From: "Jan Beulich" <JBeulich@suse.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Xen-devel <xen-devel@lists.xen.org>
Subject: Re: [PATCH] xen/x86: Remap text/data/bss with appropriate permissions
Date: Thu, 17 Mar 2016 09:32:58 -0600 [thread overview]
Message-ID: <56EADC3A02000078000DDF75@prv-mh.provo.novell.com> (raw)
In-Reply-To: <56EAC2E4.7040303@citrix.com>
>>> On 17.03.16 at 15:44, <andrew.cooper3@citrix.com> wrote:
> On 17/03/16 14:31, Jan Beulich wrote:
>> Also - do we really want to make this code dependent on
>> map_pages_to_xen() not intermediately zapping the mappings
>> being changed?
>
> Do you mean "immediately"?
No.
> As far as I can tell, it is guaranteed to be safe, even when remapping
> the code section. Updates to the live pagetables are using atomic
> writes, and I didn't spot a point which would end up with a transient
> non-present mapping.
But we may, at some point and for whatever reason, come to make
the function zap the mapping (i.e. clear the present bit), flush, and
only the re-establish the new mapping.
Jan
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
next prev parent reply other threads:[~2016-03-17 15:32 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-17 12:43 [PATCH] xen/x86: Remap text/data/bss with appropriate permissions Andrew Cooper
2016-03-17 12:43 ` [PATCH] DO NOT APPLY - debug keys for inspecting Xen mappings Andrew Cooper
2016-03-17 14:31 ` [PATCH] xen/x86: Remap text/data/bss with appropriate permissions Jan Beulich
2016-03-17 14:44 ` Andrew Cooper
2016-03-17 15:32 ` Jan Beulich [this message]
2016-03-17 16:15 ` Andrew Cooper
2016-03-18 7:25 ` Jan Beulich
2016-03-18 19:49 ` [PATCH v2] " Andrew Cooper
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=56EADC3A02000078000DDF75@prv-mh.provo.novell.com \
--to=jbeulich@suse.com \
--cc=andrew.cooper3@citrix.com \
--cc=xen-devel@lists.xen.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).