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Thu, 05 Jun 2025 01:45:17 -0700 (PDT) MIME-Version: 1.0 References: <20250527180245.1413463-1-tabba@google.com> <20250527180245.1413463-9-tabba@google.com> In-Reply-To: From: Fuad Tabba Date: Thu, 5 Jun 2025 09:44:40 +0100 X-Gm-Features: AX0GCFugMIh1YPooIeoODj-4bgJGXFKwzjZX0F6CPJdRrHBnuFlUmoXPsINMIGU Message-ID: Subject: Re: [PATCH v10 08/16] KVM: guest_memfd: Allow host to map guest_memfd pages To: Vlastimil Babka Cc: kvm@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-mm@kvack.org, pbonzini@redhat.com, chenhuacai@kernel.org, mpe@ellerman.id.au, anup@brainfault.org, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, seanjc@google.com, viro@zeniv.linux.org.uk, brauner@kernel.org, willy@infradead.org, akpm@linux-foundation.org, xiaoyao.li@intel.com, 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, 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="UTF-8" X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 7E28110000E X-Stat-Signature: aybpxjzz8w9aj7pfqocoifuqqj8beqgq X-Rspam-User: X-HE-Tag: 1749113118-353451 X-HE-Meta: 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 hZ8cToSz 2IFzFfnLutrgo112Do5ZvtHT/fSpZXyLGaNItXsJnimEv+DgfyaW+nHTrZrCPSBa4KTWSAhlxYr3j98yE0av2QRhtxMGA9W1653FJtzxfrsfK93UQrVtqL+pWlDQSMLCD5U+DC/dgVUFWFx/EImO6Wx8A3pHMjtnJI109ZOCFEfbJysFXz1puOdBj+W52wDr7/Ss9JkDG+epwWzEzkogffmtjQD/C1CiAyCkoUc5xKRz4HxSShtRYya8KADtOiY8Q54cheG8uwq93NlFfDlpj5nZiCLf9EIluY/Lbn91KaQJH/RYEoyW3wHkWACrMLaWjgZ8hBM62hl9wnfIUvTfbazg2KnPNAIj8UJKvNPSHqdof9ybyjxGaUm8S2A== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi Vlastimil On Thu, 5 Jun 2025 at 09:28, Vlastimil Babka wrote: > > On 5/27/25 20:02, Fuad Tabba wrote: > > This patch enables support for shared memory in guest_memfd, including > > mapping that memory at the host userspace. This support is gated by the > > configuration option KVM_GMEM_SHARED_MEM, and toggled by the guest_memfd > > flag GUEST_MEMFD_FLAG_SUPPORT_SHARED, which can be set when creating a > > guest_memfd instance. > > > > Co-developed-by: Ackerley Tng > > Signed-off-by: Ackerley Tng > > Signed-off-by: Fuad Tabba > > > > > diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig > > index 559c93ad90be..df225298ab10 100644 > > --- a/virt/kvm/Kconfig > > +++ b/virt/kvm/Kconfig > > @@ -128,3 +128,8 @@ config HAVE_KVM_ARCH_GMEM_PREPARE > > config HAVE_KVM_ARCH_GMEM_INVALIDATE > > bool > > depends on KVM_GMEM > > + > > +config KVM_GMEM_SHARED_MEM > > + select KVM_GMEM > > + bool > > + prompt "Enable support for non-private (shared) memory in guest_memfd" > > Due to this "prompt" line, the toggle for this appears on the front page on > make menuconfig, or is asked during make oldconfig etc. > Seems not intended, no other options in this Kconfig have prompts, and the > later patch selects this option. So the prompt should be removed, otherwise > it's a Linus yelling hazard :) Ack, and thanks for the reviews! Cheers, /fuad