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From: Julien Grall <julien.grall@linaro.org>
To: Paul Durrant <Paul.Durrant@citrix.com>,
	'Jan Beulich' <JBeulich@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
	Wei Liu <wei.liu2@citrix.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	Andrew Cooper <Andrew.Cooper3@citrix.com>,
	"Tim (Xen.org)" <tim@xen.org>,
	George Dunlap <George.Dunlap@citrix.com>,
	Julien Grall <julien.grall@arm.com>,
	"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
	Ian Jackson <Ian.Jackson@citrix.com>,
	Daniel De Graaf <dgdegra@tycho.nsa.gov>,
	Roger Pau Monne <roger.pau@citrix.com>
Subject: Re: [PATCH v12 05/11] x86/mm: add HYPERVISOR_memory_op to acquire guest resources
Date: Fri, 20 Oct 2017 11:00:29 +0100	[thread overview]
Message-ID: <7b6b14ba-694d-3fcc-c8ab-878b6b4e26d4@linaro.org> (raw)
In-Reply-To: <89b3ddce8f934c06b9fa27ab5d766461@AMSPEX02CL03.citrite.net>

Hi Paul,

On 20/10/17 09:26, Paul Durrant wrote:
>> -----Original Message-----
>> From: Jan Beulich [mailto:JBeulich@suse.com]
>> Sent: 20 October 2017 07:25
>> To: Julien Grall <julien.grall@linaro.org>
>> Cc: Julien Grall <julien.grall@arm.com>; Andrew Cooper
>> <Andrew.Cooper3@citrix.com>; George Dunlap
>> <George.Dunlap@citrix.com>; Ian Jackson <Ian.Jackson@citrix.com>; Paul
>> Durrant <Paul.Durrant@citrix.com>; Roger Pau Monne
>> <roger.pau@citrix.com>; Wei Liu <wei.liu2@citrix.com>; Stefano Stabellini
>> <sstabellini@kernel.org>; xen-devel@lists.xenproject.org; Konrad Rzeszutek
>> Wilk <konrad.wilk@oracle.com>; Daniel De Graaf <dgdegra@tycho.nsa.gov>;
>> Tim (Xen.org) <tim@xen.org>
>> Subject: Re: [Xen-devel] [PATCH v12 05/11] x86/mm: add
>> HYPERVISOR_memory_op to acquire guest resources
>>
>>>>> On 19.10.17 at 18:21, <julien.grall@linaro.org> wrote:
>>> Looking a bit more at the resource you can acquire from this hypercall.
>>> Some of them are allocated using alloc_xenheap_page() so not assigned to
>>> a domain.
>>>
>>> So I am not sure how you can expect a function set_foreign_p2m_entry to
>>> take reference in that case.
>>
>> Hmm, with the domain parameter added, DOMID_XEN there (for
>> Xen heap pages) could identify no references to be taken, if that
>> was really the intended behavior in that case. However, even for
>> Xen heap pages life time tracking ought to be done - it is for a
>> reason that share_xen_page_with_guest() assigns the target
>> domain as the owner of such pages, as that allows get_page() to
>> succeed for them.
>>
> 
> So, nothing I'm doing here is making anything worse, right? Grant tables are assigned to the guest, and IOREQ server pages are allocated with alloc_domheap_page() so nothing is anonymous.

I don't think grant tables is assigned to the guest today. They are 
allocated using xenheap_pages() and I can't find 
share_xen_page_with_guest().

Anyway, I discussed with Stefano about it. set_foreign_p2m_entry is 
going to be left unimplemented on Arm until someone as time to implement 
correctly the function.

Cheers,

-- 
Julien Grall

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  reply	other threads:[~2017-10-20 10:00 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-17 13:24 [PATCH v12 00/11] x86: guest resource mapping Paul Durrant
2017-10-17 13:24 ` [PATCH v12 01/11] x86/hvm/ioreq: maintain an array of ioreq servers rather than a list Paul Durrant
2017-10-17 13:24 ` [PATCH v12 02/11] x86/hvm/ioreq: simplify code and use consistent naming Paul Durrant
2017-10-17 13:24 ` [PATCH v12 03/11] x86/hvm/ioreq: use gfn_t in struct hvm_ioreq_page Paul Durrant
2017-10-17 13:24 ` [PATCH v12 04/11] x86/hvm/ioreq: defer mapping gfns until they are actually requsted Paul Durrant
2017-10-17 13:24 ` [PATCH v12 05/11] x86/mm: add HYPERVISOR_memory_op to acquire guest resources Paul Durrant
2017-10-17 14:45   ` Daniel De Graaf
2017-10-19 12:22   ` Julien Grall
2017-10-19 12:57     ` Paul Durrant
2017-10-19 13:29       ` Julien Grall
2017-10-19 13:35         ` Paul Durrant
2017-10-19 14:12           ` Julien Grall
2017-10-19 14:49             ` Paul Durrant
2017-10-19 15:11               ` Jan Beulich
2017-10-19 15:37                 ` Julien Grall
2017-10-19 15:47                   ` Jan Beulich
2017-10-19 16:06                     ` Julien Grall
2017-10-19 16:21                       ` Julien Grall
2017-10-20  6:24                         ` Jan Beulich
2017-10-20  8:26                           ` Paul Durrant
2017-10-20 10:00                             ` Julien Grall [this message]
2017-10-20 10:10                               ` Paul Durrant
2017-10-23 18:04                                 ` Julien Grall
2017-10-25  8:40                                   ` Paul Durrant
2017-10-20  6:17                       ` Jan Beulich
2017-10-26 15:26   ` Jan Beulich
2017-10-26 15:32     ` Julien Grall
2017-10-26 15:39       ` Jan Beulich
2017-10-27 10:46         ` Julien Grall
2017-10-27 15:19           ` Paul Durrant
2017-10-30 12:08             ` Julien Grall
2017-10-30 13:10               ` Paul Durrant
2017-10-30 12:05     ` Paul Durrant
2017-10-17 13:24 ` [PATCH v12 06/11] x86/hvm/ioreq: add a new mappable resource type Paul Durrant
2017-10-19 12:31   ` Julien Grall
2017-10-19 12:58     ` Paul Durrant
2017-10-19 13:08       ` Julien Grall
2017-10-19 13:08         ` Paul Durrant
2017-10-26 15:36   ` Jan Beulich
2017-10-17 13:24 ` [PATCH v12 07/11] x86/mm: add an extra command to HYPERVISOR_mmu_update Paul Durrant
2017-10-17 13:24 ` [PATCH v12 08/11] tools/libxenforeignmemory: add support for resource mapping Paul Durrant
2017-10-17 13:24 ` [PATCH v12 09/11] tools/libxenforeignmemory: reduce xenforeignmemory_restrict code footprint Paul Durrant
2017-10-17 13:24 ` [PATCH v12 10/11] common: add a new mappable resource type: XENMEM_resource_grant_table Paul Durrant
2017-10-26 15:46   ` Jan Beulich
2017-10-17 13:24 ` [PATCH v12 11/11] tools/libxenctrl: use new xenforeignmemory API to seed grant table Paul Durrant

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