[PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into boot mem areas

Dave Young
2017-01-12T09:44:14Z

[-- Attachment #1: efi-memmap-insert-fix.patch --]
[-- Type: text/plain, Size: 3954 bytes --]

There are memory ranges like below when I testing early efi_mem_reserve:

efi: mem62: [Reserved | | | | | | | | | | | | ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
efi: mem63: [Reserved | | | | | | | | | | | | ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
efi: mem64: [Reserved | | | | | | | | | | | | ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
efi: mem65: [Reserved | | | | | | | | | | | | ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
efi: mem66: [Reserved | | | | | | | | | | | | ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
efi: mem67: [Reserved | | | | | | | | | | | | ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)

So efi_memmap_insert will run into inserting same region multiple times,
also because efi_memmap_insert does not consider the duplicate ranges it will
cause memmap buffer overflow due to the size is pre-calculated, and kernel boot
fail with a panic. We did not detect such issue because current users of
efi_mem_insert do it very late after switching to virtual mode, at that time
the new cooked efi.memmap contains only runtime needed memory ranges.

efi_mem_reserve cares only about boot services regions and maybe loader areas.
So add a new argument to efi_memmap_insert for this purpose.

Later patches depend on this one for moving bgrt reservation to early code.

Signed-off-by: Dave Young <dyoung@redhat.com>
---
arch/x86/platform/efi/quirks.c | 2 +-
drivers/firmware/efi/fake_mem.c | 3 ++-
drivers/firmware/efi/memmap.c | 8 +++++++-
include/linux/efi.h | 4 ++--
4 files changed, 12 insertions(+), 5 deletions(-)

--- linux-x86.orig/drivers/firmware/efi/memmap.c
+++ linux-x86/drivers/firmware/efi/memmap.c
@@ -213,7 +213,7 @@ int __init efi_memmap_split_count(efi_me
* to see how large @buf needs to be.
*/
void __init efi_memmap_insert(struct efi_memory_map *old_memmap, void *buf,
- struct efi_mem_range *mem)
+ struct efi_mem_range *mem, bool boot_only)
{
u64 m_start, m_end, m_attr;
efi_memory_desc_t *md;
@@ -246,6 +246,12 @@ void __init efi_memmap_insert(struct efi
start = md->phys_addr;
end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT) - 1;

+ if (boot_only && !(md->type == EFI_LOADER_DATA ||
+ md->type == EFI_LOADER_CODE ||
+ md->type == EFI_BOOT_SERVICES_CODE ||
+ md->type == EFI_BOOT_SERVICES_DATA))
+ continue;
+
if (m_start <= start && end <= m_end)
md->attribute |= m_attr;

--- linux-x86.orig/arch/x86/platform/efi/quirks.c
+++ linux-x86/arch/x86/platform/efi/quirks.c
@@ -226,7 +226,7 @@ void __init efi_arch_mem_reserve(phys_ad
return;
}

- efi_memmap_insert(&efi.memmap, new, &mr);
+ efi_memmap_insert(&efi.memmap, new, &mr, true);
early_memunmap(new, new_size);

efi_memmap_install(new_phys, num_entries);
--- linux-x86.orig/drivers/firmware/efi/fake_mem.c
+++ linux-x86/drivers/firmware/efi/fake_mem.c
@@ -85,7 +85,8 @@ void __init efi_fake_memmap(void)
}

for (i = 0; i < nr_fake_mem; i++)
- efi_memmap_insert(&efi.memmap, new_memmap, &fake_mems[i]);
+ efi_memmap_insert(&efi.memmap, new_memmap, &fake_mems[i],
+ false);

/* swap into new EFI memmap */
early_memunmap(new_memmap, efi.memmap.desc_size * new_nr_map);
--- linux-x86.orig/include/linux/efi.h
+++ linux-x86/include/linux/efi.h
@@ -957,8 +957,8 @@ extern int __init efi_memmap_install(phy
extern int __init efi_memmap_split_count(efi_memory_desc_t *md,
struct range *range);
extern void __init efi_memmap_insert(struct efi_memory_map *old_memmap,
- void *buf, struct efi_mem_range *mem);
-
+ void *buf, struct efi_mem_range *mem,
+ bool boot_only);
extern int efi_config_init(efi_config_table_type_t *arch_tables);
#ifdef CONFIG_EFI_ESRT
extern void __init efi_esrt_init(void);