From mboxrd@z Thu Jan  1 00:00:00 1970
From: Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>
Subject: Re: [PATCH v1 0/2] KVM: VMX: require EPTP WB (write-back) support
Date: Thu, 10 Aug 2017 16:23:09 +0200
Message-ID: <20170810142309.GA22461@flask>
References: <20170810133512.13442-1-david@redhat.com>
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Cc: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
        Bandan Das <bsd@redhat.com>
To: David Hildenbrand <david@redhat.com>
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2017-08-10 15:35+0200, David Hildenbrand:
> I also have a patch that allows VMX and nVMX to use the UC (unchached)
> memory type.
> .
> However I am not sure if we have to take care of anything special in that
> case? Any insights?

We're modifying the EPT structure through cache in root mode and I think
the cache would have to be manually flushed before entering non-root
mode.

And UC accesses are going to be slower, so I don't see the benefits for
VMX.  We can allow UC in nVMX as it will make no difference.