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From: "Jan Beulich" <jbeulich@suse.com>
To: "Juergen Gross" <jgross@suse.com>
Cc: <sstabellini@kernel.org>, <xen-devel@lists.xenproject.org>,
	<boris.ostrovsky@oracle.com>, <linux-kernel@vger.kernel.org>,
	<stable@vger.kernel.org>
Subject: Re: [Xen-devel] [PATCH] xen: remove size limit of privcmd-buf mapping interface
Date: Thu, 01 Nov 2018 08:18:12 -0600	[thread overview]
Message-ID: <5BDB0B240200007800142507@prv1-mh.provo.novell.com> (raw)
In-Reply-To: <20181101123307.8424-1-jgross@suse.com>

>>> Juergen Gross <jgross@suse.com> 11/01/18 1:34 PM >>>
>Currently the size of hypercall buffers allocated via
>/dev/xen/hypercall is limited to a default of 64 memory pages. For live
>migration of guests this might be too small as the page dirty bitmask
>needs to be sized according to the size of the guest. This means
>migrating a 8GB sized guest is already exhausting the default buffer
>size for the dirty bitmap.
>
>There is no sensible way to set a sane limit, so just remove it
>completely. The device node's usage is limited to root anyway, so there
>is no additional DOS scenario added by allowing unlimited buffers.

But is this setting of permissions what we want long term? What about a
de-privileged qemu, which still needs to be able to issue at least dm-op
hypercalls?

Jan



  reply	other threads:[~2018-11-01 14:18 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-01 12:33 Juergen Gross
2018-11-01 14:18 ` Jan Beulich [this message]
2018-11-01 14:23   ` [Xen-devel] " Juergen Gross
2018-11-01 15:50     ` Jan Beulich
     [not found]     ` <5BDB20AB020000780014251B@suse.com>
2018-11-01 16:27       ` Juergen Gross
2018-11-02  7:26         ` Jan Beulich
2018-11-01 14:23   ` Andrew Cooper
2018-11-09  7:03 ` Juergen Gross
2018-11-09 14:23   ` Boris Ostrovsky
2018-11-02  9:53 [Xen-devel] " Juergen Gross

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