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From: "Philippe Mathieu-Daudé" <philmd@redhat.com>
To: Alex Williamson <alex.williamson@redhat.com>,
	David Gibson <david@gibson.dropbear.id.au>
Cc: "Peter Maydell" <peter.maydell@linaro.org>,
	"Prasad J Pandit" <pjp@fedoraproject.org>,
	"Li Qiang" <liq3ea@163.com>, "Li Qiang" <liq3ea@gmail.com>,
	"QEMU Developers" <qemu-devel@nongnu.org>,
	"P J P" <ppandit@redhat.com>, "Lei Sun" <slei.casper@gmail.com>,
	"Hervé Poussineau" <hpoussin@reactos.org>,
	"Joel Stanley" <joel@jms.id.au>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Li Qiang" <pangpei.lq@antfin.com>
Subject: Re: [PATCH 0/6] Add various undefined MMIO r/w functions
Date: Wed, 17 Jun 2020 15:20:22 +0200	[thread overview]
Message-ID: <8357f8a5-83e3-47a7-57c9-b88edfa3812c@redhat.com> (raw)
In-Reply-To: <20200617070621.29051d4b@x1.home>

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



  reply	other threads:[~2020-06-17 13:21 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-17  5:39 [PATCH 0/6] Add various undefined MMIO r/w functions P J P
2020-06-17  5:39 ` [PATCH 1/6] hw/pci-host: add pci-intack write method P J P
2020-06-17  5:39 ` [PATCH 2/6] pci-host: add pcie-msi read method P J P
2020-06-17  5:39 ` [PATCH 3/6] vfio: add quirk device write method P J P
2020-06-17  7:33   ` Philippe Mathieu-Daudé
2020-06-17  5:39 ` [PATCH 4/6] prep: add ppc-parity " P J P
2020-06-17  7:47   ` Philippe Mathieu-Daudé
2020-06-17  5:39 ` [PATCH 5/6] nvram: add nrf51_soc flash read method P J P
2020-06-17  7:42   ` Philippe Mathieu-Daudé
2020-06-17  5:39 ` [PATCH 6/6] spapr_pci: add spapr msi " P J P
2020-06-17  7:45   ` Philippe Mathieu-Daudé
2020-06-17  6:07 ` [PATCH 0/6] Add various undefined MMIO r/w functions no-reply
2020-06-17  6:39 ` David Gibson
2020-06-17 13:06   ` Alex Williamson
2020-06-17 13:20     ` Philippe Mathieu-Daudé [this message]
2020-06-17 14:05       ` Alex Bennée
2020-06-17 14:42         ` Philippe Mathieu-Daudé
2020-06-17 15:08       ` Paolo Bonzini
2020-06-17 17:57         ` P J P

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