memory: Do not allow direct write access to rom_device regions

According to the documentation in memory.h a ROM memory region will be
backed by RAM for reads, but is supposed to go through a callback for
writes. Currently we were not checking for the existence of the rom_device
flag when determining if we could perform a direct write or not.

To correct that add a check to memory_region_is_direct so that if the
memory region has the rom_device flag set we will return false for all
checks where is_write is set.

Backports commit d489ae4ac57ebe14bde8384556cbac237ead988d from qemu
This commit is contained in:
Alexander Duyck 2020-04-30 07:25:57 -04:00 committed by Lioncash
parent 7c32c5b0a4
commit 05cd02d6c6

View file

@ -1348,8 +1348,8 @@ void *qemu_map_ram_ptr(struct uc_struct *uc, RAMBlock *ram_block,
static inline bool memory_access_is_direct(MemoryRegion *mr, bool is_write)
{
if (is_write) {
return memory_region_is_ram(mr) &&
!mr->readonly && !memory_region_is_ram_device(mr);
return memory_region_is_ram(mr) && !mr->readonly &&
!mr->rom_device && !memory_region_is_ram_device(mr);
} else {
return (memory_region_is_ram(mr) && !memory_region_is_ram_device(mr)) ||
memory_region_is_romd(mr);