;
+
+      if (pages < required_pages && (flags & GRUB_MM_ADD_REGION_CONSECUTIVE))
+       continue;
+
       if (pages > required_pages)
        {
          start += PAGES_TO_BYTES (pages - required_pages);
@@ -559,7 +564,7 @@ print_memory_map (grub_efi_memory_descriptor_t *memory_map,
 #endif
 
 static grub_err_t
-grub_efi_mm_add_regions (grub_efi_uint64_t required_bytes)
+grub_efi_mm_add_regions (grub_efi_uint64_t required_bytes, unsigned int flags)
 {
   grub_efi_memory_descriptor_t *memory_map;
   grub_efi_memory_descriptor_t *memory_map_end;
@@ -614,7 +619,8 @@ grub_efi_mm_add_regions (grub_efi_uint64_t required_bytes)
   /* Allocate memory regions for GRUB's memory management.  */
   err = add_memory_regions (filtered_memory_map, desc_size,
                            filtered_memory_map_end,
-                           BYTES_TO_PAGES (required_bytes));
+                           BYTES_TO_PAGES (required_bytes),
+                           flags);
   if (err != GRUB_ERR_NONE)
     return err;
 
@@ -641,8 +647,9 @@ grub_efi_mm_add_regions (grub_efi_uint64_t required_bytes)
 void
 grub_efi_mm_init (void)
 {
-  if (grub_efi_mm_add_regions (DEFAULT_HEAP_SIZE) != GRUB_ERR_NONE)
+  if (grub_efi_mm_add_regions (DEFAULT_HEAP_SIZE, GRUB_MM_ADD_REGION_NONE) != 
GRUB_ERR_NONE)
     grub_fatal ("%s", grub_errmsg);
+  grub_mm_add_region_fn = grub_efi_mm_add_regions;
 }
 
 #if defined (__aarch64__) || defined (__arm__) || defined (__riscv)
-- 
2.32.0

signature.asc
Description: PGP signature