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Re: [PATCH 0/6] Add various undefined MMIO r/w functions
From: |
Philippe Mathieu-Daudé |
Subject: |
Re: [PATCH 0/6] Add various undefined MMIO r/w functions |
Date: |
Wed, 17 Jun 2020 15:20:22 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 |
On 6/17/20 3:06 PM, Alex Williamson wrote:
> On Wed, 17 Jun 2020 16:39:56 +1000
> David Gibson <david@gibson.dropbear.id.au> wrote:
>
>> On Wed, Jun 17, 2020 at 11:09:27AM +0530, P J P wrote:
>>> From: Prasad J Pandit <pjp@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
- Re: [PATCH 3/6] vfio: add quirk device write method, (continued)
- [PATCH 4/6] prep: add ppc-parity write method, P J P, 2020/06/17
- [PATCH 5/6] nvram: add nrf51_soc flash read method, P J P, 2020/06/17
- [PATCH 6/6] spapr_pci: add spapr msi read method, P J P, 2020/06/17
- Re: [PATCH 0/6] Add various undefined MMIO r/w functions, no-reply, 2020/06/17
- Re: [PATCH 0/6] Add various undefined MMIO r/w functions, David Gibson, 2020/06/17