From nobody Tue Feb 10 10:18:42 2026 Received: from mail-yx1-f52.google.com (mail-yx1-f52.google.com [74.125.224.52]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3A6F92E54A7 for ; Fri, 14 Nov 2025 19:00:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.224.52 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763146824; cv=none; b=T81d1omSVUbqAHjup5QL8wPL9GQIo4RCCOoqJyzX2TbTNOwZ+jiPdD8aJWhdV2o527AufdlZPxVZhI0TLoCgG6HBzrZNQxIUh18/L0g/Dc0rDyfrANHhM+MziocxijJXvbxt3M7xKnuiVFmSDAqd30EylIKyRQq47kpvuFTMNfE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763146824; c=relaxed/simple; bh=QbiPl9slsE7jLJ0ocsqH/+MGnKsobGTfsHQSThyWxlU=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gySXbHaK9mFUf8vlT2A/g4W3pPXCks6lBAnw1EEq0caDPvyCyn/JI75y8fDtM6YjtiyJ3O4Q8+IbtbtlQtF0aRVIiV14oij0v/uekRxSuK9mpRg300eC1H2mYp3T5JGb/xMD7DkFcATMvmgN8YHwgBLoXZH+TQcnbEj2HdVvReM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=soleen.com; spf=pass smtp.mailfrom=soleen.com; dkim=pass (2048-bit key) header.d=soleen.com header.i=@soleen.com header.b=UEaE10/P; arc=none smtp.client-ip=74.125.224.52 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=soleen.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=soleen.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=soleen.com header.i=@soleen.com header.b="UEaE10/P" Received: by mail-yx1-f52.google.com with SMTP id 956f58d0204a3-640d43060d2so2086399d50.2 for ; Fri, 14 Nov 2025 11:00:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=soleen.com; s=google; t=1763146821; x=1763751621; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:to:from:from:to:cc:subject:date:message-id :reply-to; bh=01MmDex2Pd6rSH6pN9DP4qcg9OhX2+hS8KGFIWtKr/Y=; b=UEaE10/Ph5t3HLMTwlGcBlOZE+bHFE3DZT/D3oG0w4ORodYSVKqjYnigIqSb/xavfq +yRMoTNVhZbzDDVbjXrwyNnq9SSRMO4QI5xYWx4EG5xYnFMb4bwbxBPYf/ONxkAgLRp9 vfpjPL/Lwl+/hcqmXp9Pi/YK+mXCDPzfDU8NWdFinupOX6lrGn3MU0o0ZsVPWImKxKo8 kuduKT20WPbX8IhYqHwIWPYE/iHEMT4A34nrFDMz7RJV040guBRmedphl3KpKXKIMw5a hrhjoTAWWGz+Vdry7I0xzPrSAf1C8QjTRsfgNp+PU4NixL62lIG0eWrHUeco3hELRWXl qQYg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1763146821; x=1763751621; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:to:from:x-gm-gg:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=01MmDex2Pd6rSH6pN9DP4qcg9OhX2+hS8KGFIWtKr/Y=; b=q+bpEA+6Nmk2gplZHu8040v0FZ2AvGBF2NJlInKFEzlKxvxiKNVhfmFouQNkJIXZTX MTI6jbH2m+rK3uU77sNqGn0DVDOQobK6RehFbBADd47kb8fLwgXKGSl3+A0fWjpsNO7a jMReHa/aRDb09BCl8jStmhATBEVG1dNqV19PWBgOUqN980cwEZ6BSjCkbuW8pm2EsGRo Z1ZrWQ0wH1cHDcU7w8LGeE62EFDoX7stgxS7lnBdTW3Yiof3PhBJqLDBkvWRW5uBUEAC hIPaWH9gVctvPkk556P2PHPJT7r9Qf4Hu1zZ3w3HEDU03OBLIGXWh67QW+R8aGOgAhOg C7Tg== X-Forwarded-Encrypted: i=1; AJvYcCVXtt0olNutE1DwITtq5IMTEC4kn27zYR9LUUycc6lSGoUybGQuDR/TIYboS223It61KHfxaos5jo3VWgQ=@vger.kernel.org X-Gm-Message-State: AOJu0YxxGKYJoqF01uvL08v7Re7B4d+Gzw0InP/ep0mllLFiNfPvjZhF pu4GZJwoGVU0CM9oTvPjAERBuuEMqsmICMX8BkKWej0ui1NKcv//HwcMq2HxJEkjg+U= X-Gm-Gg: ASbGncuV7Z4uolLDBGCdIXbJEJ5sXOvOaFFXqYfNR4Qwau8j7v79PX9c5G13n8TIN5i hhIkqMM83xxafRaA02YwJAhV3lWn3sic+spXorp2cbbE3xC3MfHN6LuIfg+Rkj6JQY+VAz9xvsb AB4Zte2opNfRVxXPt6S5zz+xFH5NpVls7DTkUkN4iyOCz9/nyHaVTe6vSlKs3tjzhuo0VEhkHEF cdOr2FF4qYDzcdOWVdzOQAkRYkcwEukPu9YDE1vXS8ZyL6rTINYhGPY9XWNALFph/V8zxqJ2o1k LtNZ4jx+Lz8HtWQuSHxQHd/9x40CzcIelWCcfnnOhsiUInx4+jDfKEzla2JoPuMJCq32ORsZQRF OyGv/8gVMIR7a6V15e9NFdILTC9PradHQTUQEzTXFQ2uZ1V948/stXQf48wD3cGJuy/dJUs00nc