newbie question: memory sharing between Kernel-user mode

NTDEV
2

There is no entirely squeaky-clean way to map the physical pages
described by kernel memory into the address of a user-mode process
(which will save you a memory copy), but if you want to take a shot at
it check out the OSR article linked below. The other direction
(user->kernel) is highly optimized, just not the reverse commute. :slight_smile:

  • Nick Ryan

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of sxw
Sent: Tuesday, June 10, 2003 11:15 PM
To: NT Developers Interest List
Subject: [ntdev] newbie question: memory sharing between Kernel-user
mode

Hi,

My kernel mode driver receive buffer during IRP_MJ_READ/WRITE, and this
buffer is needed to be transfered to an user mode process to do some
checks, can I transfer the buffer pointer(or MDL) directly back to that
user mode process?

If it can't work, the only way I know at this time is to allocate a new
buffer in kernel mode and do copies and then transfer the handle of
that section to user mode, it looks a little stupid , right?

Thanks

-sxw

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3

Thanks, Nick.

That article is very helpful, but there’s no current process context
available for my case, I’m not sure whether the ReadProcessMemory and
WriteProcessMemory work for this case. Because I have no more time left on
this problem, I’ll use an additional buffer for that.

-sxw

“Nick Ryan” ???:xxxxx@ntdev…
>
> There is no entirely squeaky-clean way to map the physical pages
> described by kernel memory into the address of a user-mode process
> (which will save you a memory copy), but if you want to take a shot at
> it check out the OSR article linked below. The other direction
> (user->kernel) is highly optimized, just not the reverse commute. :slight_smile:
>
> http://www.osronline.com/article.cfm?id=39
>
> - Nick Ryan
>
> -----Original Message-----
> From: xxxxx@lists.osr.com
> [mailto:xxxxx@lists.osr.com] On Behalf Of sxw
> Sent: Tuesday, June 10, 2003 11:15 PM
> To: NT Developers Interest List
> Subject: [ntdev] newbie question: memory sharing between Kernel-user
> mode
>
>
> Hi,
>
> My kernel mode driver receive buffer during IRP_MJ_READ/WRITE, and this
> buffer is needed to be transfered to an user mode process to do some
> checks, can I transfer the buffer pointer(or MDL) directly back to that
> user mode process?
>
> If it can’t work, the only way I know at this time is to allocate a new
> buffer in kernel mode and do copies and then transfer the handle of
> that section to user mode, it looks a little stupid , right?
>
> Thanks
>
> -sxw
>
> —
> You are currently subscribed to ntdev as: xxxxx@nryan.com
> To unsubscribe send a blank email to xxxxx@lists.osr.com
> —
> You are currently subscribed to ntdev as: xxxxx@nryan.com
> To unsubscribe send a blank email to xxxxx@lists.osr.com
>
>
>
>