From: Kiryl Shutsemau <kas@kernel.org>
To: "Pratik R. Sampat" <prsampat@amd.com>
Cc: 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, bp@alien8.de, 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 1/4] efi/libstub: Decouple memory bitmap from the unaccepted table
Date: Wed, 26 Nov 2025 11:08:05 +0000 [thread overview]
Message-ID: <phywn74ghpsqncoqsgdqjoxeqdxskibzt3yltn6bmtc25sm46g@emad5n6wp5l2> (raw)
In-Reply-To: <20251125175753.1428857-2-prsampat@amd.com>
On Tue, Nov 25, 2025 at 11:57:50AM -0600, Pratik R. Sampat wrote:
> Memory hotplug in secure environments requires the unaccepted memory
> bitmap to grow as new memory is added. Currently, the bitmap is
> implemented as a flexible array member at the end of struct
> efi_unaccepted_memory, which is reserved by memblock at boot and cannot
> be resized without reallocating the entire structure.
>
> Replace the flexible array member with a pointer.
Well, it break interoperability between kernel before and after the
patch. Consider kexec from kernel without the patch to the kernel with
the patch and then back to older kernel. It is ABI break.
Is re-allocating the entire structure such a big pain?
--
Kiryl Shutsemau / Kirill A. Shutemov
next prev parent reply other threads:[~2025-11-26 11:08 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 [this message]
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
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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