From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Xen-devel <xen-devel@lists.xen.org>
Cc: Jan Beulich <JBeulich@suse.com>
Subject: Re: [PATCH v4 11/26] xen/x86: Improvements to in-hypervisor cpuid sanity checks
Date: Thu, 24 Mar 2016 15:38:52 +0000 [thread overview]
Message-ID: <56F40A0C.70309@citrix.com> (raw)
In-Reply-To: <1458750989-28967-12-git-send-email-andrew.cooper3@citrix.com>
On 23/03/16 16:36, Andrew Cooper wrote:
> Currently, {pv,hvm}_cpuid() has a large quantity of essentially-static logic
> for modifying the features visible to a guest. A lot of this can be subsumed
> by {pv,hvm}_featuremask, which identify the features available on this
> hardware which could be given to a PV or HVM guest.
>
> This is a step in the direction of full per-domain cpuid policies, but lots
> more development is needed for that. As a result, the static checks are
> simplified, but the dynamic checks need to remain for now.
>
> As a side effect, some of the logic for special features can be improved.
> OSXSAVE and OSPKE will be automatically cleared because of being absent in the
> featuremask. This allows the fast-forward logic to be more simple.
>
> In addition, there are some corrections to the existing logic:
>
> * Hiding PSE36 out of PAE mode is architecturally wrong. It turns out that
> it was a bugfix for running HyperV under Xen, which wanted to see PSE36
> even after choosing to use PAE paging. PSE36 is not supported by shadow
> paging, so is hidden from non-HAP guests, but is still visible for HAP
> guests.
This paragraph is slightly stale.
As one further sentence, "It is also leaked into non-HAP guests when
the guest is running in PAE mode, to placate HyperV."
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next prev parent reply other threads:[~2016-03-24 15:38 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-23 16:36 [PATCH v4 00/26] x86: Improvements to cpuid handling for guests Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 01/26] xen/public: Export cpu featureset information in the public API Andrew Cooper
2016-03-24 14:08 ` Jan Beulich
2016-03-24 14:12 ` Andrew Cooper
2016-03-24 14:16 ` Jan Beulich
2016-03-23 16:36 ` [PATCH v4 02/26] xen/x86: Script to automatically process featureset information Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 03/26] xen/x86: Collect more cpuid feature leaves Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 04/26] xen/x86: Mask out unknown features from Xen's capabilities Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 05/26] xen/x86: Annotate special features Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 06/26] xen/x86: Annotate VM applicability in featureset Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 07/26] xen/x86: Calculate maximum host and guest featuresets Andrew Cooper
2016-03-29 8:57 ` Jan Beulich
2016-03-23 16:36 ` [PATCH v4 08/26] xen/x86: Generate deep dependencies of features Andrew Cooper
2016-03-24 16:16 ` Jan Beulich
2016-03-23 16:36 ` [PATCH v4 09/26] xen/x86: Clear dependent features when clearing a cpu cap Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 10/26] xen/x86: Improve disabling of features which have dependencies Andrew Cooper
2016-03-28 15:18 ` Konrad Rzeszutek Wilk
2016-03-23 16:36 ` [PATCH v4 11/26] xen/x86: Improvements to in-hypervisor cpuid sanity checks Andrew Cooper
2016-03-24 15:38 ` Andrew Cooper [this message]
2016-03-24 16:47 ` Jan Beulich
2016-03-24 17:01 ` Andrew Cooper
2016-03-24 17:11 ` Jan Beulich
2016-03-24 17:12 ` Andrew Cooper
2016-03-28 15:29 ` Konrad Rzeszutek Wilk
2016-04-05 15:25 ` Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 12/26] x86/cpu: Move set_cpumask() calls into c_early_init() Andrew Cooper
2016-03-28 15:55 ` Konrad Rzeszutek Wilk
2016-04-05 16:19 ` Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 13/26] x86/cpu: Sysctl and common infrastructure for levelling context switching Andrew Cooper
2016-03-24 16:58 ` Jan Beulich
2016-03-28 16:12 ` Konrad Rzeszutek Wilk
2016-04-05 16:33 ` Andrew Cooper
2016-03-28 17:37 ` Konrad Rzeszutek Wilk
2016-03-23 16:36 ` [PATCH v4 14/26] x86/cpu: Rework AMD masking MSR setup Andrew Cooper
2016-03-28 18:55 ` Konrad Rzeszutek Wilk
2016-04-05 16:44 ` Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 15/26] x86/cpu: Rework Intel masking/faulting setup Andrew Cooper
2016-03-28 19:14 ` Konrad Rzeszutek Wilk
2016-04-05 16:45 ` Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 16/26] x86/cpu: Context switch cpuid masks and faulting state in context_switch() Andrew Cooper
2016-03-28 19:27 ` Konrad Rzeszutek Wilk
2016-04-05 18:34 ` Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 17/26] x86/pv: Provide custom cpumasks for PV domains Andrew Cooper
2016-03-28 19:40 ` Konrad Rzeszutek Wilk
2016-04-05 16:55 ` Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 18/26] x86/domctl: Update PV domain cpumasks when setting cpuid policy Andrew Cooper
2016-03-24 17:04 ` Jan Beulich
2016-03-24 17:05 ` Andrew Cooper
2016-03-28 19:51 ` Konrad Rzeszutek Wilk
2016-03-23 16:36 ` [PATCH v4 19/26] xen+tools: Export maximum host and guest cpu featuresets via SYSCTL Andrew Cooper
2016-03-28 19:59 ` Konrad Rzeszutek Wilk
2016-03-23 16:36 ` [PATCH v4 20/26] tools/libxc: Modify bitmap operations to take void pointers Andrew Cooper
2016-03-28 20:05 ` Konrad Rzeszutek Wilk
2016-03-23 16:36 ` [PATCH v4 21/26] tools/libxc: Use public/featureset.h for cpuid policy generation Andrew Cooper
2016-03-28 20:07 ` Konrad Rzeszutek Wilk
2016-03-23 16:36 ` [PATCH v4 22/26] tools/libxc: Expose the automatically generated cpu featuremask information Andrew Cooper
2016-03-28 20:08 ` Konrad Rzeszutek Wilk
2016-03-23 16:36 ` [PATCH v4 23/26] tools: Utility for dealing with featuresets Andrew Cooper
2016-03-28 20:26 ` Konrad Rzeszutek Wilk
2016-03-23 16:36 ` [PATCH v4 24/26] tools/libxc: Wire a featureset through to cpuid policy logic Andrew Cooper
2016-03-28 20:39 ` Konrad Rzeszutek Wilk
2016-03-23 16:36 ` [PATCH v4 25/26] tools/libxc: Use featuresets rather than guesswork Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 26/26] tools/libxc: Calculate xstate cpuid leaf from guest information Andrew Cooper
2016-03-24 17:20 ` Wei Liu
2016-03-31 7:48 ` Jan Beulich
2016-04-05 17:48 ` Andrew Cooper
2016-04-07 0:16 ` Jan Beulich
2016-04-07 0:40 ` Andrew Cooper
2016-04-07 0:56 ` Jan Beulich
2016-04-07 11:34 ` Andrew Cooper
2016-03-24 10:27 ` [PATCH v4 00/26] x86: Improvements to cpuid handling for guests Jan Beulich
2016-03-24 10:28 ` Andrew Cooper
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