From: Tao Xu <tao3.xu@intel.com>
To: Eduardo Habkost <ehabkost@redhat.com>
Cc: "Lai, Paul C" <paul.c.lai@intel.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
"Guo, Xuelian" <xuelian.guo@intel.com>
Subject: Re: About MONITOR/MWAIT in i386 CPU model
Date: Thu, 14 Nov 2019 08:50:49 +0800 [thread overview]
Message-ID: <b1499e62-269a-2a78-d89a-3e9cdf99f919@intel.com> (raw)
In-Reply-To: <20191113224717.GN3812@habkost.net>
On 11/14/2019 6:47 AM, Eduardo Habkost wrote:
> On Wed, Nov 13, 2019 at 04:42:25PM +0800, Tao Xu wrote:
>> Hi Eduardo，
>>
>> After kvm use "-overcommit cpu-pm=on" to expose MONITOR/MWAIT
>> (commit id 6f131f13e68d648a8e4f083c667ab1acd88ce4cd), the MONITOR/MWAIT
>> feature in CPU model (phenom core2duo coreduo n270 Opteron_G3 EPYC Snowridge
>> Denverton) may be unused. For example, when we boot a guest with Denverton
>> cpu model, guest cannot detect MONITOR and boot with no warning. Should we
>> remove this feature from some CPU model?
>
> Good catch, thanks!
>
> Yes, we should remove them from Opteron_G3, EPYC, Snowridge, and
> Denverton, at least. The other older CPU models can be left
> alone: they are more useful for use with TCG than with KVM, and
> TCG supports MONITOR/MWAIT.
>
> I would like to understand why this wasn't detected during
> testing by Intel. I suggest always testing CPU models using the
> "enforce" flag to make sure warnings don't go unnoticed.
>
OK we will improve the testing.
prev parent reply other threads:[~2019-11-14 0:55 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-13 8:42 About MONITOR/MWAIT in i386 CPU model Tao Xu
2019-11-13 22:47 ` Eduardo Habkost
2019-11-14 0:50 ` Tao Xu [this message]
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