linux-kernel - [PATCH v2 11/13] kho: Allow kexec load before KHO finalization

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Message-ID: <20251114190002.3311679-12-pasha.tatashin@soleen.com>
Date: Fri, 14 Nov 2025 14:00:00 -0500
From: Pasha Tatashin <pasha.tatashin@...een.com>
To: akpm@...ux-foundation.org,
	bhe@...hat.com,
	pasha.tatashin@...een.com,
	rppt@...nel.org,
	jasonmiu@...gle.com,
	arnd@...db.de,
	coxu@...hat.com,
	dave@...ilevsky.ca,
	ebiggers@...gle.com,
	graf@...zon.com,
	kees@...nel.org,
	linux-kernel@...r.kernel.org,
	kexec@...ts.infradead.org,
	linux-mm@...ck.org
Subject: [PATCH v2 11/13] kho: Allow kexec load before KHO finalization

Currently, kho_fill_kimage() checks kho_out.finalized and returns
early if KHO is not yet finalized. This enforces a strict ordering where
userspace must finalize KHO *before* loading the kexec image.

This is restrictive, as standard workflows often involve loading the
target kernel early in the lifecycle and finalizing the state (FDT)
only immediately before the reboot.

Since the KHO FDT resides at a physical address allocated during boot
(kho_init), its location is stable. We can attach this stable address
to the kimage regardless of whether the content has been finalized yet.

Relax the check to only require kho_enable, allowing kexec_file_load
to proceed at any time.

Signed-off-by: Pasha Tatashin <pasha.tatashin@...een.com>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@...nel.org>
Reviewed-by: Pratyush Yadav <pratyush@...nel.org>
---
 kernel/liveupdate/kexec_handover.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c
index 461d96084c12..4596e67de832 100644
--- a/kernel/liveupdate/kexec_handover.c
+++ b/kernel/liveupdate/kexec_handover.c
@@ -1550,7 +1550,7 @@ int kho_fill_kimage(struct kimage *image)
 	int err = 0;
 	struct kexec_buf scratch;

-	if (!kho_out.finalized)
+	if (!kho_enable)
 		return 0;

 	image->kho.fdt = virt_to_phys(kho_out.fdt);
-- 
2.52.0.rc1.455.g30608eb744-goog