[PATCH] x86/efi: Round EFI memmap reservations to EFI_PAGE_SIZE

From: Matt Fleming
Date: Fri Sep 16 2016 - 10:12:47 EST

Mike reported that his machine started rebooting during boot after,

commit 8e80632fb23f ("efi/esrt: Use efi_mem_reserve() and avoid a kmalloc()")

The ESRT table on his machine is 56 bytes and at no point in the
efi_arch_mem_reserve() call path is that size rounded up to

Since the EFI memory map only deals with whole pages, inserting an EFI
memory region with 56 bytes results in a new entry covering zero
pages, and completely screws up the calculations for the old regions
that were trimmed.

Round all sizes upwards to the nearest EFI_PAGE_SIZE boundary.

Additionally, efi_memmap_insert() expects the mem::range::end value to
be one less than the end address for the region.

Reported-by: Mike Galbraith <umgwanakikbuti@xxxxxxxxx>
Cc: Peter Jones <pjones@xxxxxxxxxx>
Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Signed-off-by: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
arch/x86/platform/efi/quirks.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index f14b7a9da24b..e881b4b2ffd6 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -201,8 +201,10 @@ void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)

+ size = round_up(size, EFI_PAGE_SIZE);
mr.range.start = addr;
- mr.range.end = addr + size;
+ mr.range.end = addr + size - 1;
mr.attribute = md.attribute | EFI_MEMORY_RUNTIME;

num_entries = efi_memmap_split_count(&md, &mr.range);