From: Spencer Michaels <sxmichaels@gmail.com>
To: Razvan Cojocaru <rcojocaru@bitdefender.com>
Cc: xen-devel@lists.xenproject.org
Subject: Re: Reading guest page flags
Date: Fri, 14 Sep 2018 01:01:33 -0700 [thread overview]
Message-ID: <CAMf-k8F6NFiPsm_ezQObZFQoVovW1Ot4_Q+G=ugoxz4zPYESSQ@mail.gmail.com> (raw)
In-Reply-To: <daf65b86-e750-5544-9c5b-fd7ecb977738@bitdefender.com>
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Thanks! Sorry, I should have been more specific - I do indeed mean the
regular guest PTEs (and I'm using PV guests which as I understand don't use
EPT anyway). So, it seems I'll have to write my own code for this. I'll
take a look at libvmi's implementation; if anyone knows any other libraries
/ programs that read guest PTEs, that would be helpful to know as well.
On Thu, Sep 13, 2018, 10:47 AM Razvan Cojocaru <rcojocaru@bitdefender.com>
wrote:
> On 9/13/18 8:29 PM, Spencer Michaels wrote:
> > I'm writing an application that can read/write guest memory, and as part
> > of that I need to check whether the page being manipulated is
> > readable/writable by the guest itself. Does Xen have an API that would
> > allow me to read the flags of an arbitrary page on a guest, given either
> > its address or its PFN? I've only been able to find functions that
> > update the existing memory mappings, but none to read them.
>
> If you mean EPT, yes: look at xc_get_mem_access() in xenctrl.h / libxc.
> If you mean "regular" PTEs, no - you'd have to write your own code to
> retrieve that.
>
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prev parent reply other threads:[~2018-09-14 8:01 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-13 17:29 Reading guest page flags Spencer Michaels
2018-09-13 17:47 ` Razvan Cojocaru
2018-09-13 18:45 ` Tamas K Lengyel
2018-09-14 8:01 ` Spencer Michaels [this message]
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