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Message-ID: <aecdc915-8541-4933-b8cd-04ce0ade68e6@intel.com>
Date:   Tue, 31 Oct 2023 10:27:56 +0800
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Subject: Re: [PATCH v13 16/35] KVM: Add KVM_CREATE_GUEST_MEMFD ioctl() for
 guest-specific backing memory
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To:     Sean Christopherson <seanjc@google.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Marc Zyngier <maz@kernel.org>,
        Oliver Upton <oliver.upton@linux.dev>,
        Huacai Chen <chenhuacai@kernel.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Anup Patel <anup@brainfault.org>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Christian Brauner <brauner@kernel.org>,
        "Matthew Wilcox (Oracle)" <willy@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        kvmarm@lists.linux.dev, linux-mips@vger.kernel.org,
        linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org,
        linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Xu Yilun <yilun.xu@intel.com>,
        Chao Peng <chao.p.peng@linux.intel.com>,
        Fuad Tabba <tabba@google.com>,
        Jarkko Sakkinen <jarkko@kernel.org>,
        Anish Moorthy <amoorthy@google.com>,
        David Matlack <dmatlack@google.com>,
        Yu Zhang <yu.c.zhang@linux.intel.com>,
        Isaku Yamahata <isaku.yamahata@intel.com>,
        =?UTF-8?B?TWlja2HDq2wgU2FsYcO8?= =?UTF-8?Q?n?= <mic@digikod.net>,
        Vlastimil Babka <vbabka@suse.cz>,
        Vishal Annapurve <vannapurve@google.com>,
        Ackerley Tng <ackerleytng@google.com>,
        Maciej Szmigiero <mail@maciej.szmigiero.name>,
        David Hildenbrand <david@redhat.com>,
        Quentin Perret <qperret@google.com>,
        Michael Roth <michael.roth@amd.com>,
        Wang <wei.w.wang@intel.com>,
        Liam Merwick <liam.merwick@oracle.com>,
        Isaku Yamahata <isaku.yamahata@gmail.com>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
References: <20231027182217.3615211-1-seanjc@google.com>
 <20231027182217.3615211-17-seanjc@google.com>
From:   Xiaoyao Li <xiaoyao.li@intel.com>
In-Reply-To: <20231027182217.3615211-17-seanjc@google.com>
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On 10/28/2023 2:21 AM, Sean Christopherson wrote:
...
> +KVM_SET_USER_MEMORY_REGION2 is an extension to KVM_SET_USER_MEMORY_REGION that
> +allows mapping guest_memfd memory into a guest.  All fields shared with
> +KVM_SET_USER_MEMORY_REGION identically.  Userspace can set KVM_MEM_PRIVATE in
> +flags to have KVM bind the memory region to a given guest_memfd range of
> +[guest_memfd_offset, guest_memfd_offset + memory_size].  The target guest_memfd
> +must point at a file created via KVM_CREATE_GUEST_MEMFD on the current VM, and
> +the target range must not be bound to any other memory region.  All standard
> +bounds checks apply (use common sense).
> +
>   ::
>   
>     struct kvm_userspace_memory_region2 {
> @@ -6087,9 +6096,24 @@ applied.
>   	__u64 guest_phys_addr;
>   	__u64 memory_size; /* bytes */
>   	__u64 userspace_addr; /* start of the userspace allocated memory */
> +  __u64 guest_memfd_offset;

missing a tab

> +	__u32 guest_memfd;
> +	__u32 pad1;
> +	__u64 pad2[14];
>     };
>