From: "Roger Pau Monné" <roger.pau@citrix.com>
To: Juergen Gross <jgross@suse.com>
Cc: <xen-devel@lists.xenproject.org>,
Ian Jackson <iwj@xenproject.org>, Wei Liu <wl@xen.org>,
Julien Grall <julien@xen.org>
Subject: Re: [PATCH DNA 5/6] tools/xenstored: restore support for mapping ring as foreign memory
Date: Mon, 20 Sep 2021 12:42:06 +0200 [thread overview]
Message-ID: <YUhlfuPWEqnT0/42@MacBook-Air-de-Roger.local> (raw)
In-Reply-To: <b1fb5e04-29a8-c60b-c754-5a4275a0601e@suse.com>
On Mon, Sep 20, 2021 at 10:24:45AM +0200, Juergen Gross wrote:
> On 17.09.21 17:46, Roger Pau Monne wrote:
> > Restore the previous way of mapping the xenstore ring using foreign
> > memory. Use xenforeignmemory instead of libxc in order to avoid adding
> > another dependency on a unstable interface.
>
> Mapping a guest page via xenforeignmemory is no good move IMO. A guest
> not supporting a grant table for security reasons is a rather strange
> idea, as it needs to trade that for a general memory access by any
> backend without a way to restrict such accesses. This contradicts one
> of the main concepts of the Xen security architecture.
I've done this in order to be able to assert that the switch to
disable grant tables was working correctly, I don't intended this
specific mode to be something that is desirable or that should be used
in production, but I do think it's useful to be able to create such
guests in order to assert that the option is taking effect.
The main problem of xenstore not being correctly initialized on a
domain is that the "@introduceDomain" watch doesn't fire, and thus
other components don't get notified of the newly created domain.
This seems to be a limitation of the current design, where the only
way to get notifications of new domain creation is using
"@introduceDomain", even when the caller doesn't care of whether the
created domain as a working xenstore connection.
Maybe I can workaround this differently in xenstore, so that the watch
fires even when the shared xenstore ring cannot be initialized.
Thanks, Roger.
next prev parent reply other threads:[~2021-09-20 10:42 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-17 15:46 [PATCH 0/6] gnttab: add per-domain controls Roger Pau Monne
2021-09-17 15:46 ` [PATCH 1/6] gnttab: allow setting max version per-domain Roger Pau Monne
2021-09-17 15:46 ` [PATCH 2/6] gnttab: allow per-domain control over transitive grants Roger Pau Monne
2021-09-20 9:32 ` Andrew Cooper
2021-09-20 11:45 ` Roger Pau Monné
2021-09-17 15:46 ` [PATCH 3/6] tools/console: use xenforeigmemory to map console ring Roger Pau Monne
2021-09-20 10:32 ` Ian Jackson
2021-09-17 15:46 ` [PATCH 4/6] tools/xenstored: use atexit to close interfaces Roger Pau Monne
2021-09-20 7:17 ` Roger Pau Monné
2021-09-20 9:22 ` Juergen Gross
2021-09-20 10:53 ` Roger Pau Monné
2021-09-20 10:57 ` Ian Jackson
2021-09-20 11:02 ` Juergen Gross
2021-09-20 12:21 ` Ian Jackson
2021-09-20 10:34 ` Ian Jackson
2021-09-20 10:39 ` Juergen Gross
2021-09-17 15:46 ` [PATCH DNA 5/6] tools/xenstored: restore support for mapping ring as foreign memory Roger Pau Monne
2021-09-20 8:24 ` Juergen Gross
2021-09-20 10:42 ` Roger Pau Monné [this message]
2021-09-20 10:51 ` Juergen Gross
2021-09-20 10:35 ` Ian Jackson
2021-09-17 15:46 ` [PATCH 6/6] gnttab: allow disabling grant table per-domain Roger Pau Monne
2021-09-17 16:06 ` [PATCH 0/6] gnttab: add per-domain controls Christian Lindig
2021-09-20 7:26 ` Roger Pau Monné
2021-09-20 8:24 ` Edwin Torok
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