x86/efi: Round EFI memmap reservations to EFI_PAGE_SIZE

Mike Galbraith reported that his machine started rebooting during boot
after,

  commit 8e80632fb2 ("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
EFI_PAGE_SIZE, nor is the start address on an EFI_PAGE_SIZE boundary.

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, and start addresses downwards, 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@gmail.com>
Reported-by: Mike Krinkin <krinkin.m.u@gmail.com>
Tested-by: Mike Krinkin <krinkin.m.u@gmail.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>

arch/x86/platform/efi/quirks.c

@@ -201,8 +201,12 @@ void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)
 		return;
 	}
 
+	size += addr % EFI_PAGE_SIZE;
+	size = round_up(size, EFI_PAGE_SIZE);
+	addr = round_down(addr, 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);