From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 571D3C5DF7D for ; Tue, 18 Aug 2026 16:11:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:Cc:To:From: Subject:Message-ID:References:Mime-Version:In-Reply-To:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=gq4c916t8aM4R9/gOTYj07vE672c6Dn+UdOcLkpJL3k=; b=J97yVNAG5lNscE7+ayOMl1h9Ph fZTX938VIe+8RP+f/BWMHUZWAKCU1c4MQztsVDiWo8O7jO/Zzxo+jq3TL3IKLunMZ6TYKcksR+URH qRee/l5kwWCvdjm0MuOjgoOe13i/2pt/RoRKT7S8LJCswSgCWyspufjPdRJiD443375CgwFePl7o9 gZk0y7WDGkKdeyNpY8IaBdeEdH+N3N4a3HwDBA5GIr6IE1182LweTF53CJSz4eeV4klVOdBM5jxk2 QEMACk6BSvBFDRk9poYRskvYwseMzDnn6ZNxUKFY0QwG7UAZ6YPV2srVH4GcdkroEddFY+x4L15Zy Dol/9HUw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wwMPH-00000008KDE-0TST; Tue, 18 Aug 2026 16:11:19 +0000 Received: from mail-ej1-x647.google.com ([2a00:1450:4864:20::647]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wwMPF-00000008KCh-0mTL for kexec@lists.infradead.org; Tue, 18 Aug 2026 16:11:18 +0000 Received: by mail-ej1-x647.google.com with SMTP id a640c23a62f3a-c15d4224f9dso284488266b.3 for ; Tue, 18 Aug 2026 09:11:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1787069475; x=1787674275; darn=lists.infradead.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=gq4c916t8aM4R9/gOTYj07vE672c6Dn+UdOcLkpJL3k=; b=I0bl4N/h5utsWK4dy07Sn5bEzgGJCdEDKxjaXWA+odFMqjjLNoSpaktrNYe4XVZDir O45+CxPhrzUrveLGFciwlPtB3erazvUhNY1H0G0rSiAzvn55hcxKdKl4Xqz9KcTeQuQi GaajbA4A8t3BWyQ07lW2rw+dMWfGUkwIYREjvvqwS3d3E9UEHpEF/6EdNJzBuMhbS0GY qFvAz3fHZNXdUQFNllrlGm+0s68V6QGSx+sAzaRo6L5K2PB2rCJ9Mcy1OWg+HKtmAlb+ DXXtaGR9g0/vJgkJGFXkybbBnFWjLzPxftylSiyABBkjEZU9HOp1v7HnCfIe+NaN2zMl /mMA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787069475; x=1787674275; 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=gq4c916t8aM4R9/gOTYj07vE672c6Dn+UdOcLkpJL3k=; b=Q9aC9PUUXTkG7rqdVj/vql+d55JlW/jHp1vF+gf0NYTEBswtKmjXDkWcF1zIox4blf nXUzmaqYsyyL64jvA/y704hZFoZbWNWMlgLeBJOm4RmT6nsE2Jfr4Beo4EJYweb3y9nt 7sYPUk0uS8XmHXr6tDXDcjyZTYsylXZt7f0k0sZiPdVOyNbasvY/3UwXZ6EDa9U/ys0O UOYeB9j+dPk4VQ6ts0bthidD2X0wvtQCEYktnSj8TdAEVP9VRducunYB+nWlUYj5Ix2S BnhWTmR6bBXSKNQ+6a82coMigTU8dfxT/ubMA0Gw0gJ3D25odsJcGVkrlpJ+hfwkmeLQ O6ew== X-Forwarded-Encrypted: i=1; AHgh+RrAjLsoFMl/BErfOv+seLhVKexGNEa8d1QL0gfCJTAHrC19dGE0zce014lqjSWSe82XFDxknw==@lists.infradead.org X-Gm-Message-State: AOJu0YyNzWHMYUJ2KEdm69BB8W0gAVSZeo/gkIeJzlugq3LUamoYSebf IMJMhjg4rKo75D00lAup81l+vteOwtmsJpAxR/OoxXghgrgbBvSoglop5iyLuaSWnkxLma5h6Gh XOc7VkFE8xJwu/y3IOA== X-Received: from edrs9.prod.google.com ([2002:aa7:c549:0:b0:6a3:6b8a:8011]) (user=tarunsahu job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6402:434c:b0:69a:928:9405 with SMTP id 4fb4d7f45d1cf-6a38a8dbbefmr17632626a12.1.1787069474414; Tue, 18 Aug 2026 09:11:14 -0700 (PDT) Date: Tue, 18 Aug 2026 16:11:13 +0000 In-Reply-To: Mime-Version: 1.0 References: <20260728121138.1103610-1-tarunsahu@google.com> <20260728121138.1103610-2-tarunsahu@google.com> <9huzqzk4zt3n.fsf@tarunix.c.googlers.com> Message-ID: <9huzlda3v272.fsf@tarunix.c.googlers.com> Subject: Re: [PATCH v4 01/11] liveupdate: Add LIVEUPDATE_GUEST_MEMFD config option From: tarunsahu@google.com To: Sean Christopherson 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="UTF-8" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260818_091117_245692_0D97197B X-CRM114-Status: GOOD ( 17.82 ) 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 Sean Christopherson writes: > On Tue, Aug 11, 2026, tarunsahu@google.com wrote: >> Sean Christopherson writes: >> >> > 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. >> >> LIVEUPDATE is used in many subsystem. It is possible to enable >> liveupdate and kvm without enabling KVM_GUEST_MEMFD. So GUEST_MEMFD >> preservation must depend on CONFIG_LIVEUPDATE and KVM_GUEST_MEMFD both. >> LIVEUPDATE_GUEST_MEMFD Kconfig is wrapper on both of them. It need not >> to be visible in menu, So I can make it hidden. WDYT? >> >> Also, KVM VM_FILE preservation and GUEST_MEMFD preservation both depends >> on LIVEUPDATE_GUEST_MEMFD in this patch series. [PATCH 05/11]* >> Which is wrong. So I will update KVM VM_FILE preservation to depend only >> on CONFIG_LIVEUPDATE. > > Or just handle it all in the makefile? E.g. > > diff --git virt/kvm/Makefile.kvm virt/kvm/Makefile.kvm > index d047d4cf58c9..e6f098498795 100644 > --- virt/kvm/Makefile.kvm > +++ virt/kvm/Makefile.kvm > @@ -13,3 +13,8 @@ kvm-$(CONFIG_HAVE_KVM_IRQ_ROUTING) += $(KVM)/irqchip.o > kvm-$(CONFIG_HAVE_KVM_DIRTY_RING) += $(KVM)/dirty_ring.o > kvm-$(CONFIG_HAVE_KVM_PFNCACHE) += $(KVM)/pfncache.o > kvm-$(CONFIG_KVM_GUEST_MEMFD) += $(KVM)/guest_memfd.o > + > +ifdef CONFIG_LIVEUPDATE > +kvm-y += $(KVM)/kvm_luo.o > +kvm-$(CONFIG_KVM_GUEST_MEMFD) += $(KVM)/guest_memfd_luo.o > +endif Sounds Good to me. Will take care of it. Thanks.