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From: "Jan Beulich" <JBeulich@suse.com>
To: Wei Liu <wei.liu2@citrix.com>
Cc: Martin Pohlack <mpohlack@amazon.de>,
	Julien Grall <julien.grall@arm.com>,
	Joao Martins <joao.m.martins@oracle.com>,
	Stefano Stabellini <sstabellini@kernel.org>,
	Mihai Dontu <mdontu@bitdefender.com>,
	Marek Marczykowski <marmarek@invisiblethingslab.com>,
	Anthony Liguori <aliguori@amazon.com>,
	uwed@amazon.de, Lars Kurth <lars.kurth@citrix.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	Ross Philipson <ross.philipson@oracle.com>,
	george.dunlap@citrix.com, Dario Faggioli <dfaggioli@suse.com>,
	Matt Wilson <msw@amazon.com>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Juergen Gross <jgross@suse.com>,
	Sergey Dyasli <sergey.dyasli@citrix.com>,
	George Dunlap <George.Dunlap@eu.citrix.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Xen-devel List <xen-devel@lists.xen.org>,
	Daniel Kiper <daniel.kiper@oracle.com>,
	David Woodhouse <dwmw@amazon.co.uk>, Roger Pau Monne <roger.>
Subject: Re: Ongoing/future speculative mitigation work
Date: Wed, 12 Dec 2018 01:32:24 -0700	[thread overview]
Message-ID: <5C10C7980200007800205563@prv1-mh.provo.novell.com> (raw)
In-Reply-To: <FB70ABC00200007CA293CED3@prv1-mh.provo.novell.com>

>>> On 11.12.18 at 19:05, <wei.liu2@citrix.com> wrote:
> On Fri, Oct 26, 2018 at 05:20:47AM -0600, Jan Beulich wrote:
>> >>> On 26.10.18 at 12:51, <george.dunlap@citrix.com> wrote:
>> > The basic solution involves having a xenheap virtual address mapping
>> > area not tied to the physical layout of the memory.  domheap and xenheap
>> > memory would have to come from the same pool, but xenheap would need to
>> > be mapped into the xenheap virtual memory region before being returned.
>> 
>> Wouldn't this most easily be done by making alloc_xenheap_pages()
>> call alloc_domheap_pages() and then vmap() the result? Of course
>> we may need to grow the vmap area in that case.
> 
> The existing vmap area is 64GB, but that should be big enough for Xen?

In the common case perhaps. But what about extreme cases, like
very many VMs on multi-Tb hosts?

> If that's not big enough, we need to move that area to a different
> location, because it can't expand to either side of the address space.

When the directmap goes away, ample address space gets freed
up.

Jan



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  parent reply	other threads:[~2018-12-12  8:32 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-18 17:46 Ongoing/future speculative mitigation work Andrew Cooper
2018-10-19  8:09 ` Dario Faggioli
2018-10-19 12:17   ` Andrew Cooper
2018-10-22  9:32     ` Mihai Donțu
2018-10-22 14:55 ` Wei Liu
2018-10-22 15:09   ` Woodhouse, David
2018-10-22 15:14     ` Andrew Cooper
2018-10-25 14:50   ` Jan Beulich
2018-10-25 14:56     ` George Dunlap
2018-10-25 15:02       ` Jan Beulich
2018-10-25 16:29         ` Andrew Cooper
2018-10-25 16:43           ` George Dunlap
2018-10-25 16:50             ` Andrew Cooper
2018-10-25 17:07               ` George Dunlap
2018-10-26  9:16           ` Jan Beulich
2018-10-26  9:28             ` Wei Liu
2018-10-26  9:56               ` Jan Beulich
2018-10-26 10:51                 ` George Dunlap
2018-10-26 11:20                   ` Jan Beulich
2018-10-26 11:24                     ` George Dunlap
2018-10-26 11:33                       ` Jan Beulich
2018-10-26 11:43                         ` George Dunlap
2018-10-26 11:45                           ` Jan Beulich
2018-12-11 18:05                     ` Wei Liu
     [not found]                       ` <FB70ABC00200007CA293CED3@prv1-mh.provo.novell.com>
2018-12-12  8:32                         ` Jan Beulich [this message]
2018-10-24 15:24 ` Tamas K Lengyel
2018-10-25 16:01   ` Dario Faggioli
2018-10-25 16:25     ` Tamas K Lengyel
2018-10-25 17:23       ` Dario Faggioli
2018-10-25 17:29         ` Tamas K Lengyel
2018-10-26  7:31           ` Dario Faggioli
2018-10-25 16:55   ` Andrew Cooper
2018-10-25 17:01     ` George Dunlap
2018-10-25 17:35       ` Tamas K Lengyel
2018-10-25 17:43         ` Andrew Cooper
2018-10-25 17:58           ` Tamas K Lengyel
2018-10-25 18:13             ` Andrew Cooper
2018-10-25 18:35               ` Tamas K Lengyel
2018-10-25 18:39                 ` Andrew Cooper
2018-10-26  7:49                 ` Dario Faggioli
2018-10-26 12:01                   ` Tamas K Lengyel
2018-10-26 14:17                     ` Dario Faggioli
2018-10-26 10:11               ` George Dunlap
2018-12-07 18:40 ` Wei Liu
2018-12-10 12:12   ` George Dunlap
2018-12-10 12:19     ` George Dunlap
2019-01-24 11:44 ` Reducing or removing direct map from xen (was Re: Ongoing/future speculative mitigation work) Wei Liu
2019-01-24 16:00   ` George Dunlap
2019-02-07 16:50   ` Wei Liu
2019-02-20 12:29   ` Wei Liu
2019-02-20 13:00     ` Roger Pau Monné
2019-02-20 13:09       ` Wei Liu
2019-02-20 17:08         ` Wei Liu
2019-02-21  9:59           ` Roger Pau Monné
2019-02-21 17:51             ` Wei Liu
2019-02-22 11:48           ` Jan Beulich
2019-02-22 11:50             ` Wei Liu
2019-02-22 12:06               ` Jan Beulich
2019-02-22 12:11                 ` Wei Liu
2019-02-22 12:47                   ` Jan Beulich
2019-02-22 13:19                     ` Wei Liu
     [not found]                       ` <158783E402000088A293CED3@prv1-mh.provo.novell.com>
2019-02-22 13:24                         ` Jan Beulich
2019-02-22 13:27                           ` Jan Beulich

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