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Sampat" , linux-mm@kvack.org, linux-coco@lists.linux.dev, linux-efi@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, dave.hansen@linux.intel.com, ardb@kernel.org, akpm@linux-foundation.org, osalvador@suse.de, thomas.lendacky@amd.com, michael.roth@amd.com References: <20251125175753.1428857-1-prsampat@amd.com> <20251125175753.1428857-3-prsampat@amd.com> <66ylzwknm4ftd6utn3nqr63jmhl2ccvcdvyi5fechfnvmfxivu@37pckhjixayh> <20251126223127.GIaSd_v7juUkaW4RTA@fat_crate.local> <20251127181233.GBaSiUkaLzwANS_6WT@fat_crate.local> <20251128113411.GAaSmIs0kSWGhCYkaA@fat_crate.local> From: "David Hildenbrand (Red Hat)" Content-Language: en-US In-Reply-To: <20251128113411.GAaSmIs0kSWGhCYkaA@fat_crate.local> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 2EC9816000E X-Stat-Signature: 95eiuh9t6j91bxfd3crofujkojk6ox89 X-Rspam-User: X-HE-Tag: 1764580725-245062 X-HE-Meta: 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 fmU15j5b Ouz1JZyzjYjwTUJr1CBgQYG7roFq9XzeDub/9yD+o0HKwfDQOybm0kyLeU6V1HTEyM+TzSTu5YNwK9qkhbg5erKMGI08i+3Nnjft3mZUg6/CkwAS7Tpdr2A0VgDIQCZPL++ephQFT0p6u3afm1BBq5+9ahJXZO90V72D/QP0AVCozp51KUOhtygCSNkWiot8HK02AZ35PJ8iKkbH98Wcuxdc9mxIkoNNfFeMDHHVnlgK1xmpb+mN5y2PuzQA1rRcBixp9 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: On 11/28/25 12:34, Borislav Petkov wrote: > On Fri, Nov 28, 2025 at 10:30:15AM +0100, David Hildenbrand (Red Hat) wrote: >> kexecing the same kernel is typically used for kdump purposes. >> >> kexecing different kernels is used for all sorts of things (live-upgrade, >> grub-emu come to mind). It's quite common to kexec different kernels, or >> maybe I misunderstood the question here? > > And my question is: since when do we enforce no-ABI-changes between kernels so > that we can kexec any kernel into any kernel? > > By that logic I should be able to kexec 5.x into 6.x. I'll bet some money that > it won't work. I *think* ordinary kexec would likely work, as I recall that it doesn't need a lot of that special kexec ABI sauce like unaccepted memory uses. Within confidential VMs (kexec ...) I am pretty sure that it's a different discussion. > > So unless it is written down somewhere, I think we should probably talk first > what we want to support and why... > > Makes sense? Makes sense to me, especially for confidential VMs where we pass such kernel-managed data from the old to the new kernel. -- Cheers David