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Re: [Qemu-devel] [PATCH 0/8] Add missed read callback for some memory re
From: |
Li Qiang |
Subject: |
Re: [Qemu-devel] [PATCH 0/8] Add missed read callback for some memory region |
Date: |
Thu, 13 Sep 2018 09:41:33 +0800 |
Philippe Mathieu-Daudé <address@hidden> 于2018年9月13日周四 上午1:12写道:
> Hi Li,
>
> On 9/12/18 6:01 PM, Li Qiang wrote:
> > From: Li Qiang <address@hidden>
> >
> > This patch set try to add the missed read callback for memory region.
> > Without this patchset, when the guest reads the IO port/memory, it will
> > cause an NULL-dereference issue. For example, add
> > "-device isa-debug-exit" to command, then read the 0x501 port, it causes
> a
> > SIGSEGV.
> >
> > The only exception is 'readonly_mem_ops' as its read is directly
> > access the underlying host ram as the comments says.
> >
> > These missed read callback is mostly pointed by Laszlo Ersek.
> >
> >
> >
> > Li Qiang (8):
> > fw_cfg_mem: add read memory region callback
> > hw: debugexit: add read callback
> > hw: hyperv_testdev: add read callback
> > hw: pc-testdev: add read memory region callback
> > hw: designware: add read memory region callback
> > hw: pvrdma: add read memory region callback
> > hw: sun4c: add read memory region callback
> > exec: add read callback for notdirty memory region
>
> Why not rather simply add a check in
> memory_region_oldmmio_read_accessor() instead?
>
> Eventually:
>
> {
> uint64_t tmp;
> int idx = ctz32(size);
>
> if (unlikely(mr->ops->old_mmio.write[idx]
> && !mr->ops->old_mmio.read[idx])) {
> tmp = 0; /* XXX is 0 the expected value??? */
> } else {
> tmp = mr->ops->old_mmio.read[idx](mr->opaque, addr);
> }
> ...
>
Hi, I have sent this patch. But...
We have discussed in another thread:
-->https://lists.gnu.org/archive/html/qemu-devel/2018-09/msg01391.html
Thanks,
Li Qiang
- [Qemu-devel] [PATCH 3/8] hw: hyperv_testdev: add read callback, (continued)
- [Qemu-devel] [PATCH 3/8] hw: hyperv_testdev: add read callback, Li Qiang, 2018/09/12
- [Qemu-devel] [PATCH 5/8] hw: designware: add read memory region callback, Li Qiang, 2018/09/12
- [Qemu-devel] [PATCH 6/8] hw: pvrdma: add read memory region callback, Li Qiang, 2018/09/12
- [Qemu-devel] [PATCH 8/8] exec: add read callback for notdirty memory region, Li Qiang, 2018/09/12
- [Qemu-devel] [PATCH 7/8] hw: sun4c: add read memory region callback, Li Qiang, 2018/09/12
- Re: [Qemu-devel] [PATCH 0/8] Add missed read callback for some memory region, Philippe Mathieu-Daudé, 2018/09/12
- Re: [Qemu-devel] [PATCH 0/8] Add missed read callback for some memory region,
Li Qiang <=