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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> <47927c25-a317-488a-823f-ac0588f4eee4@kernel.org> <20251201111201.GAaS14AX18qeHN20xf@fat_crate.local> From: "David Hildenbrand (Red Hat)" Content-Language: en-US In-Reply-To: <20251201111201.GAaS14AX18qeHN20xf@fat_crate.local> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Queue-Id: 04781140015 X-Rspamd-Server: rspam11 X-Stat-Signature: sq51jj5ptd1gkij4kj14naezkj657jyc X-HE-Tag: 1764613965-513083 X-HE-Meta: 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 dbxCK4q7 Qt97v9rmLmANsynRQbgRH8T0BiMMAs0mnogJmhErNeNPy3FL7WRHipvSr0s+wIvhVKv9Qhi9U2GO/Guur9D/3ht3mf/AiHTSfjdprMHnKjTAOG/YFPslAC1Zz2EO7eQH83AOrNG8UfQZYyMu5rzNbZqCmzK6xLJTpuyTIb3zu7kXNgNQ7VtJ/AoEGG+JIFeq56WPGjAohVeLeTqu+fo2M0IrasuUDZ0e9rkDL8lDqeW2UWCeP1KzxIr07PMMvk0mqBtro 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 12/1/25 12:12, Borislav Petkov wrote: > On Mon, Dec 01, 2025 at 10:18:37AM +0100, David Hildenbrand (Red Hat) wrote: >> Makes sense to me, especially for confidential VMs where we pass such >> kernel-managed data from the old to the new kernel. > > It shouldn't matter, right? > > I think the question is whether the kernel should agree to the software > contract (/eyeroll) to keep the kernel ABI compatible wrt kexec. > > And I don't think we have agreed to that AFAIK. I think we are in agreement: from what I recall, this software contract used to be rather simple and stable. Looking into the details, I guess it's all about $ grep "define LINUX_EFI_" include/linux/efi.h #define LINUX_EFI_CRASH_GUID EFI_GUID(0xcfc8fc79, 0xbe2e, 0x4ddc, 0x97, 0xf0, 0x9f, 0x98, 0xbf, 0xe2, 0x98, 0xa0) #define LINUX_EFI_SCREEN_INFO_TABLE_GUID EFI_GUID(0xe03fc20a, 0x85dc, 0x406e, 0xb9, 0x0e, 0x4a, 0xb5, 0x02, 0x37, 0x1d, 0x95) #define LINUX_EFI_ARM_CPU_STATE_TABLE_GUID EFI_GUID(0xef79e4aa, 0x3c3d, 0x4989, 0xb9, 0x02, 0x07, 0xa9, 0x43, 0xe5, 0x50, 0xd2) #define LINUX_EFI_LOADER_ENTRY_GUID EFI_GUID(0x4a67b082, 0x0a4c, 0x41cf, 0xb6, 0xc7, 0x44, 0x0b, 0x29, 0xbb, 0x8c, 0x4f) #define LINUX_EFI_RANDOM_SEED_TABLE_GUID EFI_GUID(0x1ce1e5bc, 0x7ceb, 0x42f2, 0x81, 0xe5, 0x8a, 0xad, 0xf1, 0x80, 0xf5, 0x7b) #define LINUX_EFI_TPM_EVENT_LOG_GUID EFI_GUID(0xb7799cb0, 0xeca2, 0x4943, 0x96, 0x67, 0x1f, 0xae, 0x07, 0xb7, 0x47, 0xfa) #define LINUX_EFI_MEMRESERVE_TABLE_GUID EFI_GUID(0x888eb0c6, 0x8ede, 0x4ff5, 0xa8, 0xf0, 0x9a, 0xee, 0x5c, 0xb9, 0x77, 0xc2) #define LINUX_EFI_INITRD_MEDIA_GUID EFI_GUID(0x5568e427, 0x68fc, 0x4f3d, 0xac, 0x74, 0xca, 0x55, 0x52, 0x31, 0xcc, 0x68) #define LINUX_EFI_MOK_VARIABLE_TABLE_GUID EFI_GUID(0xc451ed2b, 0x9694, 0x45d3, 0xba, 0xba, 0xed, 0x9f, 0x89, 0x88, 0xa3, 0x89) #define LINUX_EFI_COCO_SECRET_AREA_GUID EFI_GUID(0xadf956ad, 0xe98c, 0x484c, 0xae, 0x11, 0xb5, 0x1c, 0x7d, 0x33, 0x64, 0x47) #define LINUX_EFI_BOOT_MEMMAP_GUID EFI_GUID(0x800f683f, 0xd08b, 0x423a, 0xa2, 0x93, 0x96, 0x5c, 0x3c, 0x6f, 0xe2, 0xb4) #define LINUX_EFI_UNACCEPTED_MEM_TABLE_GUID EFI_GUID(0xd5d1de3c, 0x105c, 0x44f9, 0x9e, 0xa9, 0xbc, 0xef, 0x98, 0x12, 0x00, 0x31) #define LINUX_EFI_LOADED_IMAGE_FIXED_GUID EFI_GUID(0xf5a37b6d, 0x3344, 0x42a5, 0xb6, 0xbb, 0x97, 0x86, 0x48, 0xc1, 0x89, 0x0a) Likely the format of these section stayed unchanged over the years. -- Cheers David