rpkwI94ixQMexKymbBAsEdmH0rB0yOgg6HkMBCmxuFR/qrgnnHH8yLtae0Dr5/PIVwtqllgGlq+ 64BTOI= X-Google-Smtp-Source: AGHT+IEh8QcCgJsbND6ZreOs/yM1aLmQLxoU8QELH1/e0TqxBuMxcDBXrCAfWHESdHhM0I5QjIMNCg== X-Received: by 2002:a05:690e:1581:10b0:63f:b366:98e3 with SMTP id 956f58d0204a3-641e75052bdmr3181860d50.23.1763146821080; Fri, 14 Nov 2025 11:00:21 -0800 (PST) Received: from soleen.c.googlers.com.com (182.221.85.34.bc.googleusercontent.com. [34.85.221.182]) by smtp.gmail.com with ESMTPSA id 956f58d0204a3-6410e8f4f2esm2014058d50.0.2025.11.14.11.00.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 14 Nov 2025 11:00:20 -0800 (PST) From: Pasha Tatashin To: akpm@linux-foundation.org, bhe@redhat.com, pasha.tatashin@soleen.com, rppt@kernel.org, jasonmiu@google.com, arnd@arndb.de, coxu@redhat.com, dave@vasilevsky.ca, ebiggers@google.com, graf@amazon.com, kees@kernel.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-mm@kvack.org Subject: [PATCH v2 13/13] kho: Add Kconfig option to enable KHO by default Date: Fri, 14 Nov 2025 14:00:02 -0500 Message-ID: <20251114190002.3311679-14-pasha.tatashin@soleen.com> X-Mailer: git-send-email 2.52.0.rc1.455.g30608eb744-goog In-Reply-To: <20251114190002.3311679-1-pasha.tatashin@soleen.com> References: <20251114190002.3311679-1-pasha.tatashin@soleen.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Currently, Kexec Handover must be explicitly enabled via the kernel command line parameter `kho=3Don`. For workloads that rely on KHO as a foundational requirement (such as the upcoming Live Update Orchestrator), requiring an explicit boot parameter adds redundant configuration steps. Introduce CONFIG_KEXEC_HANDOVER_ENABLE_DEFAULT. When selected, KHO defaults to enabled. This is equivalent to passing kho=3Don at boot. The behavior can still be disabled at runtime by passing kho=3Doff. Signed-off-by: Pasha Tatashin Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: Pratyush Yadav --- kernel/liveupdate/Kconfig | 14 ++++++++++++++ kernel/liveupdate/kexec_handover.c | 2 +- 2 files changed, 15 insertions(+), 1 deletion(-) diff --git a/kernel/liveupdate/Kconfig b/kernel/liveupdate/Kconfig index eae428309332..a973a54447de 100644 --- a/kernel/liveupdate/Kconfig +++ b/kernel/liveupdate/Kconfig @@ -37,4 +37,18 @@ config KEXEC_HANDOVER_DEBUGFS Also, enables inspecting the KHO fdt trees with the debugfs binary blobs. =20 +config KEXEC_HANDOVER_ENABLE_DEFAULT + bool "Enable kexec handover by default" + depends on KEXEC_HANDOVER + help + Enable Kexec Handover by default. This avoids the need to + explicitly pass 'kho=3Don' on the kernel command line. + + This is useful for systems where KHO is a prerequisite for other + features, such as Live Update, ensuring the mechanism is always + active. + + The default behavior can still be overridden at boot time by + passing 'kho=3Doff'. + endmenu diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_h= andover.c index a7f876ece445..224bdf5becb6 100644 --- a/kernel/liveupdate/kexec_handover.c +++ b/kernel/liveupdate/kexec_handover.c @@ -52,7 +52,7 @@ union kho_page_info { =20 static_assert(sizeof(union kho_page_info) =3D=3D sizeof(((struct page *)0)= ->private)); =20 -static bool kho_enable __ro_after_init; +static bool kho_enable __ro_after_init =3D IS_ENABLED(CONFIG_KEXEC_HANDOVE= R_ENABLE_DEFAULT); =20 bool kho_is_enabled(void) { --=20 2.52.0.rc1.455.g30608eb744-goog