From: Paul Mackerras <paulus@ozlabs.org>
To: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: linuxppc-dev@lists.ozlabs.org, kvm-ppc@vger.kernel.org
Subject: Re: [PATCH kernel] KVM: PPC: Expose userspace mm context id via debugfs
Date: Tue, 17 Jul 2018 02:01:19 +0000 [thread overview]
Message-ID: <20180717020119.GA11424@fergus> (raw)
In-Reply-To: <20180712073026.19463-1-aik@ozlabs.ru>
On Thu, Jul 12, 2018 at 05:30:26PM +1000, Alexey Kardashevskiy wrote:
> This adds a debugfs entry with mm context id of a process which is using
> KVM. This id is an index in the process table so the userspace can dump
> that tree provided it is granted access to /dev/mem.
Is the main intention here to be able to look at the PTEs for the
process that owns the VM? If so, that doesn't seem particularly
KVM-specific, so perhaps something under powerpc/ in debugfs would be
more appropriate.
Is the information in /proc/<pid>/pagemap sufficient for what you
need?
Also, this doesn't seem very useful if /dev/mem is unavailable or
restricted, as it is in most distros these days.
How about a file under debugfs where you can just read out the PTEs
for a given process?
Paul.
WARNING: multiple messages have this Message-ID (diff)
From: Paul Mackerras <paulus@ozlabs.org>
To: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: linuxppc-dev@lists.ozlabs.org, kvm-ppc@vger.kernel.org
Subject: Re: [PATCH kernel] KVM: PPC: Expose userspace mm context id via debugfs
Date: Tue, 17 Jul 2018 12:01:19 +1000 [thread overview]
Message-ID: <20180717020119.GA11424@fergus> (raw)
In-Reply-To: <20180712073026.19463-1-aik@ozlabs.ru>
On Thu, Jul 12, 2018 at 05:30:26PM +1000, Alexey Kardashevskiy wrote:
> This adds a debugfs entry with mm context id of a process which is using
> KVM. This id is an index in the process table so the userspace can dump
> that tree provided it is granted access to /dev/mem.
Is the main intention here to be able to look at the PTEs for the
process that owns the VM? If so, that doesn't seem particularly
KVM-specific, so perhaps something under powerpc/ in debugfs would be
more appropriate.
Is the information in /proc/<pid>/pagemap sufficient for what you
need?
Also, this doesn't seem very useful if /dev/mem is unavailable or
restricted, as it is in most distros these days.
How about a file under debugfs where you can just read out the PTEs
for a given process?
Paul.
next prev parent reply other threads:[~2018-07-17 2:01 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-12 7:30 [PATCH kernel] KVM: PPC: Expose userspace mm context id via debugfs Alexey Kardashevskiy
2018-07-12 7:30 ` Alexey Kardashevskiy
2018-07-17 2:01 ` Paul Mackerras [this message]
2018-07-17 2:01 ` Paul Mackerras
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