From: Wei Liu <wei.liu2@citrix.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Ian Jackson <Ian.Jackson@eu.citrix.com>,
Wei Liu <wei.liu2@citrix.com>, Jan Beulich <jbeulich@suse.com>,
Xen-devel <xen-devel@lists.xen.org>
Subject: Re: [PATCH v5 21/21] tools/libxc: Calculate xstate cpuid leaf from guest information
Date: Thu, 7 Apr 2016 13:58:35 +0100 [thread overview]
Message-ID: <20160407125835.GS18120@citrix.com> (raw)
In-Reply-To: <1460030246-30153-22-git-send-email-andrew.cooper3@citrix.com>
On Thu, Apr 07, 2016 at 12:57:26PM +0100, Andrew Cooper wrote:
> The existing logic is broken for heterogeneous migration. By always
> advertising the host maximum xstate, a migration to a less capable host always
> fails as Xen cannot accomodate the xcr0_accum in the migration stream.
>
> By calculating xstate from the feature information (which a multi-host
> toolstack will have levelled appropriately), the guest will have the current
> hosts maximum xstate advertised, allowing for correct migration to less
> capable hosts.
>
> In addition, some further improvements and corrections:
> - don't discard the known flags in sub-leaves 2..63 ECX
> - zap sub-leaves beyond 62
> - zap all bits in leaf 1, EBX/ECX. No XSS features are currently supported.
>
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
Since this is mostly x86 code and signed off by two x86 maintainers, I'm
just rubber-stamping this patch:
Acked-by: Wei Liu <wei.liu2@citrix.com>
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next prev parent reply other threads:[~2016-04-07 12:58 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-07 11:57 [PATCH v5 00/21] x86: Improvements to cpuid handling for guests Andrew Cooper
2016-04-07 11:57 ` [PATCH v5 01/21] xen/x86: Annotate VM applicability in featureset Andrew Cooper
2016-04-07 23:01 ` Jan Beulich
2016-04-07 11:57 ` [PATCH v5 02/21] xen/x86: Calculate maximum host and guest featuresets Andrew Cooper
2016-04-07 23:04 ` Jan Beulich
2016-04-07 11:57 ` [PATCH v5 03/21] xen/x86: Generate deep dependencies of features Andrew Cooper
2016-04-07 23:18 ` Jan Beulich
2016-04-07 23:36 ` Andrew Cooper
2016-04-08 15:17 ` Jan Beulich
2016-04-08 15:18 ` Andrew Cooper
2016-04-07 11:57 ` [PATCH v5 04/21] xen/x86: Clear dependent features when clearing a cpu cap Andrew Cooper
2016-04-08 15:36 ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 05/21] xen/x86: Improve disabling of features which have dependencies Andrew Cooper
2016-04-08 15:04 ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 06/21] xen/x86: Improvements to in-hypervisor cpuid sanity checks Andrew Cooper
2016-04-08 16:10 ` Konrad Rzeszutek Wilk
2016-04-08 18:06 ` Jan Beulich
2016-04-07 11:57 ` [PATCH v5 07/21] x86/cpu: Move set_cpumask() calls into c_early_init() Andrew Cooper
2016-04-08 18:09 ` Jan Beulich
2016-04-07 11:57 ` [PATCH v5 08/21] x86/cpu: Sysctl and common infrastructure for levelling context switching Andrew Cooper
2016-04-07 16:54 ` Daniel De Graaf
2016-04-08 16:12 ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 09/21] x86/cpu: Rework AMD masking MSR setup Andrew Cooper
2016-04-08 16:13 ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 10/21] x86/cpu: Rework Intel masking/faulting setup Andrew Cooper
2016-04-08 16:14 ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 11/21] x86/cpu: Context switch cpuid masks and faulting state in context_switch() Andrew Cooper
2016-04-08 16:15 ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 12/21] x86/pv: Provide custom cpumasks for PV domains Andrew Cooper
2016-04-08 16:17 ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 13/21] x86/domctl: Update PV domain cpumasks when setting cpuid policy Andrew Cooper
2016-04-08 16:26 ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 14/21] xen+tools: Export maximum host and guest cpu featuresets via SYSCTL Andrew Cooper
2016-04-07 16:54 ` Daniel De Graaf
2016-04-08 16:32 ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 15/21] tools/libxc: Modify bitmap operations to take void pointers Andrew Cooper
2016-04-07 13:00 ` Wei Liu
2016-04-08 16:34 ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 16/21] tools/libxc: Use public/featureset.h for cpuid policy generation Andrew Cooper
2016-04-08 16:37 ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 17/21] tools/libxc: Expose the automatically generated cpu featuremask information Andrew Cooper
2016-04-08 16:38 ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 18/21] tools: Utility for dealing with featuresets Andrew Cooper
2016-04-07 11:57 ` [PATCH v5 19/21] tools/libxc: Wire a featureset through to cpuid policy logic Andrew Cooper
2016-04-07 11:57 ` [PATCH v5 20/21] tools/libxc: Use featuresets rather than guesswork Andrew Cooper
2016-04-07 11:57 ` [PATCH v5 21/21] tools/libxc: Calculate xstate cpuid leaf from guest information Andrew Cooper
2016-04-07 12:58 ` Wei Liu [this message]
2016-04-08 21:00 ` Jan Beulich
2016-04-08 21:45 ` Andrew Cooper
2016-04-08 22:38 ` Jan Beulich
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