archive mirror
 help / color / mirror / Atom feed
From: "Jan Beulich" <>
To: "Juergen Gross" <>
Cc: <>, <>,
	<>, <>,
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: <> (raw)
In-Reply-To: <>

>>> Juergen Gross <> 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


  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]     ` <>
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

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:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \ \ \
    --subject='Re: [Xen-devel] [PATCH] xen: remove size limit of privcmd-buf mapping interface' \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

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).