From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DD5FFFF885A for ; Fri, 1 May 2026 09:49:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=D3bCYUylpNTAuWyS15iXLK7eGG+AcPbkT8lStAYKXTI=; b=1z9kIEJrvbyZVs/qneAf0e/8+p Jeb+3VuVntKI4nIZPhLc5SDef/dW0a/AEkapUkwiqluwm6aWXsi5U2SP67cvmnRPup92K93jAfMqm icDfKJgUBJf+mmtURxvYow0Y66CCzSw4H83xfVEnNLvB3L7UZmXfaSe3+XsyegIb1+34Dm6WgiRlR mk/axGi+nj+wC3EH6VxMY0X9MOzRn7pACjtEo9G9kTDJQYuP7hAR90+yQyNXHAJtjrzTihr+Fyjbf gFbh5RLrrSIyLIEDU9QNxcE1FxikaCnAxsrJQ5Y66HlRn6bMQncRIzwulwU9HU3MzRVlBUP62y90v 1w5uNi+A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wIkV3-00000006YfZ-1kIt; Fri, 01 May 2026 09:49:33 +0000 Received: from mail-pf1-x429.google.com ([2607:f8b0:4864:20::429]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1wIkV1-00000006Yet-12wc for kexec@lists.infradead.org; Fri, 01 May 2026 09:49:32 +0000 Received: by mail-pf1-x429.google.com with SMTP id d2e1a72fcca58-82f33d28c1dso1033248b3a.3 for ; Fri, 01 May 2026 02:49:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1777628970; x=1778233770; darn=lists.infradead.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=D3bCYUylpNTAuWyS15iXLK7eGG+AcPbkT8lStAYKXTI=; b=Ua6ovoFQBUt332yaBQBX5jQXICCL0SBk56aDk/nQ5B/seJSBccxK55/DXZrDWp+8pX YaXDNnsWW2pCwsOkEfHxwARnKOPRZkjDWWzFt0tsc9zQzQcGivlLe33WaIFUnBxnDfEi +7xF3JarjmFw4UiL6YbH4lWMTwiFm32ZQkFk3Y/uET9+sxNeYwMzHwT4SNQ9E+9tOXRD 0oX3thyEOlqEC1Z9TtL6IkeYxWZ9DWuKwp+EHIGy5FYw9t2+p4G8RhvixVGSW37D2ZA9 qezJdaLTo3gQrxrHCRSXhCHnOpD40HfEGQgDnLdtQTucUwBXl+l0gr9t8/TatzLowdTw Zcjw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777628970; x=1778233770; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=D3bCYUylpNTAuWyS15iXLK7eGG+AcPbkT8lStAYKXTI=; b=CuByh7euR6QKftPUxjd63eqIMUz+yhrtRdP4ggPpH3daPjgXJ7PB3KO+hgo1cz7EI2 XQtLwjD01r6cliopogTPC8jQVTBOAqlH9t9f+7tQofSmPK/1DsnCa4AVKoU8OjCq2bF3 FWWJ77EE/Q2HzOgP2xkcILyAGPczUTCks58ZuqfAU118Pdz8y0+srXXI8igAjMuwvoUD Ui5tSMoHwfpue7URomyNIocPibwdI/cASzeTb35JihcQIL7m3Goqyxv1O3fJUYIiRB7y 6G+d4Mr8fzKczC38EmUuxyE25Bz2XUH2Mv6GURKgKns9b7qOfAGFxI7sVkowEYfhNeYY 4GRw== X-Forwarded-Encrypted: i=1; AFNElJ/MfMJ7j/fb8XzKLKKSTL8+l1OP2hCe9dEIlf/VKfBnfvH7A/+nA/x3YcBp67B2/No5fV/b5A==@lists.infradead.org X-Gm-Message-State: AOJu0Yy+iNgszo6UIYgVR+clzXdJiduRHT3xSBpVxyo+QVlalt1pzuFa UKZ9iwbjtD9YaP9YuyETx38KcZxbgqod7P3Om/vevnoHqCZG2lX2Libf X-Gm-Gg: AeBDietgzDsxD7w8+9gaGr1YxEQumZUqL/J4A/pGi4PYCvvHCYtlgfy6WPq8xrFpgFM Tsq0UrGXGdXHM7MVB9lh9ngoA5jWHMEEm1v7BWpuaJDPL+e62yuheGY8zOwDzvqGSyR94bSsiU1 U3+7t6H/IAN5cJKK3VVrElK41HR3qFo1PyxTUVHQz1+ZOR4/BEe0HiUn+pWqbM0EwiICc0rAZQs 2dLTcaOkMjj3HzSwNxIncfV2hOd4V9IAthoWHwC/e3T8/UU9n3YfdbxebSaOMuAvHU5sRJh9WgA 4xgS5IZbP/Er4fKCoU7njGUwqv9Cov3w697tXx5a8HtwJb1n8hAtcrgfPDgjjfED2eM33DDlD82 H2tBRw1W53av91xJ/OzWyV2RWJpkSnpWBPJrDX4DBXEy/ekmESpKjy+WmC11Z0oVrCylt05onId t0+4ipTy562rXueITL8pzspfnplsWY2mOG++v8Xg== X-Received: by 2002:aa7:8886:0:b0:82f:9985:d4a1 with SMTP id d2e1a72fcca58-8351a58db50mr2518784b3a.24.1777628970155; Fri, 01 May 2026 02:49:30 -0700 (PDT) Received: from laptop ([2001:4455:8025:be00:eebe:247e:613c:24d7]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-8351582dd55sm2042729b3a.1.2026.05.01.02.49.