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memory: Do not allow direct write access to rom_device regions

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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.

Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Message-Id: <20200410034150.24738.98143.stgit@localhost.localdomain>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Alexander Duyck 2020-04-09 20:41:50 -07:00 committed by Paolo Bonzini
parent 1148e4f4dc
commit d489ae4ac5
1 changed files with 2 additions and 2 deletions
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4
include/exec/memory.h
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@ -2351,8 +2351,8 @@ void address_space_write_cached_slow(MemoryRegionCache *cache,
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);