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From: Olaf Hering <olaf@aepfle.de>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: George Dunlap <George.Dunlap@eu.citrix.com>,
	xen-devel <xen-devel@lists.xenproject.org>,
	Paul Durrant <paul.durrant@citrix.com>,
	george.dunlap@citrix.com, Jan Beulich <JBeulich@suse.com>
Subject: Re: [PATCH 0/2] MMIO emulation fixes
Date: Wed, 29 Aug 2018 13:00:52 +0200	[thread overview]
Message-ID: <20180829110052.GC31376@aepfle.de> (raw)
In-Reply-To: <75009cae-1c9b-65d9-8269-497f94469983@citrix.com>


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On Wed, Aug 29, Andrew Cooper wrote:

> Architecturally speaking, handing #MC back is probably the closest we
> can get to sensible behaviour, but it is still a bug that Linux is
> touching the ballooned out page in the first place.

Well, the issue is that a read crosses a page boundary. If that would be
forbidden, load_unaligned_zeropad() would not exist. It can not know
what is in the following page. And such page crossing happens also in
the unballooned case. Sadly I can not trigger the reported NFS bug
myself. But it can be enforced by ballooning enough pages so that an
allocated readdir reply eventually is right in front of a ballooned
page.

Olaf

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  reply	other threads:[~2018-08-29 11:00 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-10 10:37 [PATCH 0/2] MMIO emulation fixes Paul Durrant
2018-08-10 10:37 ` [PATCH 1/2] x86/hvm/ioreq: MMIO range checking completely ignores direction flag Paul Durrant
2018-08-10 11:11   ` Andrew Cooper
2018-08-10 10:37 ` [PATCH 2/2] x86/hvm/emulate: make sure rep I/O emulation does not cross GFN boundaries Paul Durrant
2018-08-10 11:14   ` Andrew Cooper
2018-08-10 11:50     ` Paul Durrant
2018-08-10 11:50       ` Andrew Cooper
2018-08-10 11:59   ` Jan Beulich
2018-08-10 12:10     ` Paul Durrant
2018-08-10 12:01 ` [PATCH 0/2] MMIO emulation fixes Jan Beulich
2018-08-10 12:08   ` Paul Durrant
2018-08-10 12:13     ` Jan Beulich
2018-08-10 12:22       ` Paul Durrant
2018-08-10 12:37         ` Jan Beulich
2018-08-10 12:43           ` Paul Durrant
2018-08-10 12:55             ` Andrew Cooper
2018-08-10 15:08               ` Paul Durrant
2018-08-10 15:30                 ` Jan Beulich
2018-08-10 15:35                   ` Paul Durrant
     [not found]                     ` <5B6DB69D02000078001DD06A@prv1*mh.provo.novell.com>
     [not found]                       ` <eaab5a73*2910*7fb6*e1fc*08537e63088c@citrix.com>
     [not found]                         ` <92ca69e5*98b1*61e4*817a*3868f829471a@citrix.com>
2018-08-10 16:00                     ` Jan Beulich
2018-08-10 16:30                       ` George Dunlap
2018-08-10 16:37                         ` Andrew Cooper
2018-08-13  6:50                           ` Jan Beulich
2018-08-16 11:08                             ` Andrew Cooper
2018-08-29 10:36                             ` Olaf Hering
2018-08-29 10:53                               ` Andrew Cooper
2018-08-29 11:00                                 ` Olaf Hering [this message]
2018-08-29 11:09                                   ` Andrew Cooper
2018-08-29 11:14                                     ` Andrew Cooper
2018-08-29 11:26                                     ` Juergen Gross
     [not found]                                     ` <5B86773A0200004903F324A0@prv1-mh.provo.novell.com>
     [not found]                                       ` <5B867B1A0200006D03F3278E@prv1-mh.provo.novell.com>
     [not found]                                         ` <5B867D000200009103F328E2@prv1-mh.provo.novell.com>
