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Message-ID: <4d736cc0-f249-6531-c0af-7093c2c2537f@intel.com>
Date:   Tue, 13 Dec 2022 20:04:14 +0800
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Subject: Re: [PATCH v10 3/9] KVM: Extend the memslot to support fd-based
 private memory
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To:     Chao Peng <chao.p.peng@linux.intel.com>
Cc:     kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
        linux-arch@vger.kernel.org, linux-api@vger.kernel.org,
        linux-doc@vger.kernel.org, qemu-devel@nongnu.org,
        Paolo Bonzini <pbonzini@redhat.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Sean Christopherson <seanjc@google.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Arnd Bergmann <arnd@arndb.de>,
        Naoya Horiguchi <naoya.horiguchi@nec.com>,
        Miaohe Lin <linmiaohe@huawei.com>, x86@kernel.org,
        "H . Peter Anvin" <hpa@zytor.com>, Hugh Dickins <hughd@google.com>,
        Jeff Layton <jlayton@kernel.org>,
        "J . Bruce Fields" <bfields@fieldses.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Shuah Khan <shuah@kernel.org>, Mike Rapoport <rppt@kernel.org>,
        Steven Price <steven.price@arm.com>,
        "Maciej S . Szmigiero" <mail@maciej.szmigiero.name>,
        Vlastimil Babka <vbabka@suse.cz>,
        Vishal Annapurve <vannapurve@google.com>,
        Yu Zhang <yu.c.zhang@linux.intel.com>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        luto@kernel.org, jun.nakajima@intel.com, dave.hansen@intel.com,
        ak@linux.intel.com, david@redhat.com, aarcange@redhat.com,
        ddutile@redhat.com, dhildenb@redhat.com,
        Quentin Perret <qperret@google.com>, tabba@google.com,
        Michael Roth <michael.roth@amd.com>, mhocko@suse.com,
        wei.w.wang@intel.com
References: <20221202061347.1070246-1-chao.p.peng@linux.intel.com>
 <20221202061347.1070246-4-chao.p.peng@linux.intel.com>
 <cd950a78-5c5b-16ef-d0a6-ad2878af067e@intel.com>
 <20221208113003.GE1304936@chaop.bj.intel.com>
From:   Xiaoyao Li <xiaoyao.li@intel.com>
In-Reply-To: <20221208113003.GE1304936@chaop.bj.intel.com>
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On 12/8/2022 7:30 PM, Chao Peng wrote:
> On Thu, Dec 08, 2022 at 04:37:03PM +0800, Xiaoyao Li wrote:
>> On 12/2/2022 2:13 PM, Chao Peng wrote:
>>
>> ..
>>
>>> Together with the change, a new config HAVE_KVM_RESTRICTED_MEM is added
>>> and right now it is selected on X86_64 only.
>>>
>>
>>  From the patch implementation, I have no idea why HAVE_KVM_RESTRICTED_MEM is
>> needed.
> 
> The reason is we want KVM further controls the feature enabling. An
> opt-in CONFIG_RESTRICTEDMEM can cause problem if user sets that for
> unsupported architectures.

HAVE_KVM_RESTRICTED_MEM is not used in this patch. It's better to 
introduce it in the patch that actually uses it.

> Here is the original discussion:
> https://lore.kernel.org/all/YkJLFu98hZOvTSrL@google.com/
> 
> Thanks,
> Chao