jcs.org / qemu
qemu with hax to log dma reads & writes jcs.org/2018/11/12/vfio
fork atom

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.

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>

authored by

Alexander Duyck and committed by
Paolo Bonzini d489ae4a 1148e4f4

+2 -2
+2 -2
include/exec/memory.h
··· 2351 2351 static inline bool memory_access_is_direct(MemoryRegion *mr, bool is_write) 2352 2352 { 2353 2353 if (is_write) { 2354 - return memory_region_is_ram(mr) && 2355 - !mr->readonly && !memory_region_is_ram_device(mr); 2354 + return memory_region_is_ram(mr) && !mr->readonly && 2355 + !mr->rom_device && !memory_region_is_ram_device(mr); 2356 2356 } else { 2357 2357 return (memory_region_is_ram(mr) && !memory_region_is_ram_device(mr)) || 2358 2358 memory_region_is_romd(mr);