From: Borislav Petkov <bp@alien8.de>
To: Kiryl Shutsemau <kas@kernel.org>
Cc: "Pratik R. Sampat" <prsampat@amd.com>,
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, david@redhat.com, osalvador@suse.de,
thomas.lendacky@amd.com, michael.roth@amd.com
Subject: Re: [RFC PATCH 2/4] mm: Add support for unaccepted memory hotplug
Date: Thu, 27 Nov 2025 19:12:33 +0100 [thread overview]
Message-ID: <20251127181233.GBaSiUkaLzwANS_6WT@fat_crate.local> (raw)
In-Reply-To: <m3l6gcjmbabudtnqwv6w67t7iz2mpmbjyrpnmiq5k2iyargn5d@nyf2zzxx7yme>
On Thu, Nov 27, 2025 at 05:35:57PM +0000, Kiryl Shutsemau wrote:
> > ABI break for kexec? Is that a thing?
> >
> > Since when do we enforce ABI compatibility for kexec and where are we
> > documenting that?
I'll take that as a "no".
> The whole purpose of kexec() is to switch between kernel versions. This
> struct defines format we communicate information about unaccepted memory
> between kernels. The mismatch will lead to boot failure.
>
> The structure is versioned. Ideally, we should know the format of the
> structure the next kernel supports and act accordingly in the first
> kernel. Like, we can accept all memory before kexec on mismatch.
None of that matters if you kexec the same kernels.
IOW, for some reason you want to be able to kexec different kernels. The
question is why do we care?
AFAICT, nowhere do we say that there's an ABI between kexec-ed kernels...
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2025-11-27 18:13 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-25 17:57 [RFC PATCH 0/4] SEV-SNP Unaccepted Memory Hotplug Pratik R. Sampat
2025-11-25 17:57 ` [RFC PATCH 1/4] efi/libstub: Decouple memory bitmap from the unaccepted table Pratik R. Sampat
2025-11-26 11:08 ` Kiryl Shutsemau
2025-11-26 22:27 ` Pratik R. Sampat
2025-11-27 17:29 ` Kiryl Shutsemau
2025-11-25 17:57 ` [RFC PATCH 2/4] mm: Add support for unaccepted memory hotplug Pratik R. Sampat
2025-11-26 11:12 ` Kiryl Shutsemau
2025-11-26 22:27 ` Pratik R. Sampat
2025-11-27 17:40 ` Kiryl Shutsemau
2025-11-28 9:34 ` David Hildenbrand (Red Hat)
2025-12-01 17:15 ` Pratik R. Sampat
2025-12-01 18:25 ` David Hildenbrand (Red Hat)
2025-12-01 19:35 ` Pratik R. Sampat
2025-12-01 17:15 ` Pratik R. Sampat
2025-12-01 17:48 ` Kiryl Shutsemau
2025-12-01 17:58 ` Pratik R. Sampat
2025-11-26 22:31 ` Borislav Petkov
2025-11-27 17:35 ` Kiryl Shutsemau
2025-11-27 18:12 ` Borislav Petkov [this message]
2025-11-28 9:30 ` David Hildenbrand (Red Hat)
2025-11-28 11:34 ` Borislav Petkov
2025-12-01 9:18 ` David Hildenbrand (Red Hat)
2025-12-01 11:12 ` Borislav Petkov
2025-12-01 18:32 ` David Hildenbrand (Red Hat)
2025-12-01 19:10 ` Borislav Petkov
2025-12-01 20:10 ` David Hildenbrand (Red Hat)
2025-12-01 20:25 ` Borislav Petkov
2025-12-01 20:36 ` David Hildenbrand (Red Hat)
2025-12-03 14:46 ` Kiryl Shutsemau
2025-12-03 15:58 ` Borislav Petkov
2025-12-03 15:00 ` Rik van Riel
2025-11-28 9:32 ` David Hildenbrand (Red Hat)
2025-12-01 17:21 ` Pratik R. Sampat
2025-12-01 18:36 ` David Hildenbrand (Red Hat)
2025-12-01 19:35 ` Pratik R. Sampat
2025-11-25 17:57 ` [RFC PATCH 3/4] x86/sev: Introduce hotplug-aware SNP page state validation Pratik R. Sampat
2025-11-25 17:57 ` [RFC PATCH 4/4] mm: Add support for unaccepted memory hot-remove Pratik R. Sampat
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