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From: Wei Liu <wei.liu2@citrix.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>,
	Ian Jackson <Ian.Jackson@eu.citrix.com>,
	Jan Beulich <JBeulich@suse.com>,
	Xen-devel <xen-devel@lists.xen.org>
Subject: Re: [PATCH 4/6] tools/libxc: Remove xsave calculations from libxc
Date: Mon, 16 Jan 2017 11:44:33 +0000	[thread overview]
Message-ID: <20170116114432.GG5089@citrix.com> (raw)
In-Reply-To: <1484566830-13916-5-git-send-email-andrew.cooper3@citrix.com>

On Mon, Jan 16, 2017 at 11:40:28AM +0000, Andrew Cooper wrote:
> libxc performs a lot of calculations for the xstate leaf when generating a
> guests cpuid policy.  To correctly construct a policy for an HVM guest, this
> logic depends on native cpuid leaking through from real hardware.
> 
> In particular, the logic is potentially wrong for an HVM-based toolstack
> domain (e.g. PVH dom0), and definitely wrong if cpuid faulting is applied to a
> PV domain.
> 
> Xen now performs all the necessary calculations, using native values.  The
> only piece of information the toolstack need worry about is single xstate
> feature leaf.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> ---
> CC: Jan Beulich <JBeulich@suse.com>
> CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
> CC: Wei Liu <wei.liu2@citrix.com>

Acked-by: Wei Liu <wei.liu2@citrix.com>

> ---
>  tools/libxc/xc_cpuid_x86.c | 143 +++++----------------------------------------
>  1 file changed, 15 insertions(+), 128 deletions(-)
> 

I like this diffstat.

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  reply	other threads:[~2017-01-16 11:44 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-16 11:40 [PATCH 0/6] Further CPUID improvements Andrew Cooper
2017-01-16 11:40 ` [PATCH 1/6] x86/xstate: Fix array overrun on hardware with LWP Andrew Cooper
2017-01-16 16:26   ` Jan Beulich
2017-01-16 11:40 ` [PATCH 2/6] x86/cpuid: Introduce recalculate_xstate() Andrew Cooper
2017-01-16 16:45   ` Jan Beulich
2017-01-16 17:02     ` Andrew Cooper
2017-01-16 17:09       ` Jan Beulich
2017-01-17 11:27   ` [PATCH v2 " Andrew Cooper
2017-01-17 12:52     ` Jan Beulich
2017-01-17 15:15       ` Andrew Cooper
2017-01-17 15:28         ` Jan Beulich
2017-01-17 15:30           ` Andrew Cooper
2017-01-16 11:40 ` [PATCH 3/6] x86/cpuid: Move all xstate leaf handling into guest_cpuid() Andrew Cooper
2017-01-16 16:58   ` Jan Beulich
2017-01-16 17:07     ` Andrew Cooper
2017-01-16 11:40 ` [PATCH 4/6] tools/libxc: Remove xsave calculations from libxc Andrew Cooper
2017-01-16 11:44   ` Wei Liu [this message]
2017-01-16 11:40 ` [PATCH 5/6] x86/cpuid: Don't offer HVM hypervisor leaves to PV guests Andrew Cooper
2017-01-16 17:02   ` Jan Beulich
2017-01-17 11:01     ` Andrew Cooper
2017-01-16 11:40 ` [PATCH 6/6] x86/cpuid: Offer ITSC to domains which are automatically non-migrateable Andrew Cooper
2017-01-16 17:07   ` Jan Beulich
2017-01-16 17:26     ` Andrew Cooper
2017-01-17  9:00       ` Jan Beulich

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