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Date: Fri, 14 Dec 2018 12:50:22 -0500
From: "Emilio G. Cota" <cota@braap.org>
Message-ID: <20181214175022.GA18314@flamenco>
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Subject: Re: [Qemu-devel] [RFC v2 05/38] plugin: add user-facing API
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To: Aaron Lindsay <aaron@os.amperecomputing.com>
Cc: Alex =?iso-8859-1?Q?Benn=E9e?= <alex.bennee@linaro.org>, Richard Henderson <richard.henderson@linaro.org>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>

On Fri, Dec 14, 2018 at 12:08:22 -0500, Emilio G. Cota wrote:
> On Fri, Dec 14, 2018 at 15:57:32 +0000, Aaron Lindsay wrote:
(snip)
> > I added a function to the user-facing plugin API in my own version of
> > Pavel's plugin patchset to clear all existing plugin instrumentation,
(snip)
> I think the following API call would do what you need:
> 
>   typedef int (*qemu_plugin_reset_cb_t)(qemu_plugin_id_t id);
>   void qemu_plugin_reset(qemu_plugin_id_t id, qemu_plugin_reset_cb_t cb);
> 
> (or maybe qemu_plugin_reinstall?)

An alternative is to track the TBs that a plugin has inserted
instrumentation into, and only flush those. This would require
us to do an additional hash table insert when adding a
direct callback, but it allow us to avoid exporting tb_flush indirectly
to plugins, which could be abused by malicious plugins to perform
a DoS attack.

I'll look into this.

		E.