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Mon, 10 Aug 2026 16:23:12 -0700 (PDT) Date: Mon, 10 Aug 2026 16:23:12 -0700 In-Reply-To: <20260728121138.1103610-5-tarunsahu@google.com> Mime-Version: 1.0 References: <20260728121138.1103610-1-tarunsahu@google.com> <20260728121138.1103610-5-tarunsahu@google.com> Message-ID: Subject: Re: [PATCH v4 04/11] KVM: Track weak reference to vm_file in struct kvm From: Sean Christopherson To: Tarun Sahu Cc: ackerleytng@google.com, fuad.tabba@linux.dev, Andrew Morton , dmatlack@google.com, Shuah Khan , Jonathan Corbet , david@redhat.com, Pasha Tatashin , Pratyush Yadav , sagis@google.com, Paolo Bonzini , Mike Rapoport , Alexander Graf , linux-kselftest@vger.kernel.org, andre.przywara@arm.com, michael.roth@amd.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, will@kernel.org, vannapurve@google.com, maz@kernel.org, fvdl@google.com, kvm@vger.kernel.org, oliver.upton@linux.dev, kvmarm@lists.linux.dev, alexandru.elisei@arm.com, skhawaja@google.com, aneesh.kumar@kernel.org, linux-doc@vger.kernel.org, David Hildenbrand , yan.y.zhao@intel.com, kexec@lists.infradead.org, suzuki.poulose@arm.com Content-Type: text/plain; charset="us-ascii" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260810_162315_184605_A134B303 X-CRM114-Status: UNSURE ( 8.67 ) X-CRM114-Notice: Please train this message. X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On Tue, Jul 28, 2026, Tarun Sahu wrote: > - Add a weak reference 'vm_file' in struct kvm under "vm_file" is effectively already claimed by vm_area_struct.vm_file. *If* we go this route, I would very strongly prefer to take a dependency on "vfio: Use file-based reference counting for KVM"[*]. I'll poke that thread, we really should land that one particular patch long before the s390-is-arm64 insanity. Empashish on "if" because this all feels backwards. It's not at all clear to me why liveupdate goes directly to guest_memfd, but then requires a token associated with the VM. https://lore.kernel.org/all/20260731130902.654679-2-seiden@linux.ibm.com