From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f69.google.com (mail-pj1-f69.google.com [209.85.216.69]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 902A03B9DB3 for ; Mon, 10 Aug 2026 22:58:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.69 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786402702; cv=none; b=p3yeGOt1M9P9cQjm0iLxH7E+evqFMIs7ax+6UpUIE6ru3r6/SllVr1l3zaYrxhJqjh7ZaeUvd5GxVdJT6xnneToLwUj4S1hSuU/RxDDeHnjrt/YG/kbkS+Z8Xq5dNCcaqEi3PEBRnecxvhsD5ftInIby7hWJ9fHn7Acr0FdRDtY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786402702; c=relaxed/simple; bh=CFuIJ7Uu9OrHMxjTOKTqmRsJbmdzzsMA0Hirgq5XFeY=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=j1XvRTAT9fVWYZZMfRVNrulc2G+C2u+57RKmhoiFBrkYPcdun7tk1e5Eq6A1ORWG9Xz/TN8WiO8tirHZUpTOMJ1QcXMaQAG43fpVC0TduTDvqt+oeHCxgj2FxS+MItkXiNE1pPULFrLAUNF0Z9/FtE5vLHIHoPLzk8W+tdT2UTo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=BFzdxsgw; arc=none smtp.client-ip=209.85.216.69 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="BFzdxsgw" Received: by mail-pj1-f69.google.com with SMTP id 98e67ed59e1d1-38e11baa66eso2348193a91.2 for ; Mon, 10 Aug 2026 15:58:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1786402701; x=1787007501; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=2Mn9WKaRVsVTpGaOSKTBrlWB9M3O9fuL04U/nAsMmiI=; b=BFzdxsgwmV9AfYECEQb5U55p7KLFSBr1yWq0jKJgtc2uNPBAF/Ra9vEUmuP4bFDo5O 2fBcSBN81+M/Jhh1Mr45n7WXZ6tqpeZLkK8CvmATDeGurMRBKASPp/+4kVyma7fV9Asz ldyuq6Dsv51G6aA/smBxoIrNF5VySBDAvPHioJDokN+e8BOnLxnwzQuFdaDqV0xtKJ2S +LHrfNlfRx98FGJ55MA9YhsUHBjC0rht1TtMJkyMmhaypoVXC34bWQCwexkV/mct8Qai ENvvCPZWhvZUCsH26DRBUDjqfWrVS5mU/WxP6I229e/DXvsROJzSchKbs93cv/2Ea+MN 9ZBg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786402701; x=1787007501; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=2Mn9WKaRVsVTpGaOSKTBrlWB9M3O9fuL04U/nAsMmiI=; b=jXh1QUMs8X8TqH8Y4gC0wWwB4/bZ4r7dnDDgjJ/YYknqeBA1rREz+poU+AoQpzDr7V jllemJs/CZkVDoEs1yUyLQL2keqelSQP/68mpa99L3fXYts9WQJHnvdlsgk5e1lcrhkS Cu4eOcwOBaj8OyJBOQCnmmQBgGR6l0B1ZK62TQB8XC/ke2Qca/MMXDZMS56P0L4mKCFz rF3eXqrY02hswfN8e1orpA39MIqMaFCTrSi4n/Cnp1f5B1XGEJsOYEvDNK61SHGN9RkJ 5I6FaMVPY03VOElkqBhSnFGVtldtmNwh/7cGaa+3OO+xFFJakcwLZI5y2MqfcIBPen3X WAIQ== X-Forwarded-Encrypted: i=1; AHgh+RpkQXYTMUsDufk/tKIuFL5lfuXhNfznqNGP1VVRqPUqww5ZgE2E2/3zM4HcLXdEQhgIkKoJJWqmDnnN+FcIP7o=@vger.kernel.org X-Gm-Message-State: AOJu0YxyNYXbXGAQM+O+Kz9MyDZRZgJa3SLNq7Bydly2/8bg+TMjJ3cO Z8sM57/RvTOXonPBEj2pYo9FSFkuwrkw4KmGAdBgZ94l8YDFAsj05uQSt3gq+wIOq31mDjsrxCQ 9DE5trQ== X-Received: from pjse9.prod.google.com ([2002:a17:90a:77c9:b0:384:934b:9128]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:590e:b0:38e:6a44:671b with SMTP id 98e67ed59e1d1-3909d301d9cmr33802476a91.0.1786402700758; Mon, 10 Aug 2026 15:58:20 -0700 (PDT) Date: Mon, 10 Aug 2026 15:58:20 -0700 In-Reply-To: <20260728121138.1103610-2-tarunsahu@google.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260728121138.1103610-1-tarunsahu@google.com> <20260728121138.1103610-2-tarunsahu@google.com> Message-ID: Subject: Re: [PATCH v4 01/11] liveupdate: Add LIVEUPDATE_GUEST_MEMFD config option 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" On Tue, Jul 28, 2026, Tarun Sahu wrote: > Introduce the LIVEUPDATE_GUEST_MEMFD Kconfig option. This option > enables live update support for KVM guest_memfd files, enabling > guest_memfd-backed memory preservation across kernel upgrades. > > Currently this support only guest_memfd files that are full-shared > (INIT_SHARED and no support for private_mem). Why? Specifically, why do we need/want a separate Kconfig for guest_memfd liveupdate versus KVM liveupdate? I can _maybe_ see a KVM-wide Kconfig, but even that seems like a stretch given that (AFAIK) hypervisors are the one and only use-case for liveupdate.