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Subject: Re: [PATCH v5 0/2] KVM: MMU: fix kvm_is_mmio_pfn()
To:     Haozhong Zhang <haozhong.zhang@intel.com>, kvm@vger.kernel.org,
        x86@kernel.org
Cc:     linux-kernel@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
        rkrcmar@redhat.com, Dan Williams <dan.j.williams@intel.com>,
        ivan.d.cuevas.escareno@intel.com, karthik.kumar@intel.com,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Olif Chapman <olif.chapman@oracle.com>,
        Mikulas Patocka <mpatocka@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Borislav Petkov <bp@suse.de>,
        Tom Lendacky <thomas.lendacky@amd.com>
References: <20171108075630.16991-1-haozhong.zhang@intel.com>
From:   Xiao Guangrong <xiaoguangrong.eric@gmail.com>
Message-ID: <f1b9f317-117b-5a40-02d1-c9367dfb4018@gmail.com>
Date:   Wed, 8 Nov 2017 17:19:26 +0800
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On 11/08/2017 03:56 PM, Haozhong Zhang wrote:
> Some reserved pages, such as those from NVDIMM DAX devices, are not
> for MMIO, and can be mapped with cached memory type for better
> performance. However, the above check misconceives those pages as
> MMIO.  Because KVM maps MMIO pages with UC memory type, the
> performance of guest accesses to those pages would be harmed.
> Therefore, we check the host memory type in addition and only treat
> UC/UC- pages as MMIO.
> 

Reviewed-by: Xiao Guangrong <xiaoguangrong@tencent.com>

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