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 01 May 2026 02:49:29 -0700 (PDT) From: Cris Jacob Maamor To: Mike Rapoport , Pasha Tatashin , Pratyush Yadav Cc: Alexander Graf , Andrew Morton , Dan Carpenter , Greg Kroah-Hartman , kexec@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH RFC 1/5] kexec: handover: add helper to check preserved page ranges Date: Fri, 1 May 2026 17:46:33 +0800 Message-ID: <20260501094637.38650-2-crisjacobmaamor@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260501094637.38650-1-crisjacobmaamor@gmail.com> References: <20260501094637.38650-1-crisjacobmaamor@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260501_024931_291218_4B156641 X-CRM114-Status: GOOD ( 12.94 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org Signed-off-by: Cris Jacob Maamor --- include/linux/kexec_handover.h | 6 +++++ kernel/liveupdate/kexec_handover.c | 35 ++++++++++++++++++++++++++++++ 2 files changed, 41 insertions(+) diff --git a/include/linux/kexec_handover.h b/include/linux/kexec_handover.h index 8968c56d2d73..fb09943ab232 100644 --- a/include/linux/kexec_handover.h +++ b/include/linux/kexec_handover.h @@ -19,6 +19,7 @@ struct page; #ifdef CONFIG_KEXEC_HANDOVER bool kho_is_enabled(void); bool is_kho_boot(void); +bool kho_is_preserved(phys_addr_t phys, unsigned long nr_pages); int kho_preserve_folio(struct folio *folio); void kho_unpreserve_folio(struct folio *folio); @@ -51,6 +52,11 @@ static inline bool is_kho_boot(void) return false; } +static inline bool kho_is_preserved(phys_addr_t phys, unsigned long nr_pages) +{ + return false; +} + static inline int kho_preserve_folio(struct folio *folio) { return -EOPNOTSUPP; diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c index 94762de1fe5f..fe9f11190705 100644 --- a/kernel/liveupdate/kexec_handover.c +++ b/kernel/liveupdate/kexec_handover.c @@ -10,6 +10,7 @@ #define pr_fmt(fmt) "KHO: " fmt +#include #include #include #include @@ -429,6 +430,40 @@ static struct page *kho_restore_page(phys_addr_t phys, bool is_folio) return page; } +/** + * kho_is_preserved - Verify that a physical page range belongs to KHO. + * @phys: physical address of the first page in the range. + * @nr_pages: number of pages that the caller expects to access. + * + * Use this before phys_to_virt() when a physical address comes from restored + * metadata. It checks that @phys starts a KHO-preserved allocation large + * enough to cover @nr_pages. + * + * This only checks the KHO marker. It does not restore, free, or take + * ownership of the pages. + * + * Return: true if @phys starts a preserved KHO allocation large enough to cover + * @nr_pages, false otherwise. + */ +bool kho_is_preserved(phys_addr_t phys, unsigned long nr_pages) +{ + struct page *page; + union kho_page_info info; + + if (!nr_pages || !IS_ALIGNED(phys, PAGE_SIZE)) + return false; + + page = pfn_to_online_page(PHYS_PFN(phys)); + if (!page) + return false; + + info.page_private = page->private; + if (info.magic != KHO_PAGE_MAGIC || info.order >= BITS_PER_LONG) + return false; + + return nr_pages <= BIT(info.order); +} + /** * kho_restore_folio - recreates the folio from the preserved memory. * @phys: physical address of the folio. -- 2.53.0