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From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Tamas K Lengyel <tamas.lengyel@zentific.com>,
	xen-devel@lists.xenproject.org
Cc: Kevin Tian <kevin.tian@intel.com>, Wei Liu <wei.liu2@citrix.com>,
	Jun Nakajima <jun.nakajima@intel.com>,
	Razvan Cojocaru <rcojocaru@bitdefender.com>,
	Ian Jackson <ian.jackson@eu.citrix.com>,
	Jan Beulich <jbeulich@suse.com>
Subject: Re: [PATCH] vmx/monitor: CPUID events
Date: Fri, 8 Jul 2016 10:33:29 +0100	[thread overview]
Message-ID: <0cf6f009-a73b-02b1-d71d-d1277105d3d9@citrix.com> (raw)
In-Reply-To: <1467945111-11399-1-git-send-email-tamas.lengyel@zentific.com>

On 08/07/16 03:31, Tamas K Lengyel wrote:
> This patch implements sending notification to a monitor subscriber when an
> x86/vmx guest executes the CPUID instruction.
>
> Signed-off-by: Tamas K Lengyel <tamas.lengyel@zentific.com>

Is it wise having an on/off control without any further filtering?  (I
suppose that it is at least a fine first start).

cpuid is usually the serialising instruction used with rdtsc for timing
loops.  This is bad enough in VMs because of the VMExit, but becomes
even worse if there is a monitor delay as well.

~Andrew

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  parent reply	other threads:[~2016-07-08  9:33 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-08  2:31 [PATCH] vmx/monitor: CPUID events Tamas K Lengyel
2016-07-08  7:03 ` Razvan Cojocaru
2016-07-08 15:36   ` Tamas K Lengyel
2016-07-08  9:33 ` Andrew Cooper [this message]
2016-07-08 15:44   ` Tamas K Lengyel
2016-07-08 16:49     ` Andrew Cooper
2016-07-08 16:59       ` Tamas K Lengyel
2016-07-08 17:37         ` Andrew Cooper
2016-07-11  3:00 ` Tian, Kevin
2016-07-12 16:30   ` Tamas K Lengyel

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