     [not found]                                           ` <5B867F020200009E04E46402@prv1-mh.provo.novell.com>
2018-08-29 12:06                                             ` Jan Beulich
     [not found]                                       ` <5B87A68A0200001C04E5493A@prv1-mh.provo.novell.com>
2018-08-30  8:23                                         ` Jan Beulich
2018-08-30 10:42                                           ` Olaf Hering
2018-08-30  8:10                               ` Olaf Hering
2018-08-16 10:29                           ` Jan Beulich
2018-08-16 10:56                             ` Andrew Cooper
2018-08-16 11:27                               ` Jan Beulich
     [not found] <20180810103714.5112=3def=3dbf=3dbd1=3def=3dbf=3dbdpau?= =?UTF-8?Q?l.durrant@ci=3f=3d_trix.com>
     [not found] ` <fdf19f7d=ef=bf=bd1b92=ef=bf=bda9c0?= =?UTF-8?Q?=ef=bf=bd3602=ef=bf=bdb1c9807bf610@citrix.com>
     [not found]   ` <a735b4359ccc4b278?= =?UTF-8?Q?330204d9790c6ac@AMSPEX02CL03.citrite.net>
     [not found]     ` <5B6DAF9F02000078001DD0?= =?UTF-8?Q?40@prv1=ef=bf=bdmh.provo.novell.com>
     [not found]       ` <e2f77af0b2394b8f859a1f2dc1a?= =?UTF-8?Q?91797@AMSPEX02CL03.citrite.net>
     [not found]         ` <5B6DB69D02000078001DD06A@prv1?= =?UTF-8?B?77+9bWgucHJvdm8ubm92ZWxsLmNvbT4gPGVhYWI1YTcz77+9MjkxMO+/vTdmYjY=?= =?UTF-8?B?77+9ZTFmY++/vTA4NTM3ZTYzMDg4Y0BjaXRyaXguY29tPiA8OTJjYTY5ZTXvv705?= =?UTF-8?B?OGIx77+9NjFlNO+/vTgxN2Hvv70zODY4ZjgyOTQ3MWFAY2l0>
     [not found]           ` <11c0c96?= =?UTF-8?Q?5-9af7-2cec-1420-4541e281183a@citrix.com>
     [not found]             ` <5B755FBC0200007_=3d=3f?= =?UTF-8?Q?UTF-8=3fQ=3f8001DEDBF@suse.com>
     [not found]               ` <dd3c99c2-67e3-faf1-4219-85651b89?= =?UTF-8?Q?1adc@suse.com>
2018-09-04 16:24                 ` Andrew Cooper
     [not found]                   ` <651CBD680200008737554D14@prv1-mh.provo.novell.com>
     [not found]                     ` <21554C83020000C537554D14@prv1-mh.provo.novell.com>
     [not found]                       ` <06D73C83020000C037554D14@prv1-mh.provo.novell.com>
     [not found]                         ` <A283E656020000808E2C01CD@prv1-mh.provo.novell.com>
2018-09-05  7:10                           ` Jan Beulich
     [not found] <20180810103714.5112=ef=bf=bd1=ef=bf=bdpaul.durrant@ci?= =?UTF-8?Q?trix.com>
     [not found] ` <5B6D86F30?= =?UTF-8?Q?2000078001DCF85@prv1=ef=bf=bdmh.provo.novell.com>
     [not found]   ` <e8cff3ca6c154b?= =?UTF-8?Q?67a2a932af83719354@AMSPEX02CL03.citrite.net>
     [not found]     ` <fdf19f7d=ef=bf=bd1b?= =?UTF-8?B?OTLvv71hOWMw77+9MzYwMu+/vWIxYzk4MDdiZjYxMEBjaXRyaXguY29tPiA8YTcz?= =?UTF-8?Q?5b4359ccc4b278330204d9790c6ac@AMSPEX02CL03.citrite.net>
     [not found]       ` <5B6DAF9F?= =?UTF-8?Q?02000078001DD040@prv1=ef=bf=bdmh.provo.novell.com>
     [not found]         ` <e2f77af0b2394?= =?UTF-8?Q?b8f859a1f2dc1a91797@AMSPEX02CL03.citrite.net>
     [not found]           ` <5B6DB69D0200007800?= =?UTF-8?Q?1DD06A@prv1=ef=bf=bdmh.provo.novell.com>
     [not found]             ` <eaab5a73=ef=bf=bd2910?= =?UTF-8?B?77+9N2ZiNu+/vWUxZmPvv70wODUzN2U2MzA4OGNAY2l0cml4LmNvbT4gPDkyY2E2?= =?UTF-8?B?OWU177+9OThiMe+/vTYxZTTvv704MTdh77+9Mzg2OGY4Mjk0NzFhQGNpdHJpeC5j?= =?UTF-8?Q?om>
     [not found]               ` <5B75521102000078001DED13@prv1=ef=bf=bdmh.provo.novell.com>
     [not found]                 ` <?= =?UTF-8?Q?11c0c965-9af7-2cec-1420-4541e281183a@citrix.com>
     [not found]                   ` <5B755FBC0200007?= =?UTF-8?Q?8001DEDBF@suse.com>
2018-08-16 12:52                     ` Juergen Gross
2018-09-04 16:11                     ` Juergen Gross
     [not found] <20180810103714.5112=3def=3dbf=3dbd1=3def=3dbf=3dbdpau?= l.durrant@ci?= trix.com>

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