On 6/17/20 3:06 PM, Alex Williamson wrote: > On Wed, 17 Jun 2020 16:39:56 +1000 > David Gibson <da...@gibson.dropbear.id.au> wrote: > >> On Wed, Jun 17, 2020 at 11:09:27AM +0530, P J P wrote: >>> From: Prasad J Pandit <p...@fedoraproject.org> >>> >>> Hello, >>> >>> This series adds various undefined MMIO read/write functions >>> to avoid potential guest crash via a NULL pointer dereference. >> >> Hrm. If this is such a common problem, maybe we should just add a >> NULL check in the common paths. > > +1, clearly the behavior is already expected. Thanks,
20 months ago Peter suggested: "assert that every MemoryRegionOps has pointers to callbacks in it, when it is registered in memory_region_init_io() and memory_region_init_rom_device_nomigrate()." https://www.mail-archive.com/qemu-devel@nongnu.org/msg573310.html Li Qiang refers to this post from Paolo: > static const MemoryRegionOps notdirty_mem_ops = { > + .read = notdirty_mem_read, > .write = notdirty_mem_write, > .valid.accepts = notdirty_mem_accepts, > .endianness = DEVICE_NATIVE_ENDIAN, "This cannot happen, since TLB_NOTDIRTY is only added to the addr_write member (see accel/tcg/cputlb.c)." https://www.mail-archive.com/qemu-devel@nongnu.org/msg561345.html