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Re: [PATCH v2 9/9] memory: assert MemoryRegionOps callbacks are defined
From: |
Li Qiang |
Subject: |
Re: [PATCH v2 9/9] memory: assert MemoryRegionOps callbacks are defined |
Date: |
Mon, 29 Jun 2020 19:28:44 +0800 |
P J P <ppandit@redhat.com> 于2020年6月25日周四 上午3:00写道:
>
> From: Prasad J Pandit <pjp@fedoraproject.org>
>
> When registering a MemoryRegionOps object, assert that its
> read/write callback methods are defined. This avoids potential
> guest crash via a NULL pointer dereference.
>
> Suggested-by: Peter Maydell <peter.maydell@linaro.org>
> Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
> ---
> memory.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> Update v2: assert read/write_with_attrs methods
> -> https://lists.gnu.org/archive/html/qemu-devel/2020-06/msg05717.html
>
> diff --git a/memory.c b/memory.c
> index 2f15a4b250..3d635a1bca 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -1496,7 +1496,13 @@ void memory_region_init_io(MemoryRegion *mr,
> uint64_t size)
> {
> memory_region_init(mr, owner, name, size);
> - mr->ops = ops ? ops : &unassigned_mem_ops;
> + if (ops) {
> + assert(ops->read || ops->read_with_attrs);
> + assert(ops->write || ops->write_with_attrs);
> + mr->ops = ops;
> + } else {
> + mr->ops = &unassigned_mem_ops;
> + }
> mr->opaque = opaque;
> mr->terminates = true;
> }
> @@ -1674,6 +1680,8 @@ void
> memory_region_init_rom_device_nomigrate(MemoryRegion *mr,
> {
> Error *err = NULL;
> assert(ops);
> + assert(ops->read || ops->read_with_attrs);
Though here is not 100% right as the ROM device can has no read callback.
However the device can change between ROMD mode or MMIO mode.
So I think it's ok the developer can provide a null read callback even if they
don't need it.
Reviewed-by: Li Qiang <liq3ea@gmail.com>
> + assert(ops->write || ops->write_with_attrs);
> memory_region_init(mr, owner, name, size);
> mr->ops = ops;
> mr->opaque = opaque;
> --
> 2.26.2
>
- [PATCH v2 0/9] memory: assert and define MemoryRegionOps callbacks, P J P, 2020/06/24
- [PATCH v2 1/9] hw/pci-host: add pci-intack write method, P J P, 2020/06/24
- [PATCH v2 3/9] vfio: add quirk device write method, P J P, 2020/06/24
- [PATCH v2 2/9] pci-host: add pcie-msi read method, P J P, 2020/06/24
- [PATCH v2 9/9] memory: assert MemoryRegionOps callbacks are defined, P J P, 2020/06/24
- Re: [PATCH v2 9/9] memory: assert MemoryRegionOps callbacks are defined,
Li Qiang <=
- [PATCH v2 7/9] tz-ppc: add dummy read/write methods, P J P, 2020/06/24
[PATCH v2 4/9] prep: add ppc-parity write method, P J P, 2020/06/24