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* [PATCH 0/4] x86: accommodate 32-bit PV guests with SMAP/SMEP handling
@ 2016-03-04 11:08 Jan Beulich
  2016-03-04 11:27 ` [PATCH 1/4] x86/alternatives: correct near branch check Jan Beulich
                   ` (4 more replies)
  0 siblings, 5 replies; 67+ messages in thread
From: Jan Beulich @ 2016-03-04 11:08 UTC (permalink / raw)
  To: xen-devel; +Cc: Andrew Cooper, Keir Fraser, Feng Wu

As was previously explained[1], SMAP (and with less relevance also
SMEP) is not compatible with 32-bit PV guests which aren't aware/
prepared to be run with that feature enabled. Andrew's original
approach either sacrificed architectural correctness for making
32-bit guests work again or by disabling SMAP also for not
insignificant portions of hypervisor code, both by allowing to control
the workaround mode via command line option.

This alternative approach disables SMAP and SMEP only while
running 32-bit PV guest code plus a few hypervisor instructions
early after entering hypervisor context or later before leaving it.

The 4th patch really is unrelated except for not applying cleanly
without the earlier ones, and the potential having been noticed
while putting together the 2nd one.

1: alternatives: correct near branch check
2: suppress SMAP and SMEP while running 32-bit PV guest code
3: use optimal NOPs to fill the SMAP/SMEP placeholders
4: use 32-bit loads for 32-bit PV guest state reload

Signed-off-by: Jan Beulich <jbeulich@suse.com>

[1] http://lists.xenproject.org/archives/html/xen-devel/2015-06/msg03888.html


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^ permalink raw reply	[flat|nested] 67+ messages in thread

end of thread, other threads:[~2016-06-21  7:17 UTC | newest]

Thread overview: 67+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-03-04 11:08 [PATCH 0/4] x86: accommodate 32-bit PV guests with SMAP/SMEP handling Jan Beulich
2016-03-04 11:27 ` [PATCH 1/4] x86/alternatives: correct near branch check Jan Beulich
2016-03-07 15:43   ` Andrew Cooper
2016-03-07 15:56     ` Jan Beulich
2016-03-07 16:11       ` Andrew Cooper
2016-03-07 16:21         ` Jan Beulich
2016-03-08 17:33           ` Andrew Cooper
2016-03-04 11:27 ` [PATCH 2/4] x86: suppress SMAP and SMEP while running 32-bit PV guest code Jan Beulich
2016-03-07 16:59   ` Andrew Cooper
2016-03-08  7:57     ` Jan Beulich
2016-03-09  8:09       ` Wu, Feng
2016-03-09 14:09         ` Jan Beulich
2016-03-09 11:19       ` Andrew Cooper
2016-03-09 14:28         ` Jan Beulich
2016-03-09  8:09   ` Wu, Feng
2016-03-09 10:45     ` Andrew Cooper
2016-03-09 12:27       ` Wu, Feng
2016-03-09 12:33         ` Andrew Cooper
2016-03-09 12:36           ` Jan Beulich
2016-03-09 12:54             ` Wu, Feng
2016-03-09 13:35             ` Wu, Feng
2016-03-09 13:42               ` Andrew Cooper
2016-03-09 14:03       ` Jan Beulich
2016-03-09 14:07     ` Jan Beulich
2016-03-04 11:28 ` [PATCH 3/4] x86: use optimal NOPs to fill the SMAP/SMEP placeholders Jan Beulich
2016-03-07 17:43   ` Andrew Cooper
2016-03-08  8:02     ` Jan Beulich
2016-03-04 11:29 ` [PATCH 4/4] x86: use 32-bit loads for 32-bit PV guest state reload Jan Beulich
2016-03-07 17:45   ` Andrew Cooper
2016-03-10  9:44 ` [PATCH v2 0/3] x86: accommodate 32-bit PV guests with SMEP/SMAP handling Jan Beulich
2016-03-10  9:53   ` [PATCH v2 1/3] x86: suppress SMEP and SMAP while running 32-bit PV guest code Jan Beulich
2016-05-13 15:48     ` Andrew Cooper
2016-03-10  9:54   ` [PATCH v2 2/3] x86: use optimal NOPs to fill the SMEP/SMAP placeholders Jan Beulich
2016-05-13 15:49     ` Andrew Cooper
2016-03-10  9:55   ` [PATCH v2 3/3] x86: use 32-bit loads for 32-bit PV guest state reload Jan Beulich
     [not found]   ` <56E9A0DB02000078000DD54C@prv-mh.provo.novell.com>
2016-03-17  7:50     ` [PATCH v3 0/4] x86: accommodate 32-bit PV guests with SMEP/SMAP handling Jan Beulich
2016-03-17  8:02       ` [PATCH v3 1/4] x86: move cached CR4 value to struct cpu_info Jan Beulich
2016-03-17 16:20         ` Andrew Cooper
2016-03-17  8:03       ` [PATCH v3 2/4] x86: suppress SMEP and SMAP while running 32-bit PV guest code Jan Beulich
2016-03-25 18:01         ` Konrad Rzeszutek Wilk
2016-03-29  6:55           ` Jan Beulich
2016-05-13 15:58         ` Andrew Cooper
2016-03-17  8:03       ` [PATCH v3 3/4] x86: use optimal NOPs to fill the SMEP/SMAP placeholders Jan Beulich
2016-05-13 15:57         ` Andrew Cooper
2016-05-13 16:06           ` Jan Beulich
2016-05-13 16:09             ` Andrew Cooper
2016-03-17  8:04       ` [PATCH v3 4/4] x86: use 32-bit loads for 32-bit PV guest state reload Jan Beulich
2016-03-25 18:02         ` Konrad Rzeszutek Wilk
2016-03-17 16:14       ` [PATCH v3 5/4] x86: reduce code size of struct cpu_info member accesses Jan Beulich
2016-03-25 18:47         ` Konrad Rzeszutek Wilk
2016-03-29  6:59           ` Jan Beulich
2016-03-30 14:28             ` Konrad Rzeszutek Wilk
2016-03-30 14:42               ` Jan Beulich
2016-05-13 16:11         ` Andrew Cooper
2016-05-03 13:58       ` Ping: [PATCH v3 2/4] x86: suppress SMEP and SMAP while running 32-bit PV guest code Jan Beulich
2016-05-03 14:10         ` Andrew Cooper
2016-05-03 14:25           ` Jan Beulich
2016-05-04 10:03             ` Andrew Cooper
2016-05-04 13:35               ` Jan Beulich
2016-05-04  3:07         ` Wu, Feng
2016-05-13 15:21         ` Wei Liu
2016-05-13 15:30           ` Jan Beulich
2016-05-13 15:33             ` Wei Liu
2016-05-13 17:02       ` [PATCH v3 0/4] x86: accommodate 32-bit PV guests with SMEP/SMAP handling Wei Liu
2016-05-13 17:21         ` Andrew Cooper
2016-06-21  6:19       ` Wu, Feng
2016-06-21  7:17         ` Jan Beulich

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