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From: Wei Liu <wei.liu2@citrix.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: "Juergen Gross" <jgross@suse.com>,
	"Wei Liu" <wei.liu2@citrix.com>,
	"Ian Jackson" <Ian.Jackson@eu.citrix.com>,
	"Marek Marczykowski-Górecki" <marmarek@invisiblethingslab.com>,
	Xen-devel <xen-devel@lists.xen.org>,
	"Jim Fehlig" <jfehlig@suse.com>,
	"Christian Lindig" <christian.lindig@citrix.com>,
	"David Scott" <dave@recoil.org>,
	"Boris Ostrovsky" <boris.ostrovsky@oracle.com>
Subject: Re: [PATCH RFC] tools: Drop xc_cpuid_check() and bindings
Date: Wed, 19 Jul 2017 11:32:38 +0100	[thread overview]
Message-ID: <20170719103238.dkooqcheu3covfhk@citrix.com> (raw)
In-Reply-To: <1500295083-10769-1-git-send-email-andrew.cooper3@citrix.com>

On Mon, Jul 17, 2017 at 01:38:03PM +0100, Andrew Cooper wrote:
> There are no current users which I can locate.  One piece of xend which didn't
> move forwards into xl/libxl is this:
> 
>   #   Configure host CPUID consistency checks, which must be satisfied for this
>   #   VM to be allowed to run on this host's processor type:
>   #cpuid_check=[ '1:ecx=xxxxxxxxxxxxxxxxxxxxxxxxxx1xxxxx' ]
>   # - Host must have VMX feature flag set
> 
> The implementation of xc_cpuid_check() is conceptually broken.  Dom0's view of
> CPUID is not the approprite view to check, and will be wrong in the presence
> of CPUID masking/faulting, and for HVM-based toolstack domains.
> 
> If it turns out that the functionality is required, it should be implemented
> in terms of XEN_SYSCTL_get_cpuid_policy to use the proper CPUID view.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> ---
> CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
> CC: Wei Liu <wei.liu2@citrix.com>
> CC: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
> CC: David Scott <dave@recoil.org>
> CC: Christian Lindig <christian.lindig@citrix.com>
> CC: Juergen Gross <jgross@suse.com>
> CC: Jim Fehlig <jfehlig@suse.com>
> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> 
> RFC initially for feedback, and to see if anyone does expect to be using this
> call.  It turns out that Xapi has a library function using it, but that
> function is dead so can be removed.

FAOD I am still waiting for Oracle and Suse folks to express their
opinions.

I will wait until August 4th. If I don't hear objection by then I will
just apply this patch.

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  parent reply	other threads:[~2017-07-19 10:32 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-07-17 12:38 [PATCH RFC] tools: Drop xc_cpuid_check() and bindings Andrew Cooper
2017-07-17 13:54 ` Christian Lindig
2017-07-18 20:56   ` Marek Marczykowski-Górecki
2017-07-19 10:32 ` Wei Liu [this message]
2017-07-19 10:43   ` Juergen Gross
2017-07-19 12:50     ` Boris Ostrovsky
2017-07-20 16:36       ` Wei Liu

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