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AJvYcCU22yUj3KHPktqbsBTF5fdP8DTGC9P++KDBuVhz5aqW/vT8cS6tqkWIUoc+8lszqMjjeRI=@vger.kernel.org X-Gm-Message-State: AOJu0YyRC8GIOojC6hnBumLqI3gAk/ro5zGeAIYw63CujG71+t1NzJBh 27rMJN+P1NHzA6mOpFrl5C60O/wUevBzOF6L4DPSdnB7lrCRL/Kh5WHVAaZcEuU9OVQpo4djxP9 HmnMAlQ== X-Google-Smtp-Source: AGHT+IE9v+AMqISEN6fUyAdtK8mFeHQvOl0cmpRw928j7ZGnBCeUKwILml7veHgu+g+g3U0uNgaRQdu3bsM= X-Received: from pjbsy11.prod.google.com ([2002:a17:90b:2d0b:b0:31a:aa02:8c50]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:1e0b:b0:30a:3e8e:ea30 with SMTP id 98e67ed59e1d1-31e662e841emr4851203a91.11.1753396418146; Thu, 24 Jul 2025 15:33:38 -0700 (PDT) Date: Thu, 24 Jul 2025 15:33:36 -0700 In-Reply-To: Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250723104714.1674617-1-tabba@google.com> <20250723104714.1674617-11-tabba@google.com> Message-ID: Subject: Re: [PATCH v16 10/22] KVM: guest_memfd: Add plumbing to host to map guest_memfd pages From: Sean Christopherson To: Xiaoyao Li Cc: Fuad Tabba , kvm@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-mm@kvack.org, kvmarm@lists.linux.dev, pbonzini@redhat.com, chenhuacai@kernel.org, mpe@ellerman.id.au, anup@brainfault.org, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, viro@zeniv.linux.org.uk, brauner@kernel.org, willy@infradead.org, akpm@linux-foundation.org, yilun.xu@intel.com, chao.p.peng@linux.intel.com, jarkko@kernel.org, amoorthy@google.com, dmatlack@google.com, isaku.yamahata@intel.com, mic@digikod.net, vbabka@suse.cz, vannapurve@google.com, ackerleytng@google.com, mail@maciej.szmigiero.name, david@redhat.com, michael.roth@amd.com, wei.w.wang@intel.com, liam.merwick@oracle.com, isaku.yamahata@gmail.com, kirill.shutemov@linux.intel.com, suzuki.poulose@arm.com, steven.price@arm.com, quic_eberman@quicinc.com, quic_mnalajal@quicinc.com, quic_tsoni@quicinc.com, quic_svaddagi@quicinc.com, quic_cvanscha@quicinc.com, quic_pderrin@quicinc.com, quic_pheragu@quicinc.com, catalin.marinas@arm.com, james.morse@arm.com, yuzenghui@huawei.com, oliver.upton@linux.dev, maz@kernel.org, will@kernel.org, qperret@google.com, keirf@google.com, roypat@amazon.co.uk, shuah@kernel.org, hch@infradead.org, jgg@nvidia.com, rientjes@google.com, jhubbard@nvidia.com, fvdl@google.com, hughd@google.com, jthoughton@google.com, peterx@redhat.com, pankaj.gupta@amd.com, ira.weiny@intel.com Content-Type: text/plain; charset="us-ascii" On Wed, Jul 23, 2025, Xiaoyao Li wrote: > On 7/23/2025 6:47 PM, Fuad Tabba wrote: > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > > index a1c49bc681c4..e5cd54ba1eaa 100644 > > --- a/arch/x86/kvm/x86.c > > +++ b/arch/x86/kvm/x86.c > > @@ -13518,6 +13518,16 @@ bool kvm_arch_no_poll(struct kvm_vcpu *vcpu) > > } > > EXPORT_SYMBOL_GPL(kvm_arch_no_poll); > > +#ifdef CONFIG_KVM_GUEST_MEMFD > > +/* > > + * KVM doesn't yet support mmap() on guest_memfd for VMs with private memory > > + * (the private vs. shared tracking needs to be moved into guest_memfd). > > + */ > > +bool kvm_arch_supports_gmem_mmap(struct kvm *kvm) > > +{ > > + return !kvm_arch_has_private_mem(kvm); > > +} > > + > > I think it's better to move the kvm_arch_supports_gmem_mmap() stuff to patch > 20. Because we don't know how kvm_arch_supports_gmem_mmap() is going to be > used unitll that patch. No strong preference on my end.