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From: Paolo Bonzini <pbonzini@redhat.com>
To: "Daniel P. Berrange" <berrange@redhat.com>,
	Markus Armbruster <armbru@redhat.com>
Cc: kwolf@redhat.com, qemu-devel@nongnu.org,
	Luiz Capitulino <lcapitulino@redhat.com>
Subject: Re: [Qemu-devel] [RFC 2/3] QMP: rate limit BLOCK_IO_ERROR
Date: Sun, 17 Aug 2014 08:08:14 +0200	[thread overview]
Message-ID: <53F046CE.1000205@redhat.com> (raw)
In-Reply-To: <20140811111518.GQ11762@redhat.com>

Il 11/08/2014 13:15, Daniel P. Berrange ha scritto:
>> > 1. Don't throttle.  Client can rely on events as long as it keeps the
>> >    QMP connection alive.  Client should poll after establishing the QMP
>> >    connection.
> A malicious guest OS can flood libvirt with events in this way. Of course
> even if we throttle, a compromised QEMU can still flood libvirt. The only
> fail-safe protection is for libvirt to detect flooding and throttle the
> rate at which it talks to the (malicious) QEMU.
> 

If you use rerror=stop,werror=stop, only a limited error can be passed
down to libvirt before libvirt invokes the "cont" command and there's no
need to do any throttling.

Paolo

  reply	other threads:[~2014-08-17  6:08 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-23 13:17 [Qemu-devel] [RFC 0/3] QMP: extend BLOCK_IO_ERROR event Luiz Capitulino
2014-07-23 13:17 ` [Qemu-devel] [RFC 1/3] qapi: block-core.json: improve query-block doc Luiz Capitulino
2014-08-05 12:13   ` Eric Blake
2014-07-23 13:17 ` [Qemu-devel] [RFC 2/3] QMP: rate limit BLOCK_IO_ERROR Luiz Capitulino
2014-08-05 12:14   ` Eric Blake
2014-08-11  8:17   ` Daniel P. Berrange
2014-08-11 11:07     ` Markus Armbruster
2014-08-11 11:15       ` Daniel P. Berrange
2014-08-17  6:08         ` Paolo Bonzini [this message]
2014-08-14 13:13     ` Luiz Capitulino
2014-07-23 13:17 ` [Qemu-devel] [RFC 3/3] QMP: extend BLOCK_IO_ERROR event with no-space indicator Luiz Capitulino
2014-08-05 12:19   ` Eric Blake
2014-08-14 13:07     ` Luiz Capitulino
2014-08-05  9:13 ` [Qemu-devel] [RFC 0/3] QMP: extend BLOCK_IO_ERROR event Kevin Wolf
2014-08-14 13:05   ` Luiz Capitulino

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