From: "Valdis Klētnieks" <valdis.kletnieks@vt.edu>
To: Sahibzada Irfanullah <irfan.gomalian@gmail.com>
Cc: kernelnewbies@kernelnewbies.org
Subject: Re: Fwd: Need Help regarding Reading and Writting to a file from kernel function file
Date: Tue, 24 Sep 2019 04:48:59 -0400 [thread overview]
Message-ID: <233594.1569314939@turing-police> (raw)
In-Reply-To: <CAGaWEbr96h+Bi4qmP-1Wse+wk=r4Us3CeDY3AXO6xR+_QceNKw@mail.gmail.com>
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On Tue, 24 Sep 2019 16:10:07 +0900, Sahibzada Irfanullah said:
> subject line. The problem is: I am trying to write/read page faulted
> physical addresses to a file in a kernel (v5.3-1) function, i.e.,
> handle_ept_violation() which is present in vmx.c. I have followed this
> <https://stackoverflow.com/questions/1184274/read-write-files-within-a-linux-kernel-module>,
Just because somebody on stackoverflow gave a guide doesn't mean it's
a good idea.
What problem are you trying to solve here? Are you trying to write the faulted
pages themselves to a file? In that case, just creating the file, using something like
'dd if=/dev/zero of=/your/file/here bs=1M count=4096' and then using mkswap
and swapon will probably work much better.
If you're trying to produce a trace of what pages are being faulted, you can
probably do a better job by using 'perf' to produce trace events with a lot of
added data for you, or use debugfs or netlink and a userspace program to read
the data and write it to disk from userspace.
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next prev parent reply other threads:[~2019-09-24 8:51 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAGaWEbomboZ=MCT4GaKj+5tUNDGc5ZknvhLTikCPSWpjY5E7hA@mail.gmail.com>
2019-09-24 7:10 ` Fwd: Need Help regarding Reading and Writting to a file from kernel function file Sahibzada Irfanullah
2019-09-24 7:35 ` Greg KH
2019-09-24 8:48 ` Valdis Klētnieks [this message]
2019-09-24 9:51 ` Saket Sinha
2019-09-24 13:32 ` Greg KH
2019-09-24 10:02 ` Martin Christian
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